Special Issue: EIROforum - February 2007 ISSN 1023-9006

Between quarks and hypernovae A matter of life…

CERN • EFDA • ILL • ESRF • EMBL • ESA • ESO 2 RTD info Special Issue: EIROforum February 2007

Terrae incognitae Editorial At the same time, the articles put the spotlight Science shrouds our knowledge like a black on matter, life and evolution. hole, at the same time paradoxically highlighting the extent of our ignorance. This is a paradox we should But the patchwork they illuminate also reveals bear in mind, especially at a time when many In this special edition of RTD info, we present the extent of the gaps in our knowledge, the terrae deplore the scientific ignorance of the general details of some of the latest research currently being incognitae. For example, many of the fundamental public. After all, wise men are, essentially, ignorant! carried out by the seven major European organisations characteristics of the universe are still unknown, As the saying goes, “The more you know, the more that make up EIROforum, demonstrating the brilliance while a mysterious dark energy, about which we you realise how little you know.” Without a doubt, and excellence of the science whose frontiers are know almost nothing, appears to permeate our society would benefit from cultivating this kind of constantly being pushed back by this Old Continent space-time continuum, exerting a profound effect ignorance even more, and encouraging worldwide of ours. on the universe. exploration of these terrae incognitae.

RTD info – Special Issue: EIROforum ILL 4 “The EIROforum has become a 10 The promise of the large collider 17 Neutrons in the service of science major player in European science” The most powerful particle accelerator ever The Laue-Langevin Institute in Grenoble (FR) Interview with Bill Stirling, Director General built, the LHC, will be inaugurated at CERN represents one of the largest sources of of ESRF and Chairman of EIROforum. in 2007. It should allow scientists to discover neutrons in the world, enabling scientists to the secrets of matter right from its origins. penetrate the structure of matter. 5 Bringing science out of the lab EFDA 18 2 A close-up of EIROforum's two-pronged initiative Is energy really equal to mc ? for teachers: the magazine, Science in School, 12 All eyes are on ITER ILL’s GAMS 4 gamma-ray spectrometer has and the festival, Science on Stage. Will humanity be able to rely on a new source provided verification of Einstein’s fundamental of energy which is unlimited, clean and theorem with a precision of 0.00004%. CERN controllable? The answer could be provided by 6 Matter: the fundamental particles the ITER reactor, which becomes operational 20 The mystery of Martian in 2016. More than 6 500 scientists from every magnetism continent, Nobel Prize winners and young 13 Researchers have been able to demonstrate researchers rub shoulders in Geneva at the A calculated gamble that the magnetic anomalies revealed by the largest particle physics centre in the world. We meet David Ward, a specialist in plasma Mars Global Surveyor probe can be explained physics involved in the preparation of ITER. by the presence of pyrrhotite. 7 And then there were particles 14 Elementary particles hark back to an era when The ambitious adventure of fusion 21 From neutrons to neurons the universe was still smaller than a pin head… The challenge of fusion? To reproduce the sun Biologists are resorting more and more to Rolf Landua explains. here on earth – a process demanding neutron beams in order to decipher living temperatures in the region of 150 million material. Example: neural cell adhesion 8 Help from the strings degrees. molecules (NCAM). Alongside the ‘standard’ model of particle 16 ESRF physics, we examine the new vision brought JET, the pioneering test bed about by mathematical string theory. for ITER 22 The era of new light Without JET, ITER would never see the light Around the synchrotron at ESRF, some forty of day. And it is at JET where the validity beamlines enable microscopic specimens, and feasibility of numerous scientific invaluable to researchers from many different and technological options considered for disciplines, to be observed. the reactor at Cadarache are being assessed.

Notice A magazine providing information on European research, 102 000 copies of this issue have been printed. Neither the European Commission, nor any person acting RTD info is published in English, French, German and Spanish All issues of RTD info can be consulted on-line at on its behalf, may be held responsible for the use to which by the Information and Communication Unit of the European the Research DG’s website: information contained in this publication may be put, or for Commission’s Research DG. http://ec.europa.eu/research/rtdinfo/index_en.html any errors which, despite careful preparation and checking, Editor in chief: Michel Claessens may appear. Tel.: +32 2 295 9971 © European Communities, 2007 Non-commercial reproduction authorised, subject to Fax: +32 2 295 8220 acknowledgement of source. E-mail: [email protected] EnCover: couverture: Cluster of Mousson galaxies aushot Niger by ESO's © Thierry VLT in LebelChile. © ESO RTD info Special Issue: EIROforum February 2007 3

23 Seeing the invisible 30 Who was Urbilateria? 38 Our neighbours – The techniques used on the beamlines make it A little marine worm, Platynereis, is a lot closer Mars and Venus possible to monitor chemical and biological to Homo Sapiens than insects… We know this If for Mars it's the question of water that Urbilateria (600 million reactions within extremely short timeframes. thanks to studies of fascinates us, for Venus it is the ‘infernal’ years old). conditions which govern its surface. 24 Life through the eye of the synchrotron 32 In the beginning, there was shape ES0 Interview with Eric Karsenti, head of the Cell Biologists are using the synchrotron more and 39 The fascination of the cosmos Biology and Biophysics unit. more in order to understand life. The seven ESO is the largest inter-governmental beamlines of the ESRF dedicated to protein ESA organisation in the field of astronomy and crystallography represent about a quarter of its astrophysics in Europe. Its telescopes are scientific activity. 33 European space without frontiers located in Chile. The European Space Agency (ESA) is 26 Deciphering the origins of life a remarkable example of international 40 The black hole saga Numerous researchers from various cooperation bringing together different EU Enigmatic black holes are revealing more and disciplines are using ‘hard’ X-rays, Member States, Switzerland and Canada. more secrets about the nature of the evolution for example in palaeontology. of galaxies. 34 The revolutions of offshore EMBL science 42 The message of the 27 At the cutting edge of European Interview with David Southwood, gamma-ray bursts life sciences Director of Science at ESA. Many gamma-ray bursts originate from Independence, interdisciplinarity, welcoming distances of over 12.5 billion light years away. young researchers, doctoral programmes and 36 The sentinels of the Earth System These represent the traces of the most violent “science-society” relationships are on the Since 2004, the goal of ESA’s Living Planet energy release in the universe after the programme of EMBL's five laboratories. programme has been to develop the global Big Bang. capability to understand the way the earth 28 The tree of life in the genomic era works, predict changes and limit any harmful 44 The search for exoplanets In 2006, six researchers led by Peer Bork effects. A new field of research is open to astronomers: published a new summary of the “tree of life” exoplanets, more than 200 of which have been in Science. The work is based on knowledge identified in recent years. of the genome, shedding new light on our origins.

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“EIROforum has become a major player in European science”

He has been the Director General of the ESRF (European Synchrotron Radiation Facility) since 2001, covering essentially the period during which the EIROforum collaboration has matured. Today, Bill Stirling talks about his experience as chairman of this group, its past and its directions for the future. Bill Stirling (left) with the European Commissioner for Science and Research, Janez Potocˇnik What is the value of EIROforum today? EIROforum is a very positive collaboration where seven institutes share their experience of science at the highest level. One of our aims is to develop the scientific capabilities of Europe in the complicated environment of national science, science funded by the European Union, intergovernmental What effect will the ERC have on the EIRO institutes? science like ours, and world science. The European Research Council, if it is properly supported, will repre- We try to create sufficiently long-term strategies to be in a position to sent a fundamental shift in science funding in Europe. The effects on answer the really important scientific questions of the future, to motivate the EIRO members will initially be indirect. We run research infrastruc- our staff, to find the necessary funding and to balance the international tures that provide scientific services in a wide range of fields to programmes of our institutes with the national needs of our Member European scientists. The ERC will be providing money to the very best Countries. For many of these issues our relationship with the European researchers to carry out their scientific research. Therefore, facilities Commission is of growing importance to us. like those in the EIROforum will benefit because these researchers will Personally, I am always struck by the fact that the questions I consider use them. In general I am very enthusiastic, because the ERC’s purpose important in the context of the use of synchrotron radiation across is to support excellence in research. This will undoubtedly “boost” Europe are very similar, in many ways, to the issues other EIROforum European science but there is still a risk that juste retour at the natio- organisations face in the development of particle physics, or space nal level might dampen the positive effects of the ERC. I hope that the science, for example. ERC will be strong enough to resist this tendency.

The big European infrastructures have been developed outside the You have chaired EIROforum for the last six months. How did this man- European Union and its research policy. However, collaboration with the date change your perspective of EIROforum? European Commission is intensifying over the years. Will this tendency I am fascinated by the range of activities in which EIROforum is involved. continue and expand? There is hardly a day without an e-mail suggesting that EIROforum At the moment, organisations such as the ESRF are set up to satisfy the participate in a science exhibition, a science conference, a recruitment scientific needs primarily, but not only, of their Member States. However, fair… the list is endless. EIROforum has matured to the extent that it I can see the stronger implication of the European Commission through is now accepted as a major player in European science. It is considered the different schemes in FP7, the Marie Curie Fellowships and so on. It is as an essential participant at major scientific events in Europe and clear that some of our science, such as particle physics, can only operate increasingly, worldwide. This is not really surprising because, after all, at a supranational level, but that is not the case for the science carried out each of the EIROforum organisations is a leader in its own scientific field. at all the EIROs. Of course, there are programmes that will benefit us. The European Strategy Forum on Research Infrastructures (ESFRI) roadmap represents (1) Under the 7th framework programme, the ERC has become a new financing a very direct way in which Europe can and will influence the future of the agency through which the European scientific community chooses to support EIROforum members, since some of us feature in this roadmap. The research into emerging fundamental domains. creation of the European Research Council (ERC) (1) is of crucial importance for the future of excellent science in Europe, including science carried out by the EIROforum partners. For more information www.eiroforum.org/ EIROforum RTD info Special Issue: EIROforum February 2007 5

Bringing science out of the lab

Science is moving more rapidly than ever: one groundbreaking discovery follows the next. While schoolteachers have trouble keeping up with the latest research, many pupils call science lessons “boring”. In Spring 2006, EIROforum responded to this contradiction by launching Science in School, the first international, multi-disciplinary journal for innovative science teaching.

“ cience is becoming increasingly international and interdiscipli- nary,” says Eleanor Hayes, editor of the quarterly journal, based at SEMBL. “Education systems may be national, but children across Science on Stage the world are curious about the same types of things. The most exciting development of the day may happen anywhere in any field: students may How do we convey to young people the wonder of research and suddenly want to talk about a discovery on Mars, a medical breakthrough discovery? How do we ensure that in the future we have enough or a natural disaster.” For this reason, Science in School addresses scientists and engineers, increasingly needed by society? What science teaching not only across Europe, but also across disciplines. resources can Europe deploy to reinforce science teaching in primary Popular among science teachers, researchers and others involved in and secondary schools? science education, Science in School covers the latest discoveries, These major questions will be discussed during the European teaching materials, interviews with teachers and scientists, reviews of festival Science on Stage (Science en Scène), which will take resources, and more. Topics in the first three issues have included the place in Grenoble from 2 to 6 April 2007. This event, organised chemistry of chocolate, the genetic aftermath of Chernobyl, Muslim by EIROforum and supported by the European Commission, is a contributions to Western science, how to build the DNA helix out of unique opportunity for 500 science teachers from some thirty empty bottles and what teenagers really think about science. European countries to meet up and exchange ideas on best “Scientists across Europe, including those in EIROforum labs, are teaching practices. continually making discoveries that they would be able and willing to By combining entertaining and enjoyable approaches with in- explain to young people, but there was no central mechanism to help depth reflection, Science on Stage may be looked upon as a kind them do this,” says Bill Stirling, Director General of the European of laboratory, where the most original ideas coexist with the most Synchrotron Radiation Facility. demanding teaching experiments. Between the ‘forum’, where Promoting communication between scientists and schools is a key goal each person can explain their plans to their colleagues from other of the journal. Recognising that the true experts are those who are doing countries; and the training workshops, where teachers find class- the work, Science in School relies on two main groups of authors: the rooms for trying out new practices; all paths are possible and an scientists doing the research and the teachers who use the materials. interdisciplinary approach reigns. Teachers also have an opportunity Experienced teachers review the articles, and provide tips on how to use to meet scientists working within the European institutes belonging the articles in the classroom. to EIROforum. The approach is working: readers in over 30 European countries have This programme stems from the first Physics on Stage organised responded so enthusiastically that EIROforum is now printing 30 000 copies at CERN in 2000. National committees have been set up in of Science in School, up from the initial 20 000. The print copies are in 29 countries. They form the basic structure of the Science on English, and are sent free of charge to science teachers across Europe. Stage programme, with the objective of making science teaching Although the English version is popular, the language of the classroom more attractive, capitalising on the natural curiosity of children is usually the local language. The Science in School team are therefore and adolescents, and showing them that research is a fascinating working with scientists and teachers across Europe to put translated activity that is constantly evolving. Their mission is also to ask, articles on the journal website. “The most frequent request from our rea- in a public forum, major questions regarding the future of education ders has been for us to keep on publishing - and in as many languages in Europe. as possible,” explains Eleanor Hayes. “Thanks to many volunteers, we On 5 April 2007, in Grenoble, science teachers will be able to already have articles online in sixteen European languages. But it’s an discuss matters directly with decision-makers, during a round ongoing task, so if you’d like to help, we’d be happy to hear from you.” table on the subject of Challenges to Europe: European science education in the future, chaired by the European Commissioner for Science and Research, Janez Potocˇnik.

For more information Contacts www.scienceonstage.net Iris Mazuré For more information Contact [email protected] www.scienceinschool.org [email protected] Media contact - Montserrat Capellas [email protected] 6 RTD info Special Issue: EIROforum February 2007 CERN

Matter: the fundamental particles The largest particle physics centre in the world is located in Europe. It straddles the Franco-Swiss border, near Geneva. At CERN – the European Organisation for Nuclear Research, which is focused on the science of nuclear matter rather than on the exploitation of atomic energy – there are over 6 500 scientists. They are mainly physicists and come from all over the world. Young scientists rub shoulders with the most experienced researchers in this multilingual laboratory. CERN provides them with powerful particle accelerators with the aim of studying the ultimate constituents of matter and the forces that hold them together. Aerial View of CERN with the path of the LEP tunnel and the future LHC. © CERN ounded in 1954, foreshadowing a European Research Area, this ambitious enterprise involves 20 Member States. It has fully Faccomplished its initial goal: to create a world-class organisation for research in fundamental physics, and to do it in the Old World. Educating the young and curious CERN’s success can be measured by the ever more efficient performance of the ‘machines’ built over half a century. From the first 600MeV-proton CERN is a lab that is open to the world in every sense. Here, research Synchro-Cyclotron (SC) in 1957 to the Large Hadron Collider (LHC) – is transparent, with researchers who are more than willing to communi- the particle accelerator that will observe matter in unprecedented detail cate their passion. Educating the “general public” on advances in by the end of 2007 – this pan-European laboratory has equipped itself contemporary physics is a permanent part of the job developed by the with tools that have helped broaden its research fields and make institute. Guided tours in several languages are organised throughout fundamental discoveries in physics. the year [email protected]. Discovery Monday, once a month, at Numerous Nobel Prize winners, such as Carlo Rubbia and Simon Van night, presents an aspect of research done in the labs. The Website der Meer, Georges Charpak, Sam Ting and Burt Richter, and Jack www.cern.ch is meant for anybody who is curious about physics and/or Steinberger, have worked at CERN. is interested in knowing more about this great European research centre. It is here that Charpak’s “multiwire proportional chambers” revolutionised A link [email protected] allows everybody to ask questions. the electronic detection of particles, and here that it was discovered that neutrinos could interact with other particles while remaining neutrinos. CERN attaches great importance to educating the younger generations The first proton-antiproton collider was used at CERN, and the historic – the scientists of the future – and their teachers. A teaching strategy discovery of W and Z bosons that confirmed the electroweak theory, (seminars, online information, school visits, virtual educational tools, unifying weak and electromagnetic forces, was made here too. Also, in multimedia resources, etc.) has been developed, aimed at promoting a totally different field, it was at CERN that Tim Berners-Lee proposed innovative teaching techniques. All of this is geared towards showing a distributed information system based on hypertext, which everybody that science is a great adventure and that physics can be learned while now knows as the World-Wide Web. “having fun”.

> www.cern.ch CERN RTD info Special Issue: EIROforum February 2007 7

And then there were particles

The appearance of particles dates back to a period physicists Rolf Landua during a videoconference on fusion, organised by EIROforum and find embarrassing, one when the amount of energy active EFDA. This student event took place at in the Universe was so enormous that they simply cannot the Deutsches Museum in Munich in describe it. It is, however, possible to imagine the birth of 2006. the elementary building blocks that make up matter and © Hermann Heyer energy. How? Let Rolf Landua, a physicist at CERN, explain.

n what framework did elementary particles come into existence? along with their antiparticles, producing spurts of energy which, in turn, The issue goes back to an era when the universe was smaller than the turn into more particles. During this cosmic game of billiards, between Ihead of a pin. Since there were as yet no subatomic particles, it was matter and antimatter, the heavier particles break down, producing lighter empty. Empty? But how can anything occur in emptiness? Simply and more stable particles. All these particles collide happily at extremely because, to physicists, emptiness is not the absence of everything, as is high speeds to produce still more particles, which can be either light or generally supposed. heavy. “Emptiness is the most complicated structure in physics,” explains Rolf Immediately after the Big Bang, at a timescale far outside our perception Landua, a physicist at CERN. Actually, perfect emptiness does not exist – a period of 10-35 seconds has elapsed – the Universe began its in nature. Just as a line is never perfectly straight (it’s just a mathematical expansion. Just as one can dilute syrup in water, because of the expansion definition with no physical reality), energy is never entirely equal to zero of the universe, matter and energy in the universe dilute themselves in at any point in space. Just as a surface covered with wheat is termed a an ever-expanding environment. The particles consequently have much wheat field, the term energy field is used. “Emptiness is full of all kinds of less opportunity to collide. But when a collision does occur, the energy fields, for example electromagnetic fields. Their total energy is never zero; is weaker, and therefore lighter particles are created. it actually fluctuates incessantly over time. It is something like hyperacti- vity syndrome.” (1) Archaeological physics From energy to mass After a millionth of a second, the matter that makes up the universe is How can particles be obtained from these fields? “Restricted relativity the very matter which we can now observe. The heavier particles have teaches us that energy is also mass. That is the significance of Einstein’s disintegrated. What was previously produced can only be studied in now famous E=mc2 equation. Energy can, then, be converted into particles accelerators which collide particles at very high energies. “Particle and particles into energy.” So, physicists feel that, during the earliest physicists are a little like archaeologists. They try to reproduce energy moments of the universe, the vacuum was filled with some form of unknown levels from just after the Big Bang so they can reproduce the massive energy. This is how, spontaneously, pairs of particles and antiparticles particles that are now extinct, just as other specialists try to reconstruct were created due to the fluctuations of energy in the emptiness. This dinosaurs.” Among these are some mysterious supersymmetric particles, duality is vital, as an antiparticle has the opposite electric charge from its whose lightest representatives could make up the Universe’s dark mat- particle. The sum of all the electric charges emerging from the emptiness ter (see next article). is, therefore, always zero, and respects the principle of conservation of That is how particles appeared in the Universe, sprung out of nothing, electric charges observed in nature. like ghosts. “This explanation gives the impression that physicists have Then, very quickly, for reasons that are not well understood by physicists, swapped one problem for another: to explain the origin of particles, they this initial process stops. The pairs of particles created during this brief use the concept of the energy in the emptiness. But where, then, does this moment of fluctuations in the energy of the emptiness are themselves energy come from? That is another great mystery of modern physics…” very energetic. Through multiple processes, these particles give rise to subsequent generations of particles. The particles will destroy themselves (1) All quotes in this article are from Rolf Landua. 8 RTD info Special Issue: EIROforum February 2007 CERN

Help from the strings

How can the nature of basic particles be defined beyond In search of unification the mechanisms presiding over their creation? Besides the standard model of particle physics – resulting from the There is an obstacle, therefore, to the description of such a particle by postulations of quantum mechanics – contemporary the standard model (see box). Moreover, at the beginning, the Universe was both extremely small and extremely massive (all energy and matter science has pinned its hopes on the totally new unifying were concentrated into a very small volume). Consequently, there too, notion provided by the highly mathematical string theory. a theory to describe the particles that predominated during that period This introduces the prospect of totally new kinds of cannot leave gravity aside. experiments at CERN. How, then, to integrate into all this the theory of general relativity – proposed by Einstein at the beginning of the last century – which revolves entirely around gravitation? “The unification of quantum mechanics he standard model – the keystone of modern physics, painstakingly and the theory of general relativity has become the real Holy Grail for put in place during the 20th century – considers elementary particles physicists. Armies of scientists are working on the issue. The most Tto be points governed by three of the fundamental interactions promising path seems to be string theory.” recognised between the particles: electromagnetism, and the strong and weak forces. This allows us to offer a description that fits very well with what happens in this world of the infinitely small. This model, however, From points to strings does not take into account the fourth interaction - gravity. Now, in quantum physics, just as light propagates itself with the help of a particle, the photon, What does this theory tell us about our world? First, it views particles not gravitational interaction must be transmitted with the help of another as points but as elements that can be compared to extremely small particle, the graviton. strings, in the order of 10-35 meters long (1 preceded by 35 zeroes, the

The ‘biodiversity’ of elementary particles

Elementary particles are, by definition, indivisible. There are two they carry a charge. For the superpartners of the fermions, the types, bosons and fermions. prefix “s” is generally used. This gives us squarks, selectrons and In the standard model, the boson family consists of four particles sneutrinos. The language of physicists has to evolve along with that direct the four interactions of nature. The photon is responsible the science itself… for the propagation of electromagnetic interaction, including light and electricity. The gluon is the boson responsible for the pro - pagation of the strong interaction which ensures cohesion in the nucleus of atoms. The W+, Z0 and W- bosons are responsible for the propagation of the weak interaction which explains, for example, radioactivity. All of these bosons have been observed by particle physicists, unlike the graviton, responsible for the propagation of gravitational interaction, and a possible Higgs boson, which would be responsible for the mass of particles. The fermion family is divided into three sub-families. The first constitutes ordinary matter and is made up of electrons, electron neutrinos and up and down quarks. These quarks are the elementary particles that make up protons and neutrons which, in turn, make up the nuclei of atoms. The two other fermionic families of elementary particles each contain four particles that existed only at the moment of the Big Bang. Their existence can be demonstrated only under high-energy radiation. The standard model therefore contains seventeen elementary particles. This number is doubled in string theory since super- symmetry associates a fermion to each boson and vice versa. To name the supersymmetric partners of bosons, physicists generally Simulation of the decay of a Higgs boson to two jets (centre) append the standard model boson name with the suffix “ino”. and two electrons (lower left) in the CMS detector of LHC at CERN. The lines denote the particles produced by the Therefore, the photino and gravitino are introduced, whereas the collision of a pair of ultra-high-energy protons. The energy + - superpartners of W and W bosons are called charginos, because deposited by the particles in the detector is shown in pale blue. © CERN CERN RTD info Special Issue: EIROforum February 2007 9

Four interactions, from one single interaction

Another question puzzling scientists concerns nature's four famous fundamental interactions (1). Why are their strengths so different from each other? The strength of gravitational interaction is, for example, much weaker than that of electromagnetic interaction. Proof of this is that the magnetism from a single magnet is sufficient to pull a relatively large metallic mass while an entire planet is required to move the same mass using gravity. “One answer to this question is that all fundamental interactions were just one interaction at the extremely high energies which prevailed at the beginning of the universe. Just as water becomes ice at a temperature lower than freezing point, it is only when the energy of the universe was low enough that this unique interaction was divided into four different interactions as we know them today.” This unification of fundamental interactions at high energy is also explained by string theory (though this is not the only theory that is able to do so).

Seven dimensions

One of the most spectacular theoretical advances in strings is without doubt the existence of dimensions other than the three spatial dimensions (height, width, length) and time. Actually, in order to be made mathe- matically sound, string theory requires the existence of seven additional Simulation of the signature of a neutralino in a particle detector. spatial dimensions (just as a surface can only make mathematical sense in The different curves show the tracks of the particles accompanying two spatial dimensions). Matter, and the weak and strong electromagnetic the neutralino emission. This supersymmetric particle could be the dark interactions are confined to the three usual spatial dimensions. These matter astronomers are so eager to find. © Norman Graff. interactions are primarily those that help us understand the world (for example, electromagnetic interaction with light). They do not, however, give us the ability to perceive the seven other spatial dimensions, which remain ‘invisible’. Thus the lives of particles, emerging from the quantum emptiness first being to the left of the decimal point). These strings vibrate and the during the most energetic phases of the Universe. Physicists today manner in which they vibrate corresponds to different types of particle. describe them as minute vibrating strings opening up the path towards The more a string vibrates, the more energetic its corresponding particle. the unification of general relativity and quantum mechanics. It might be One of the properties of string theory that is necessary for its mathematic possible in years to come to use the LHC to verify the existence of certain consistency is supersymmetry. To understand what this is, a short elements of this theory, such as the existence of supersymmetric particles, explanation of the ‘zoology’ of elementary particles is needed. Quantum giving string theory more credibility without, however, proving it right. bodies in the universe can be divided into two families: on the one hand, there are the fermions which include electrons and quarks; on the other, there is the family known as bosons, which include the mediating particles of fundamental interactions such as the photon, which directs electro - magnetic forces, and the graviton, mentioned above, for gravitation. (1) Electromagnetic interaction, gravitational interaction, and weak and strong interactions. The supersymmetry issue

Supersymmetry consists of the supposition that each particle in the fermion family corresponds to a particle belonging to the boson family, and vice versa, hence the idea of symmetry. No supersymmetric particle has yet been discovered, but particle physicists hope to see them in high-energy collisions, which they will soon produce using the LHC, the new particle accelerator at CERN (see page 10). In the meantime, astronomers might indirectly observe the effects of these mysterious particles, since the total mass of the galaxies and galaxy clusters seems much greater than the luminous mass (stars, gas, etc) detected by astronomers’ telescopes. They therefore postulate the existence of an invisible dark matter that only interacts with the rest of matter by its gravitation, and consists of very stable, and therefore very light, particles. There are many features shared with the lightest of For more information supersymmetric particles. These could, therefore, be the unknown http://superstringtheory.com/ constituents of dark matter, the effects of which were first observed by http://en.wikipedia.org/wiki/Virtual_particle the Swiss astronomer Fritz Zwicky in 1933. http://en.wikipedia.org/wiki/Vacuum_energy 10 RTD info Special Issue: EIROforum February 2007 CERN

In 2007, the most powerful particle accelerator ever built, CERN’s new Large Hadron Collider, will probe the secrets of matter in the energy states prevailing in the moments after the Big Bang. By colliding particles together when they are moving at close to the speed of light, physicists hope to find out about matter in its earliest forms, using the energy produced by the collisions.

The promise of the large collider Antimatter. Supersymmetry. Higgs boson. Quark-gluon plasma. Many mysteries emanate from the more energetic periods of the universe, within the furnace of the Big Bang. Mysteries that researchers hope to solve with the help of the incredible time machine that the LHC will be. At this point, the first magnets of the LHC have been installed, but not connected, in the tunnel which has a circumference of 27 km. © CERN

Simulation of the collision of two The CMS detector just prior to closure. Installation of crystals on one Mounting the scintillating tiles protons in the ATLAS detector. The five barrel wheels and the six end of the modules of the ALICE photon in the LHCb Hadron calorimeter. © CERN cap discs have been slid against each spectrometer. © CERN © CERN other to start tests on the magnet and track cosmic rays. © CERN

hat is expected from the enormous investment made by Europe From the search for supersymmetry… in the production of the LHC? It will throw two beams of protons, Wparticles forming part of the atomic nucleus and belonging to Certain detectors will be capable of collision analysis. Two of them are the hadron family, in opposite directions round a circular underground called CMS (Compact Muon Solenoid) and Atlas (A Toroidal LHC tunnel of 27 km circumference beneath Switzerland and France. Apparatus). They will concentrate on the detection of supersymmetric Intensive magnetic fields are required to accelerate the protons and make particles and Higgs bosons. sure they are enclosed in narrow beams. These fields will be produced by What about supersymmetry? Particle physics consists of numerous superconductors, materials that are able to conduct electricity with neither symmetries – for example, matter and antimatter. Supersymmetry asso- resistance nor energy loss and which function at very low temperatures, ciates a fermion (building blocks of matter like electrons and quarks) to developed in collaboration with European industry. each boson (directing transmission of interactions like the photon) and vice Collisions between protons occur at a rate of eight hundred million times versa. The challenge is that the antiparticles termed supersymmetric (also per second at a colossal energy of 14 TeV. To understand the magnitude designated sparticles) have never before been observed. of this number, 1 TeV is the approximate amount of energy used for How to detect them? Paradoxically, by their absence! “It’s a little like motion… by a mosquito in flight. In the LHC, however, this energy will being at the cinema. You count the number and type of people who be concentrated in an area one million million times smaller than the enter and those that leave. If a person is missing at the end, then insect. Since the energy can be converted to particles in accordance because you know who entered you can make a guess at who did not exit.” with the principle of mass/energy equivalence in restricted relativity – In the same way, LHC testers know that certain collisions are supposed to the famous E = mc2 – physicists hope to create particles that have never produce these sparticles, which are invisible to all detectors. Knowing before been observed in accelerators. The density and intensity of the the energies of the particles prior to collision, they will be compared to collisions are important, as they multiply the chances of seeing the the energies of the particles produced after the collisions. If there is any appearance of the particles. Two beams of lead nuclei will also be difference in energy, then a particle has escaped. By calculating the produced, reaching energies of 1 150 TeVs, but with fewer collisions missing energy, they will know if a supersymmetric component or per second. sparticle is involved. CERN RTD info Special Issue: EIROforum February 2007 11

…to that for the Higgs Boson This is where the question arises that the LHCb will attempt to answer: where, then, is antimatter? One possible answer is based on the ability The other challenge for the CMS and LHS detectors is to detect the of certain particles to transform themselves into their antiparticles and vice Higgs boson. The focal point of the standard model theory, this is versa. In this case, the existence of matter depends on the hypothesis – supposed to interact with the particles and give them mass. How? Let’s yet to be proven – that the transformation of antiparticles into particles consider a room full of physics students. Suddenly, Albert Einstein is dependent upon the opposite transformation at the beginning of the enters the room and the students surround him and press him with their universe. The annihilation process of matter and antimatter would questions. Albert, then, in his attempts to move, feels a certain inertia due eventually have brought forth a universe where matter prevailed over to the students that are clinging to him. He is similar to these particles anti-matter. when Higgs bosons try to interact with them – they gain mass. Here too, Can such disequilibrium be demonstrated? It has actually been seen the much anticipated detection of these famous bosons can only be experimentally with quark-type particles called kaons. Antikaons indirect: the particles that result from their disintegration are the ones spontaneously transform into kaons but the opposite occurs less often. that will be detected. The LHCb will study another candidate, meson B, which contains (among other things), an elementary particle (or its antiparticle) called quark b, or beauty (from whence the charming name of the LCHb). The quark-gluon soup

The third detector with which the LHC is equipped is named Alice (A Large Ion Collider Experiment). Its purpose is to explore the unknown sections of nuclear physics, especially a state of matter that existed a very short time after the Big Bang known as quark-gluon plasma. What is this new oddity? In the 1960s, scientists realised that the protons and neutrons that make up the nucleus of atoms, were themselves made up of more basic particles, quarks. These quarks are linked to each other by strong forces, themselves directed by particles known as gluons. One of their characteristics is that they are gregarious: they always go in pairs or in threes; they cannot exist by themselves. The more you try to separate a quark from another quark, the greater the cohesive force that binds them together, making them permanently For more information inseparable. Quarks are said to be confined. However, if protons are ATLAS: http://atlas.ch/ bombarded against each other at high energies, a soup is created CMS: http://cms.cern.ch/ containing quarks and gluons in which the quarks will be free to move. ALICE: http://aliceinfo.cern.ch/Public/index.html We can then refer to the deconfining of the quarks in the quark-gluon plasma. Why this deconfining? “It is a little comparable to skiing. When there isn’t much snow, the tracks can be separated by grassy zones and the skiers are confined on their tracks. On the other hand, if there is a lot of snow, they can change tracks. They are deconfined.” Rather than snow, physicists will add energy: the greater the quark energy, the weaker their cohesive forces, so above a certain energy threshold, they can be separated. The tracks of the particles This quark-gluon plasma state was probably the state of matter a few microseconds after the Big Bang. That is why physicists wish to study Though particles cannot be seen, it is possible to detect them. it with the help of lead-ion beams produced by the LHC. These are, in To do this, the LHC is equipped with devices consisting of effect, very rich in protons and neutrons. They can attain an energy of several concentric layers which, like an onion, surround the 1 150 TeV which is required to produce and study the quark-gluon particle beam where the collisions occur. Each layer specialises plasma present at the beginning of the universe with unprecedented in one particular type of detection. precision. • At the centre of the detector, there is a track chamber. Inside this chamber, there are millions of semiconductors The mystery of antimatter that produce an electric pulse when touched by a particle. These pulses are recorded by computers. This makes Finally, the last detector, named LHCb, the Large Hadron Collider it possible to reconstruct their trajectories. beauty. Its goal is to better observe the subtle differences between matter and antimatter in order to better understand what happened to the • There is also a magnetic field inside each detector. This Universe's antimatter. helps detect and study the trajectories of the charged For each particle, there is an antiparticle that has, among other properties, particles, such as the electron or the proton, which are the same mass but an opposite charge. Therefore, for the negatively sensitive to the magnetic field. charged electron, there is a corresponding antielectron (or positron) of equal mass but with a positive charge. When an electron and an anti- • Another device is a calorimeter-bearing track detector. electron meet, they annihilate each other, producing a burst of energy. Some calorimeters stop particles like photons or electrons, According to the standard model of particle physics, equal amounts of while some are designed to stop neutrons and photons. matter and antimatter must have been created at the beginning of the They measure the energy lost by the particles that universe. Consequently, all particles should have cancelled each other penetrate them. out and the universe should be empty. However, as anyone can see, matter is abundant. 12 RTD info Special Issue: EIROforum February 2007 EFDA

All eyes are

on ITER The Cadarache site, in the south of France, with a mock-up of the ITER facility. The new reactor should be operational by 2016. © ITER

Backed up by the unique expertise it has acquired on JET – the most advanced experimental fusion machine in the world – Europe has succeeded in bringing together a wide international consensus regarding the realisation of ITER. The launch of this new reactor is mobilising enormous scientific and technological cooperation involving scholars and engineers from all over the world. At the European level, this collaboration is firmly structured and placed under the auspices of EFDA (the European Fusion Development Agreement).

onstruction of ITER – which represents an investment of 4.5 billion The European fusion umbrella euros – should commence in 2007 at the Cadarache site, in the Csouth of France. This new fusion reactor, operational in 2016, should Although the construction and operation of JET – and the unique prove whether or not mankind can count on this extraordinary energy knowledge regarding fusion this has produced – has been one of the resource, which combines the promise of being unlimited, safe, essential driving forces behind the launch of the new ITER reactor, fully controllable, clean (no waste products) and with no it has also been the melting pot for scientific cooperation harmful effects on the climate. which is now unified and firmly structured at European Since the 1950s, several European countries level. This is covered by EFDA (the European Fusion have started to show an interest in the Development Agreement). energy prospects of nuclear fusion and This body brings together and coordinates all have financed research in various funda- research resources devoted to fusion in mental physics laboratories at national 22 Member States, as well as programmes level. Moreover, at Community level, the implemented by the European Commission 1957 Euratom Treaty, which defined in this field. EFDA is, in fact, the Project a common policy in the nuclear sector, Manager for the JET operation, and its included the willingness to establish facilities should provide an especially close scientific cooperation for the well-suited test bench for evaluation and development of knowledge and validation of the complex technologies technology in this futuristic field. needed for the development of ITER. Under the aegis of the European Supervision and management of EFDA Union, this climate of active collabo- are ensured by support teams (Close ration established between scholars Support Units), based at Garching, near and engineers throughout the whole of Munich (DE), and at JET. At Garching, all Europe resulted in the emergence and research activities spread over the 29 or so realisation of the fusion reactor known as fundamental physics organisations and institu- JET (Joint European Torus) at the Abingdon tions working on the development of fusion in site, just outside Oxford (UK). Thanks to this Europe are coordinated. The number one priority is, state-of-the-art machine, the most important of its of course, the scientific and technological contribution type in the world, progress made over two decades has that the European Union and each of the members of the contributed to top-level scientific and technological expertise regarding organisation are committed to making to the ITER project. the achievement of the extremely complex conditions for fusion. These are marked by the enormous constraints of the mind-boggling temperature levels (reaching over 100 million degrees!) that are required for fusion to take place within a confined hydrogen plasma. For more information www.efda.org/ www.jet.efda.org www.iter.org EFDA RTD info Special Issue: EIROforum February 2007 13

A calculated gamble

A specialist in plasma physics, David Ward is a member of David Ward – “I would never suggest that the UK Atomic Energy Authority involved in the preparation nuclear fusion was a ‘magic’ formula capable, of ITER at the Abingdon (UK) centre. He is convinced that on its own, of resolving future energy problems. All renewable sources – and this is one of fusion can and should become a major source of energy for them – must be mobilised.” meeting the needs and climatic constraints of the 21st century.

Having been fully studied, discussed and negotiated for almost twenty ITER, along with the International Space Station, represents one of the years now, ITER is an incredible gamble on a scientific and technological most expensive scientific investments ever undertaken. Does Europe outcome, the validity of which will not be substantiated for at least another have the resources for this? ten years. Is it really worth the price? The cost of construction and operation of ITER – 12 billion euros – is, It may still be looked upon as a kind of gamble, but rarely has a gamble first of all, shared among seven partners. The contribution made by been taken on the basis of data that has been so seriously considered, Europe, which welcomes the reactor on to its soil and will, thanks to its calculated and evaluated. Hundreds – if not thousands – of scientists experience, be one of the key players in this international scientific from all over the world have analysed the odds afforded by the project cooperation, amounts to 40%, which is to say, some 5 billion euros. For and have managed to convince seven major powers, among the most the purposes of comparison, investments envisaged for fusion – which are important ones on the planet, to establish a common partnership for its spread over 12 years – represent 1 billion euros per annum. In parallel, realisation. expenditure on renewable energy amounts to 40 billion euros per annum. And if there is still a risk – of course not one of failure, but possibly one The world energy market is put at 4 000 billion euros per annum. of a shortfall in results in terms of objectives – is it not still worth taking, considering the energy challenges facing us? As from the 2020s, the Fusion is therefore only one of the energy solutions for tomorrow’s world. planet will be inhabited by some eight billion human beings, compared What are its specific advantages? with six billion at the present time. Already, with the surge in economic I would never suggest that nuclear fusion was a “magic” formula capable, growth of countries like China, India or Brazil – the first two of these on its own, of resolving future energy problems. All renewable sources being partners in ITER– and not forgetting the enormous needs of the – and this is one of them – must be mobilised. Fusion is, to my mind, rest of the developing world, worldwide consumption of energy is increa- one of the rare future options likely to meet the large-scale energy needs sing and will double over the next two decades. This trend goes hand in of the countless urban metropolises that are springing up all the time hand with what is now known for sure: the present rate of use of fossil on all continents. fuels cannot be maintained. This is both because of climatic reasons Fusion now a scientific and technological process that we absolutely and because, for future generations, resources will be exhausted. must learn to master. All advances in know-how acquired over decades show that it is worth proceeding along this path. It is not, of course, simply for the pleasure of performing an amazing feat. JET was constructed in the 1970s, because of the grave warning represented by the first petroleum crises. Then the tense situation regarding petroleum subsided for more than twenty years, resulting in the ITER project becoming long and drawn out, although it was still being studied as a concept. Nowadays, we are seeing not only a new petroleum crisis, but we are also concerned about what is to happen in post petroleum times, and about global warming. This is what is really at stake with ITER. To use your own words, I have no doubts about it being “worth the price”.

Contact David Ward [email protected] Fusion reaction. © EFDA 14 RTD info Special Issue: EIROforum February 2007 EFDA

The ambitious adventure of fusion

Half a century ago, physicists began to imagine that the stellar nucleosynthesis model could be reproduced on Earth providing an inexhaustible source of energy. RTD info takes a look at this long scientific quest, in which Europe has played a leading role, one it still continues to play with the new crucial stage of constructing ITER. When hydrogen is converted to plasma, it is characterised by a gaseous mass of hydrogen ions, i.e. positively charged nuclei. Research into more hen the Universe was only a few minutes old, the only element spherical fusion plasma configurations is being carried out by the British was hydrogen. It then took approximately one billion years Mast experiments fusion programme, the successor to the Start programme. Wfrom the Big Bang for the stars to be born. Their formation was © EFDA brought about when large clouds of drifting hydrogen started to collapse under the effects of gravity. This contraction was accompanied by an extraordinary cumulative rise in temperatures, during which the hydrogen was transformed to its plasma state: the increase in temperature The interest in nuclear fusion also stems from the fact that it eliminates separated the electrons from the nuclei to which they were attached, the risks associated up until now with the civil use of atomic energy. so that this plasma state was characterised by a gaseous mass of Unlike the process of fission involving heavy uranium atoms, on which hydrogen ions, i.e. positively charged nuclei. nuclear facilities spread throughout the world have relied to date, fusion This coexistence of positive ions would seem to entail electrostatic cannot form the basis for any chain reaction, like that which occurred repulsion, keeping them apart from one another. But if the temperatures at Chernobyl. It does not call for the removal or reprocessing of any continue to rise within the plasma, the electrostatic repulsion is replaced radioactive waste; the only radioactivity produced, with a lifetime limi- by the triggering of a strong nuclear interaction. Its duration is very short, ted to just a few decades, is contained within the internal walls of the but it is extremely powerful. Suddenly, and irresistibly, two nuclei are reactor. Lastly, nuclear fusion could provide an important alternative to attracted to one another under the effect of this force, which causes the use of fossil fuels which, at a time when climate change is on the them to fuse. This fusion of hydrogen nuclei (with an atomic weight of one) agenda, is a huge advantage. produces helium (atomic weight of two) the second element that appeared in the Universe. At the same time, the loss of mass resulting from this process is transformed into an enormous release of energy. This A 100-year journey contributes to keeping the fusion phenomenon alive (1). But although the actual equation for the fusion of two atoms is disconcer tingly simple, involving the simple addition of a few hydrogen The dream of scholars nuclei, the long process of research into fusion carried out over the last fifty years has still not achieved its goal. According to reasonable estimates In this way, the myriads of stars that make up the Universe were born. that can be made now that the decision to construct ITER has been They exist as melting pots with an incredible capability for the production taken, its goal – which will only be achieved when industrial exploitation of matter and energy via fusion, starting, of course, with our own Sun, the of fusion for energy purposes begins – will require another fifty years. primordial purveyor of energy to Earth. The real challenge is still to “reproduce the Sun on Earth”, which means But ever since science discovered the principles of stellar nucleosynthesis bringing about a process that can only take place at temperatures that – towards the middle of the last century – an ambitious dream began to defy the imagination, i.e. at around 150 million degrees. take shape in the minds of physicists: if we managed, here on Earth, to First, researchers had to choose the ‘fusionable’ atoms. Out of all the reproduce and technologically master the process of nuclear fusion, possible reactions, the fusion of deuterium and tritium (two, readily mankind would then have an unprecedented and almost inexhaustible available, heavy isotopes of hydrogen) was chosen. The main natural source of energy. reservoir for deuterium is the oceans, from which an average of 35 g This potential abundance is based on a twofold premise. Bringing about of deuterium can be extracted for each cubic metre of water. Tritium, on a fusion reaction with an instantaneous energy output comparable with the other hand, a radioactive element whose half-life is around 12 years, that of a major power station could be realised using plasma containing is extremely rare in nature, but can easily be produced within a fusion just a few grams of heavy hydrogen ions (2). Then again, hydrogen is the reactor, using lithium – a light metal that is abundant in the earth’s crust. most basic and most abundant element not only in the Universe, but also In order to make a fusion reactor work, extremely low quantities of these on our planet, starting with its presence in water. two basic fuels are necessary. By way of example, an industrial fusion EFDA RTD info Special Issue: EIROforum February 2007 15

reactor with a capacity of one gigawatt would only require 100 kg of deu- terium (extracted from 2 800 tonnes of sea water) and 150 kg of tritium (which can be produced from 10 tonnes of lithium ore) each year. The fundamental problem, however, which still has to be resolved by ITER, is the effective triggering of a lasting fusion reaction within the peculiar gaseous mass formed by a plasma heated to extreme tempe ratures, which is particularly difficult to maintain in a stable state. The sine qua non condition is that the plasma has to be enclosed and not have the sligh- test contact with any part of the reactor walls within the chamber where the hydrogen ions circulate at increasing speeds until they meet and fuse. Realisation of this condition is known as plasma confinement.

JET, the first machine

Here, too, choices have gradually been made. The reactor identified as being the most efficient is the tokamak type reactor, put forward in the 1950s by the Russian scientists, Igor Tamm and Andrei Sakharov. Its name is the Russian acronym for a container in the form of a torus, in which plasma is confined within the walls, using powerful magnetic fields. Several tokamaks exist in the world, but the largest and most successful one ever built is the Joint European Torus, or JET. In this experimental reactor, designed during the 1970s and operational since 1983, it has The ITER divertor operational test platform. Operation of this been possible to study and fine-tune the most advanced techniques for essential part of the reactor, which allows for the loading of fuels heating, confining and controlling the stability of plasma. It was in the core and removal of fusion waste (in the form of non-radioactive helium) of JET that, in 1991, it was possible to trigger the first controlled fusion has to be completely remote-controlled. © ITER reaction realised on Earth. The release of energy was hardly spectacular – less than 2 megawatts – but a substantial step forward had been taken. Patience and repeated tests carried out by researchers allowed the achievement in 1997 of a record unequalled in terms of fusion The ITER path energy power: 16 megawatts. This achievement was, of course, just a flash lasting a few seconds, only 24 metres high and 30 wide, ITER is designed to produce 500-700 MW of reaching a factor of 0.64 of the sacrosanct ‘break-even’ threshold, the thermal power, within a toroidal fusion plasma with a volume of 800 m3, crucial point at which fusion energy exceeds the amount of energy nee- confined using powerful magnetic fields. It has to produce between five ded to heat and confine the plasma. It is this barrier that the ITER toka- and ten times more heat than is necessary to maintain the plasma at mak will have to break through in a convincing manner. fusion temperature. It will thus show that sustained and reliable energy production is possible, with a view to achieving continuous operation of a power station. The path will then be open for physicists and engineers to develop and optimise the technologies, components and control strategies that will be used in the future in a demonstration fusion-powered, electrical power station - the final stage in this century-long process. It has already been given a name: DEMO.

(1) All elements in the Universe, from the lightest (such as carbon and oxygen) to the heaviest (gold, lead or uranium), have been formed by a series of nuclear fusion reactions involving light atoms, first at the centre and then in the outer layers of stars. (2) It may be assumed, for example, that one kilogram of ‘fusion fuel’ generates as much energy as 10 000 tonnes of coal in a traditional power plant.

Plasma confinement. This is ensured by the field produced by a complex system of electromagnetic coils. © EFDA 16 RTD info Special Issue: EIROforum February 2007 EFDA

JET, the pioneering test bed for ITER

The Joint European Torus (JET) reactor may be thought of as the pioneering machine without which the ITER project would never have seen the light of day. This state-of-the-art centre is one of the test rigs on which the validity and feasibility of numerous scientific and technological options considered for the future international reactor at Cadarache, have been assessed.

One of the research departments at Abingdon is working on the development of maintenance robotics which will be needed to enter the radioactive chamber of the ITER tokamak and carry out checks and operations within it. The robot in service on the JET machine has the flexibility of a snake: it spreads out within the toroidal chamber until it reaches all the way around. Steering is controlled remotely from a small room filled with screens, where the operator delicately manipulates two control knobs. The steering system allows the resistance of even the smallest screw to be felt.

ased at the Culham Science Centre near Abingdon, in rural A new chamber Oxfordshire (UK), the JET facilities constitute the flagship of the BEuropean fusion programme. “Other research laboratories based on “In terms of its size and configuration, the JET machine is the largest the continent have their own experimentation facilities,” Chris Carpenter, ‘scale model’ on which numerous developments required for construc- the representative of the UK Atomic Energy Authority, which forms part tion of the Cadarache reactor can be tested and validated,” explains of the EFDA, explains. “But JET constitutes the most versatile and best Shakeib Arshad, representative for the Close Support Unit responsible equipped test bed for testing and validating a large number of tasks.” for the scientific strategy of the reactor. “Thanks to constantly improving diagnostic methods, we are able to work on deuterium/tritium plasmas with different forms and temperatures, seeking to optimise the energy When the reactor is switched on performance of each of these methods. Other strengths of the JET machine relate to control of the flow of rapid alpha particles, which The Culham Science Centre is home to hundreds of researchers and transmit their kinetic energy to other particles in the plasma.” engineers, both residents and visitors, from Europe and other continents. In 2007 or 2008, experiments will be interrupted for several months, When the reactor is activated to carry out various experiments, the allowing the machine to be upgraded. “Often, after a series of experi- control facilities for JET resemble the launch control room for a rocket going ments, we modify the infrastructure so as to allow for new test configu- into space. On their screens, some fifty or so experts monitor thousands of rations. But this time, it is a matter of major work, which will enable us variables that affect machine operations, plasma behaviour, temperature, to try out a new internal chamber. This will be made of the beryllium magnetic confinement, etc. cladding chosen to cover the walls of the future ITER reactor – instead On a central stage, three people, representing those responsible for the of the carbonaceous composites used up until now in the tokamak. This experiment in progress, full-time physicists for the JET programme and new configuration will be a world first. Compatibility between the plasma engineers responsible for operating the technological equipment, over- and this chamber constitutes, of course, a fundamental gamble for the see operations. “The deuterium/tritium plasma confined in the tokamak project. New challenges await us.” is lighter than air. It is made up of a million times less particles than the atmosphere, but is a million times hotter,” explains Christopher Warrick, physicist and spokesperson for the JET. “We have spent years learning to manage the incredibly extreme and unstable situations that appear in a physical environment like this.” The teams work in shifts, from seven in the morning until ten at night. Suggestions regarding experiments are defended before a European scientific committee by each of the seven task forces for the JET programme. They are analysed with a fine-tooth comb, specifically in terms of the relevance of the experiments for the deployment of ITER. For more information www.jet.efda.org ILL RTD info Special Issue: EIROforum February 2007 17

Neutrons in the service of science

Institut Laue-Langevin (ILL). The name given to ILL by its founders pays homage to two pioneering physicists from the last century (1). This European centre of excellence is currently one of the most important sources of neutrons anywhere in the world; thanks to these, researchers in all disciplines can study the structure of matter, whether inert or living.

his important scientific facility was set up in Grenoble in the 1960s, the brainchild of the German physicist Heinz Maier-Leibnitz and his French colleague Louis Néel, who received a Nobel Prize in T Cerenkov effect visible in the ILL reactor pool. The blue light stems from 1970 for his work on magnetism. Together they wanted to make the a phenomenon of water polarisation when high-energy electrons pass incredible atomic- and molecular-research tool afforded by neutron through it. These electrons are created by gamma rays produced by the beams available to civilian basic research. This French/German pairing fission process in the reactor core. has been strengthened by the equal participation of the United Kingdom © ILL/Jean-Luc Baudet since the 1970s (2). Since then, other partnerships with different European countries have provided their support for the institute.

A world leader Teaching aids

As the world leader in neutron science and technology, ILL is a service ILL keeps in touch with the general public via a series of thematic institute offering researchers from all over the world the possibility of brochures (in English) on technological neutron applications in different carrying out research in a wide range of fields – from condensed matter fields (matter, life, new materials, the Universe, etc.). Very clearly illustrated, physics to materials science, chemistry, biology and nuclear physics. these downloadable brochures constitute interesting learning aids for Each year, around 2 000 researchers, selected by a scientific committee, teachers. spend time there on their own projects, and some 800 experiments are carried out. In parallel, the scientific life of the institute itself and support for its users involves more than 300 researchers, engineers and technicians (1) The German Max von Laue (Nobel Prize 1914) was the inventor of the system on a permanent basis. The outstanding excellence of the ILL is due to the for measuring the wavelengths of X-rays by diffraction through a crystal, and the quality of its neutron source, but also to the large number of beamlines Frenchman Paul Langevin was an important researcher in the team of atomic over which these are distributed. Consequently, any one neutron source pioneers that surrounded Pierre and Marie Curie. The two of them may be can be utilised for various experiments calling for very different beams, considered as being the “spiritual fathers” of neutron research. in terms of both intensity and energy. Apart from detectors and various (2) Apart from the three Associate Countries, scientific partnerships have been instruments, sophisticated equipment – designed and developed by formed continually over the last twenty years or so: Spain (1987), Switzerland “in-house” scientists and often unequalled anywhere in the world – is (1988), Austria (1990), Russia (1996), Italy (1997), Czech Republic (1999), also available to researchers. This consists of state-of-the-art optical Sweden and Hungary (2005), Belgium and Poland (2006). components: monochromators; supermirrors which reflect, concentrate and guide neutron beams; cryomagnets used to study samples in the magnetic state required, etc. For more information www.ill.fr www.ill.fr/pages/science/AtILL/brochures.html 18 RTD info Special Issue: EIROforum February 2007 ILL

Is energy 2

really equal to mc ? © Photo Library at Palais de la Découverte [Paris Science Museum]

Devised by Albert Einstein in 1905, the special relativity Subsequently, other experiments have been carried out by causing an equation E=mc2 – the most famous formula in modern electron and a positron (a pair of antiparticles) to collide. On collision, physics – has established the basis for equivalence between they are destroyed, and by comparing the energy released to the original mass of the particles the attempted verification can be made. Physicists energy and mass in the space-time continuum. Even if no admit, however, that this method of measurement remains unsatisfactory. new theory or observation has invalidated this fundamental It was only in 2005 that the ILL’s neutron flux facility enabled a verification equation, physicists are constantly trying to prove it by method to be perfected that was 55 times more precise than ever before. means of experiments. With a precision that has never been achieved before the latest of these has taken place at Gamma rays and measurement of mass the Institut Laue-Langevin (ILL) in Grenoble, the European – and indeed world – centre for neutron science: the very In order to undertake this demonstration, which was closely monitored special branch of nuclear physics that uses neutron beams throughout the world of physics, researchers separately measured the to explore the fundamental building blocks of matter. two elements of the equation: mass on one side and energy on the other. How is this achieved? When a nucleus captures a neutron, it produces a miniscule quantity of energy in the form of a gamma ray. This energy, referred to as binding energy, corresponds to a proportional loss of ubstantiating Einstein’s theory with sufficient precision is not an mass. The experiment therefore consists of measuring this disappearing easy thing to do. In 1932, a British team was the first to take up mass and comparing it with the energy of the ray produced. Sthe challenge, using protons to bombard a lithium screen which It was at the Massachusetts Institute of Technology (MIT) that the measure - disintegrated, releasing high-speed helium nuclei. By measuring the energy ments of mass took place, using a device known as a Penning Trap. The of these nuclei and comparing it with the difference in mass between the weighing procedures related to the difference in mass between a initial nuclei (lithium) and the resulting nuclei (helium), researchers were silicon-28 nucleus and one which had captured a neutron (i.e. silicon-29). able to confirm that the equation “worked”, but this confirmation was This difference is obtained by comparing the frequency of rotation of the still marred by a margin of error of several percent. two atoms, which are made to turn in a magnetic field of 8 teslas.

The GAMS 4 Gamma ray spectrum used by the ILL for verification of Einstein’s equation. © ILL/Artechnique ILL RTD info Special Issue: EIROforum February 2007 19

The neutron, workhorse of the subatomic world A mass of 1.68x10-24 grams, a “size” of 10-15 metres (1 fermi), zero electrical charge, a magnetic spin of 0.5. The neutron, together with positively charged protons, is one of the components of the core of an atom. During controlled nuclear fission reactions, radioactive decay releases these subatomic particles which are totally “neutral”, which is to say, not only electrically neutral but also devoid of ionising power. Scientists have been quick to appreciate the extraordinary tool Michael Jentschel: "Our experiment is the afforded by the neutrality of these fundamental particles of the equivalent of making a 2 mm cut, from Paris, atomic world. When neutrons are fired in a beam at a “target”, in an apple located in Moscow." they penetrate its atoms in a non-destructive way, observing © ILL/Serge Claisse them in great detail. Their mass causes them to “bounce back” off the atom nuclei, and these impacts are reflected in wave This result is then subtracted from the mass of a neutron, which gives emissions and energy exchanges. the small difference in mass corresponding to the energy produced by Two major types of detection apparatus allow extremely detailed the gamma ray. For Simon Rainville, the MIT lecturer in charge of the information regarding the matter studied to be analysed and experiment, “This is the most accurate measurement of mass in the world - one part per 100 billion.” The right-hand side of the equation (mc2) is thus evaluated by multiplying this value by the square of the speed of light.

Measuring energy

Meanwhile, on the other side of the Atlantic, a group of researchers from NIST and ILL had been concentrating on calculating the left-hand side of the equation (energy, E), by measuring the energy of the gamma ray using a gamma-ray spectrometer. In this case, the silicon-28 atom is bombarded with neutrons. When it captures one, the gamma-ray produced is diffracted by two ultra-pure silicon crystals, which deflect The D19 thermal neutron diffractometer allows the matter studied it in accordance with an angle proportional to its wavelength, and therefore to be analysed. This apparatus identifies the characteristics of atomic its energy. The angle is measured with a precision of around five ten mil- waves emitted when the matter has a neutron beam passed through it, lionths (5x10-7) using an angular interferometer specially constructed for and therefore allows the position of the atoms in the sample analysed the experiment. According to Michael Jentschel, an ILL physicist involved to be reconstructed. © ILL/Artechnique in this state-of-the-art research, the precision of this measurement “is the equivalent of making a two-millimetre cut, from Paris, in an apple extracted. The neutron diffractometer identifies the characteristics located in Moscow”. The energy of the gamma ray thus determined (direction of propagation, wavelength and amplitude) of the defines the value for the first element in the equation. atomic “shock waves” produced when the neutron beam passes The calculation was successful and E is verified as being equal to mc2, through the matter. This information allows the structure and with an accuracy of 0.00004%. “The converse would, quite simply, position of the atoms in the sample to be reconstructed. have turned the world of physics and cosmology upside down,” Michael Secondly, neutron spectrometry allows the energy exchanges Jentschel explains. “And the first reaction would have been to question that are caused to be measured by providing information on the validity of our work …” That is how it is with science, which quite often energy distribution and, consequently, on the movement of the consists of measuring values that cannot be other than those anticipated. atoms being observed. “Our experiment was not, therefore, a major event for the media. Moreover, the spin inherent in the neutron makes it sensitive to We know that the official and universal standard of mass is still defined the magnetic properties of the atoms it passes through. In fact, by a platinum-iridium cylinder carefully preserved at the International it constitutes the only probe capable of ‘seeing’ both atomic Bureau of Weights and Measures in Paris. The interesting aspect of our work nuclei and the magnetic mechanisms of their electrons. lies in the experimental innovation of linking mass to another physical Complementing other sources of radiation, neutrons excel in quantity, energy.” fields of expertise that afford them a unique place at the centre of scientific and technological challenges facing tomorrow’s world. They cover particularly varied and extensive fields of research, in particle physics, nuclear physics, chemistry, biosciences and materials sciences. 20 RTD info Special Issue: EIROforum February 2007 ILL

Mars. Galle Crater, to the east of the Argyre Basin. © ESA

Topographical map of Mars. In grey: curves relating to pressure levels, defined by calculation, as distributed around the vast Hellas and Argyre craters following impacts. Black lines: contour of magnetic fields measured The mystery by the Global Surveyor probe. © Projection Mercator. Courtesy of MOLA science team. of Martian magnetism

On Mars an altogether different problem, bringing together Evidence in the form of pyrrhotite matter and energy, has been illuminated thanks to (Institut Laue-Langevin) ILL’s neutrons. Since 1997, when the To support such a supposition, it was first of all necessary to produce a American Mars Global Surveyor probe flew over its surface hypothesis regarding the very nature of these rocks responsible for magnetism and measure their phase transition threshold, the pressure for the first time, at an altitude of 400 km, scientists have at which the rock is demagnetised. From the broad range of possibilities, been intrigued by the considerable magnetic anomalies suspicion fell on the magnetic properties of an iron sulphide known by identified on the red planet. In Grenoble, researchers have the name of pyrrhotite. managed to show that fossil traces of Martian magnetism can It was at ILL that research into the magnetic transition threshold of be explained by the presence of iron sulphide, pyrrhotite. pyrrhotite was carried out using neutron diffractometers. “Fired at a sample of ore, the diffracted neutrons are collected by a detector, which displays the characteristic diffraction peaks not only of the atomic structure, our billion years ago, Mars had a magnetic field that was probably but also of the magnetic moment arrangements of the atoms,” explains similar to that of Earth. But as the red planet cooled, the iron-rich Bachir Ouladdiaf, a magnetism specialist at ILL. After increasing the Fmolten magma, whose movement – acting like a dynamo – gives pressure to between 2.6 and 3.1 gigapascals (1), researchers were able rise to a planet’s magnetic field, ceased to flow. to record the disappearance of peaks associated with magnetism. Delving into the past explains why the northern hemisphere of Mars It was then a matter of returning to the planet Mars where, thanks to the appears to be devoid of a magnetic field: its crust must have solidified information obtained using probes and simulations, geophysicists were following the end of magnetic activity at able to identify areas around the impact points that had been subjected The end of an illusion… its core. On the other hand, it appears to pressures that exceeded these thresholds. They tally perfectly with The magnetism of meteorites that the crust of the older southern the demagnetised areas identified by the Mars Global Surveyor probe. of Martian origin that have fallen hemisphere still retains ‘fossilised’ “Measurement of the phase transition of pyrrhotite allowed for an to earth on various occasions has traces of this activity. explanation not only of the anomalies of magnetic remanence of the been studied as a field of research This global magnetic cartography was, Martian crust – which was the starting point for the research – but we into the magnetism of the red however, contradicted by two anomalies were then also able to designate the pyrrhotite as being the main mineral planet. New data obtained from identified by Mars Global Surveyor: present responsible for this remanence. Sometimes, the infinitely small, work on the magnetic transition a total absence of magnetism around the neutron, allows the magnetic history of a planet to be clarified by threshold of pyrrhotite render these the vast Argyre and Hellas basins, two investigating the tiniest details of a mineral.” previous studies invalid. Indeed, ancient craters over 200 km in diameter, at the time they were ejected, hollowed out by gigantic meteorites. all Martian meteorites were subject As the rise in temperature following the (1) One gigapascal is equal to 10 000 times the atmospheric pressure on the to a pressure well above impact of these meteorites could not surface of Earth. 3 gigapascals. The absence of any categorically explain the extent of the high remanence levels in these demagnetised area, geophysicists then rocks illustrates the absence of looked into whether the cause could be a magnetic field at the moment of attributed to an increase in pressure, at impact – and not at the time the core of the rocks responsible for For more information of crystallisation of the rocks. fossil magnetism, at the time of the P. Rochette, G. Fillion and R. Ballou, F. Brunet, B. Ouladdiaf, impacts. L. Hood, Geophysical Research Letters, vol. 30, n°13, 1683 (2003). ILL RTD info Special Issue: EIROforum February 2007 21

Like a synchrotron’s X-rays, neutron beams reveal the structure of inert matter, but now biologists too are making increasing use of the research infrastructure in Grenoble to study the complex molecules that make up living matter. Very specialised work carried out in partnership between the Institut Laue-Langevin (ILL) and the European Synchrotron Radiation Facility (ESRF) relates specifically to Neural Cell Adhesion Molecules (NCAM), which are responsible for rejection or adhesion between nerve cells in the synapses. From neutrons to neurons

his research underpins major challenges at a medical level. If the The protein then becomes adhesive again. It is by affecting the salinity purpose of the adhesion mechanisms in these long molecules of the medium that cellular adhesion is controlled,” says Giovanna Tattached to the cell membrane is to ensure the stability and integrity Fragneto, a specialist in cell membranes at ILL. of connections between neurons, then repulsion mechanisms, on the This recent research into NCAMs does not yet allow for direct applications. other hand, are in charge of the migration of young cells and thus allow The knowledge relating to cell adhesion mechanisms and the proteins for development of the central nervous system. involved nevertheless appears to offer interesting prospects for the This plasticity, which is essential for its construction, also proves to be future. The research could result in treatments for neurodegenerative crucial for its reconstruction, in terms of therapeutic prospects. illnesses, such as Alzheimer’s disease, or a way to control the growth of Conversely, the migratory phenomenon of neuron cells is also an hippocampus cells on artificial structures in order to provide care for aggravating factor in brain cancers. spinal cord lesions. Certain bio-engineers hope to find clues to joining biological material and artificial prostheses. Others, conversely, dream of integrating nerve tissue within electronic equipment, to construct From adhesion to repulsion ‘biological’ computers.

To understand how adhesion and repulsion occur, scientists firstly measured the thickness of adhesion molecules. A monolayer of Neural Cell Adhesion Molecules was deposited on a film, reproducing a cell membrane. Using synchrotron radiation and neutron spectrometers at ILL and the ESRF, researchers have confirmed a result that had already been anticipated: the layer is much thinner than it should be if the seven molecule segments are aligned perpendicular to the membrane. In actual fact, the protein is folded over at a point level with its second segment, thus reducing the adhesion distance between two cells. Neutrons diffracted by the proteins have thus allowed the thickness and roughness of the adhesion layer to be measured and its composition to be determined. Once this information was confirmed, researchers were able to identify, in the adhesion mechanism, the dual role of a polysialic acid (PSA) In the image on the left, polysialic acid (PSA) plays a vital role in the polymer and the presence of sodium in the cell medium. “Two types of migration of stem cells during development of the brain. On the right, NCAM are present on the neuron membranes,” explains Oleg Konovalov, without this PSA mediator, we can observe the phenomenon of friction head of research at the ESRF. “Those associated with young cells have between cells, which impedes migration. © U. Rutishauser a PSA chain, whereas the others do not. The PSA chain inhibits adhesion by surrounding and masking the areas of the molecule that are involved. We wanted to understand the process known as repulsion, which is essential to allow newly formed cells to migrate and find their place in the nervous system.”

Through observation of matter and life, work carried out at the ILL and A question of salinity the ESRF at Grenoble’s Scientific Polygon site serves first of all to remind us that the basis for all scientific research is the observation of How do these cells attach themselves when they reach their destination? nature. It is only on this basis that laws and theories are constructed and By determining how far the NCAMs extend over the surface of the cell validated. Whether based on neutrons, X-rays or electron microscopy, membrane and measuring the space occupied by the polymer, researchers modern investigation techniques provide scientists with observation have been able to answer this question. “Normally, PSA prevents adhesion. facilities unequalled in history. At the same time, with our knowledge But, by increasing the salinity, the polymer retracts and allows areas of increasing all the time thanks to these tools, the discoveries they allow the molecule to show through, ensuring the adhesion mechanism. give rise to as many questions as answers… 22 RTD info Special Issue: EIROforum February 2007 ESRF

It was back in 1975 that the idea of building the first third-generation synchrotron in Europe, with the capacity to generate X-rays a thousand billion times more intense than those traditionally used in medicine or crystallography, was conceived. The era of new light

renoble, a city famous for science and high technology, Gwas selected in 1988 as the site for the ESRF (European Synchrotron Radiation Facility). A key factor in the decision was the presence in the city, since the 1970s, of the Institut Laue-Langevin, inter- nationally acclaimed for its work in neutron research. Neutron tech- ESRF synchrotron ring at Grenoble. © ESRF niques and synchrotron radiation are in fact quite close to, and complement, one another. Eighteen countries “The European synchrotron will increasingly develop its activities to are involved in this European collaboration. Of the fifty or so synchrotrons meet the exploratory requirements of the nanosciences,” says Bill around the world, only two – one in the United States and one in Japan Stirling, ESRF’s Director-General. “Our objective is to soon be able to – can rival that built in Grenoble. provide beams at the nanometre scale. We are going to convert about a third of the lines to prepare ourselves for what will be the science of the coming decades, while preserving and improving the tool used by 5 500 researchers each year the scientists of today.”

About forty high-performance beamlines are currently in service around the great synchrotron ring of the ESRF, all of which are subject to A multicultural breeding ground continual improvement. Each beamline specialises in one particular technique or field of research. Essentially, synchrotrons are “jacks-of- Because it is used in the most varied of disciplines, the Grenoble all-trades”: machines which permit us to study matter in all its forms – synchrotron brings together physicists, chemists, biologists, physicians solid, liquid or gas. The intensely powerful X-rays emitted by the ESRF and archaeologists – all sharing in new, unpublished experiments, in ring make it possible to observe microscopic or even nanoscopic sam- both basic and applied science, which may very possibly push back the ples of matter, to detect highly diluted and yet still harmful pollutants, or frontiers of knowledge. This multicultural environment encourages a to watch chemical reactions progress by the nanosecond, as if in a film. sharing of ideas and experience, reinforced by the presence of many The European synchrotron, which is operational 24 hours a day, is used trainees, PhD students and postdoctoral researchers. Every autumn, a by 5 500 researchers each year from all over the world and from every day is set aside for young researchers to present their work. There are kind of scientific discipline. Twice a year, projects prepared by about also many seminars and conferences throughout the year. 600 universities and research centres are chosen by committees of The ESRF website is also ideally designed for browsing by members of external experts, solely on the criterion of excellence. The teams of the general public with an interest in science. scientists selected usually work for an average of three days on the line allotted to them. The work done at the ESRF is reported in more than 1 300 publications each year. The world of industry has also long since realised the value of synchrotron radiation and businesses regularly assign research projects to the ESRF in such areas as pharmaceuticals, petrochemicals, microelectronics or even cosmetics. For more information www.esrf.fr ESRF RTD info Special Issue: EIROforum February 2007 23

Researchers from various disciplines working Bending Focusing Undulator magnets magnets on the different beamlines of the ESRF ring. © ESRF

Storage ring Booster © ESRF synchrotron Linac (linear accelerator)

Beamline Seeing the invisible

X-rays are a form of invisible light, only a little of which is size of atoms and molecules. When these are arranged in a regular, even absorbed by the matter it illuminates. They have the capacity manner, i.e. when matter takes the form of crystals, incident X-rays are to penetrate deep into matter to reveal what lies inside. diffracted. It is this technique of diffraction, also known as crystallography, which allows scientists to visualise the atoms at the heart of matter. Since the beginning of the 20th century, X-ray crystallography has thus become an cannot see or understand the world around him without one of the indispensable disciplines of modern science. light. From prehistoric torches to the modern laser, he has Minvented a whole range of light sources to complement the possibilities offered by the natural light of day. New challenges In order to see better from a distance and close-up, and thereby enlarge his field of vision, man has used his ingenuity to create optical instruments In 1947, physicists working on a new type of particle accelerator, the like telescopes and microscopes, but even these highly efficient instruments synchrotron, observed a light issuing from the ring in which the electrons only show us a tiny fragment of reality. Much of the world around us were circulating. The importance of this light, known as synchrotron remains hidden from view if we rely entirely on what is called “visible” radiation, was not immediately appreciated. It was not until the 1970s light – i.e. those forms of electromagnetic radiation perceived by the that scientists realised its extraordinary properties, and decided to human eye. construct machines designed solely to emit synchrotron light in order to study matter at the atomic level. The Grenoble synchrotron, equipped with undulators which cause the The Röntgen legacy electron beams to zigzag, can generate “hard” X-rays: particularly intense, coherent and stable. The intensity of light produced, a thousand Late in the 19th century the German scientist Wilhelm Conrad Röntgen, billion times that of a conventional medical X-ray machine, allows the first Nobel laureate in physics, discovered an extraordinary new scientists to carry out experiments they could not even have imagined means of seeing the world: X-rays. These are a form of invisible light only fifteen years ago. a little of which is absorbed by the matter it illuminates. They have the The techniques used on the beamlines have gradually diversified and capacity to penetrate deep into matter to reveal what lies inside. Apart become more and more sophisticated. The truth is that X-rays interact from their applications in all areas of medicine, they also allow us, for with matter in all sorts of ways, and the intensity of synchrotron radiation example, to check the contents of objects like a suitcase or container has allowed the opening up of hitherto uncharted fields of study. One without the need to open them, and permit scientists to investigate the spectacular example of the advances made possible by the new interior of matter in a non-destructive manner. In an X-ray photograph technology is the possibility of monitoring chemical or biological reactions the rays identify materials of different densities, such as a filling in a within extremely short timeframes. For example, the transformation of tooth for example, by absorption contrast (the filling absorbs more of the gases released in combustion as they pass through the interior of a X-rays than the organic material of the tooth). catalytic converter can be observed. It is also possible to use a special The penetrative power of the X-ray is accompanied by another property, less chamber to reproduce the conditions to which materials are subject at well-known to the layman: the wavelength of X-rays is ten thousand times the very centre of the Earth (a simultaneous combination of very high shorter than that of visible light, to the order of one tenth of a nanometre. pressure and very high temperature), and to obtain essential information This is a crucial characteristic of X-rays: they correspond in scale to the on materials subjected to these extreme conditions. 24 RTD info Special Issue: EIROforum February 2007 ESRF

Over the last few years, thanks to synchrotron radiation, we have witnessed a veritable revolution in molecular and structural biology. At present the seven beamlines of the ESRF dedicated to protein crystallography represent about a quarter of its scientific activity. Biologists are making more and more use of this tool to see, understand and control living Life through matter better. the eye of the synchrotron

Illustration of the three-dimensional protein RecO – a protein involved Illustration of the three-dimensional structure of the protein MTHase – in the repair of genomic DNA following damage caused by irradiation. an enzyme involved in the synthesis of a disaccharide (trehalose). © Joanna Timmins © Joanna Timmins

ow far we have come since the discovery of the DNA double-helix, has the fascinating property of resistance to very powerful doses of made with the assistance of X-rays half a century ago. We have radiation. Its genome has been sequenced and some of its proteins Hnow established the structure of thousands of proteins and, in crystallised. This bacterium has no exceptional characteristics, except its some cases, protein crystallography has become a matter of routine. ability to repair any breaks in DNA double helices, which are generally But scientists are now embarking on more and more difficult ventures, fatal to cells, very effectively. such as the study of membrane proteins or macromolecular complexes. “Since this bacterium can resist levels of radiation not found on Earth, Fortunately, synchrotron radiation, with its remarkable intensity, allows it cannot be an acquired characteristic. This resistance to radiation may research to advance ever further. Among the challenges in the area of be just an indirect consequence of its exceptional efficiency in a whole public health, the fight against viruses and bacteria requires structural range of classic cellular functions – which would also explain, for example, information which is absolutely crucial in producing the medicines, vaccines its remarkable resistance to drought,” says Joanna Timmins. If we had and antibiotics of the future. a better understanding of the fundamental mechanisms involved in repairing breaks in DNA in D. radiodurans, it might help us to see how they occur in radiation-induced cancers, such as skin cancers. Alzheimer’s, malaria, avian flu... In the same group, Laurent Terradot is working in collaboration with the Pasteur Institute on Helicobacter pylori, the bacterium responsible for To see the atomic structure of a protein using X-rays, it is first necessary gastric ulcers. Study of the interactions among the proteins involved in to make a protein crystal. It is only in this crystallised form that proteins will the detoxification of acidity – a process essential to the survival of bacteria reveal their atomic structure under X-ray illumination. With synchrotron in the stomach – has led to the discovery of a unique mechanism. radiation, extremely powerful detection instruments and very advanced “Helicobacter pylori accumulates nickel and then releases it when acidity computer software, highly complex protein architectures can be visualised increases. The released nickel allows another protein in the bacterium and clarified. to trigger the process of detoxification. Last year the same team published Synchrotron crystallography is often an indispensable tool in the success the structure of the 12 proteins which comprise the machinery by which of the most varied research projects. Because of the extremely narrow the bacterium injects its toxins into human cells. These are all proteins focus of certain rays it has been possible, for example, to identify the which could be targeted for therapeutic purposes.” basic structure of the axis of amyloid fibrils, seen in Alzheimer’s, whose atomic structure is very difficult to observe. The structure of the antigen AMA1 of the plasmodium which carries A cure for gliomas? malaria, currently being tested as a vaccine candidate, has also been identified by crystallography at the ESRF, as has the structure of the In the field of radiology, methods developed by teams at Grenoble University hemagglutinin responsible for the virulence of the virus which caused Hospital in association with the ESRF have yielded highly encouraging the great Spanish influenza epidemic of 1918 (in which interest has results. They are based on a synergy between the treatment of tumours with recently been revived by new threats of a global avian flu epidemic), and radiation and a form of chemotherapy based on cisplatine, a prominent that of recBCD, a protein complex which drives the repair of bacterial DNA. antineoplastic used in attempts to treat gliomas – cerebral tumours for which at present there is no cure. “By selecting a specific platinum energy threshold for the radiation therapy, the absorption of cisplatine is multiplied. Radiation resistance and DNA repair Laboratory rats will survive for a few weeks with radiotherapy or chemotherapy alone, a little longer when the two are combined. But with monochromatic Joanna Timmins, a member of the macromolecular crystallography team, synchrotron radiation at the right level, we see genuine remission being is particularly interested in the bacterium Deinococcus radiodurans which achieved – for the first time,” explains Alberto Bravin. ESRF RTD info Special Issue: EIROforum February 2007 25

Schematic representation of the protein NikR of Helicobacter pylori in its tetrameric form (two chains of two colours). • The first image shows the structure obtained without nickel. • The second shows it after nickel (represented by the yellow balls) has been incorporated. The nickel atoms attach themselves to the interface of the two dimers, allowing the protein to be assembled in compact form and the movement of the DNA binding domains to be stimulated. This is an intermediate phase. • The third illustration shows the final phase, in which the nickel is seen to be incorporated in the NikR crystals. The three structures have thus allowed us to obtain successive images of the incorporation of the nickel and to see how its addition triggers structural changes which impact on the exterior DNA binding domains. © Journal of molecular biology Silk: source of bio-inspiration

Studying life is one thing – but copying it is an altogether different proposition. “Nature is an inexhaustible source of inspiration,” says Mary Rose, Stardust, Christian Riekel, director of the Soft condensed matter team at the ESRF. “It was the resistance, elasticity and bio-compatibility of a thread arsenic and iodine of silk which gave us the idea of using it as a replacement for human tendons.” These properties suggest many other uses too, as long as it proves possible to manufacture these fibres industrially. The team is developing imaging techniques and conducting studies to understand better how this polymer of a very simple protein can form a filament in a water solution – just a routine task for the common spider. “Microfluidics, which uses chips containing tiny channels, or other comparable techniques, allows us to visualise at each moment, under the X-rays, how a protein in solution changes its configuration when one adds an aggregate product.” Other researchers are attempting to construct artificial muscles using a copolymer formed of a hard polymer and a soft polymer. “When the ambient acidity changes, this copolymer absorbs water, swells up and triggers a mechanical effect. This occurs on the level of a single fibril, microscopic in scale, but requiring a length of time that seems infinite when compared with the speed of natural muscle.” Analysis of the deterioration of the wreck of the Mary Rose, a ship Silk, tendon or muscle – the interactions of the rigid protein fibres with belonging to Henry VIII of England. Courtesy of the Mary Rose Trust the soft matrix surrounding them plays a major role in their mechanical properties. These fibres are immersed in a matrix to which they are anchored by links which rupture in the presence of water. What was, up In synchrotron-radiation imaging, the rays can illuminate the to that point, a homogenous ensemble, then begins to break up. “How whole sample or scan it point by point with a resolution of are these ruptures at the molecular level integrated and how do they between 100 µm and 100 nm (0.1µm). This allows the transmit themselves to the entire muscle or tendon to change its state? presence and condition of trace elements like metals to be How do these different organisational levels work together? To understand detected in the tiniest quantities. This type of detection is these processes we need to be able to study the same phenomenon at used in a wide variety of research: archaeology, space research, these different levels of organisation. Thanks to the nanometric precision environmental studies, new medical treatments, etc. Teams of provided by the ESRF beamlines we can now introduce techniques scientists come to the ESRF, for example, to understand and which allow us to study this transition from the microscopic to the prevent the formation of the sulphuric compounds which macroscopic much more closely than was possible even ten years ago.” cause the deterioration of the timber in the wreck of the famous Mary Rose, the ship which belonged to Henry VIII of England. They also come to carry out chemical and structural analysis of the material brought back to Earth by NASA’s recent Stardust mission, to study the interactions between bone matter and a titanium prosthetic device, or to monitor the metabolisation of arsenic in a strand of hair. 26 RTD info Special Issue: EIROforum February 2007 ESRF

A formidable tool in biological exploration, the synchrotron Deciphering is also a superb instrument for understanding life forms from the past. the origins of life alaeontologist and primate expert Paul Tafforeau first used the European Synchrotron Radiation Facility (ESRF) X-rays in 2001 to Panalyse the three-dimensional structure of primates’ teeth. The thickness and distribution of the enamel of the teeth are important characteristics in the study of hominoid evolution, but their description requires rigorous and objective methods of measurement. “Tooth enamel is relatively fine in the big African apes of the modern world, and relatively thick in orangutans. It would seem to indicate a thickening over the course of hominoid evolution, even if we still lack precise data with respect to our two most distant ancestors, Toumaï and The Toumaï skull Orrorin tugenensis.” © Mission Paléoanthropologique Until recently the only way of studying this enamel was to actually cut Franco-Tchadienne into the tooth. Such an invasive method was simply not acceptable with rare, or even unique, samples. But for some years now laboratory micro- tomography (using X-rays) has allowed sections of the tooth to be vie- Lower right mandible wed virtually, without destroying the tooth. However, the process was attributed to slow, sometimes imprecise, and the resulting images were often poor in Sahelanthropus tchadensis. contrast. At the ESRF it is possible to obtain images rapidly and of far There has been some superior quality, which substantially increases the possibility of investi- controversy about the third gating very old fossils which have undergone extreme mineralisation. molar, with some scholars claiming it is a left molar re-attached to a right mandible. Apart from Synchrotron and phase contrast certain clear anatomical features indicating that Some fossils have been so radically altered by the process of diagenesis this is definitely a right that in classic absorption imaging they no longer show any contrast. tooth, the 3-D extraction of the crown and root demonstrates In cases like these it is possible to use another technique based on the that the fit is almost perfect and that the tooth is definitely property of partial coherence of the ray produced by certain synchrotrons: in its natural position. © Tafforeau, Brunet the propagation phase contrast. “Phase contrast permits us to see numerous structures in fossils which are totally invisible in classic imaging. The results are striking on fossils such as insects trapped in amber, as Comparisons of the jaws well as teeth. You can obtain 3-D reconstructions which show the of Khoratpithecus enamel-dentine junction very clearly, even if the tooth itself no longer shows chiangmuanensis any absorption contrast owing to diagenesis. These analyses of enamel (12 million years old) distribution provide new features we can use in studying the phylogenic and Khoratpithecus piriyai relations between fossil primates and living primates. The thickness of (7 million years old) both found in Thailand. The the enamel also tells us a lot about the diet of the specimens studied. specimen on the left is a In some cases fine enamel wears out rapidly, leaving a pattern of sharp 3-D composite built up ridges, more suitable for a vegetable diet, while thick enamel may from single teeth of the sometimes indicate a diet of rougher foods, including – for example – male and female scanned nuts or grains.” on the ID19. © Tafforeau, Jaeger, Chaimanee 580-million-year-old embryos

Palaeontology is booming at the ESRF. In 2003 an international study on charophyta (420-million-year-old algae) allowed scientists to see in detail their fructifications and to establish their precise phylogenic position. Some four-cell marine embryos dating from the Precambrian era (580 million years ago) found in phosphates in a site at Doushantuo, in Virtual section of a tiny, China, were the object of intensive international research. 3-D scans 580-million-year-old conducted at the ESRF during a joint Sino-French study project reveal embryo from China. details of the cellular membranes of the embryos, showing clearly that The different colours they divided in asymmetrical fashion to produce cells of different sizes. correspond to the three “We know nothing about their identity or the form of the adult organism, embryonic cells but we do know that such divisions, which still occur in certain marine (blastomeres). bivalves today, create a primitive plan of bilateral symmetry. Today, the Calculating the volume vast majority of living species are bilateralia. Our study, whose findings of each of these shows that the blue cell is larger. were recently published in Science, would therefore suggest that this This observation confirms the interpretation that embryonic feature appeared very early in the evolutionary process.” development involves the formation of polar lobes. © Li, Tafforeau, Chen EMBL RTD info Special Issue: EIROforum February 2007 27

At the cutting-edge of European life sciences

Created in 1974 and now financed by 19 Partner States, the the European Molecular Biology Laboratory (EMBL) is a multi- location research, training and teaching centre. It is based on close collaboration between scientists of all nationalities involved in molecular biology. As well as being a centre of bout 80 research groups are spread throughout the five EMBL excellence in molecular biology laboratories. Its headquarters in Heidelberg (Germany) covers the attracting the best researchers, EMBL also attaches great whole spectrum of research in molecular biology, from the study of A importance to the training molecules to the embryonic development of organisms and the emergence of undergraduate of cellular components. and PhD students. © M.Schupp/EMBL Five laboratories in symbiosis Diffusion, training, debate

The two ‘Outstations’ in Hamburg (Germany) and Grenoble (France) are The diffusion of knowledge and the training of young people called on both on sites possessing synchrotrons. The Grenoble-based ESRF to continue the business of research are two essential parts of the (European Synchrotron Radiation Facility), ILL (Institut Laue – organisation. About 170 PhD students are enrolled in the famous Langevin), EMBL Grenoble Outstation and IBS (Institut de Biologie EMBL International PhD Programme, conducted in partnership with Structurale) founded the Partnership for Structural Biology (PSB) in 24 universities in 17 countries. The research teams offer positions to 2002. The PSB is located in Grenoble on the International Campus of researchers of all nationalities in all stages of their careers. The inter- ESRF, ILL and EMBL, and shares a new dedicated laboratory complex, national conferences and workshops organised each year by EMBL for the Carl-Ivar Brändén Building, with the IVMS (Institut de Virologie the European scientific community are always a great success. Moleculaire et Structurale, funded by Université Joseph Fourier of Also concerned by the societal implications of the incredible evolution of Grenoble). Researchers at Monterotondo, near Rome (EMBL Mouse life sciences, EMBL has given itself the task of strengthening relations bet- Biology Unit), work on the functions of genes. They use their knowledge ween science and society and communicating its research to those to develop mouse models of human diseases to undertake biomedical “outside the boundaries”. The European laboratory proposes a dynamic research, and work closely with the Italian National Research Groups programme (Science and Society) geared towards establishing a dialogue (CNR) and the European Mouse Mutant Archive (EMMA). EMBL's between scientists and the general public. European Bioinformatics Institute, located on the campus of the Sanger In another domain, the European Learning Laboratory for the Life Institute at Hinxton, near Cambridge (UK), manages one of the largest Sciences (ELLS) allows motivated teachers to delve into the heart of the biological data banks in the world. new cutting-edge aspects of a discipline in which the growth and diversity These sites all work in close collaboration, with a flexibility that is charac- of knowledge are ever increasing. teristic of the institution as a whole. Tasks are carried out by independent EMBL also welcomes EIROforum’s Science in School magazine, which research groups according to thematic programmes. The structures aims to demonstrate new methods of teaching sciences (see page 4). encourage interdisciplinary work and interaction between teams. EMBL also offers a wide spectrum of services to European scientists. The most widely used are the free database of the European Bioinformatics Institute (EBI) and access to the cyclotron in Hamburg and the synchrotron in Grenoble. Technology and instruments develo- ped by the organisation are also available to companies in the sector (EMBL-Enterprise Management). For more information www.embl.de 28 RTD info Special Issue: EIROforum February 2007 EMBL

In 1870 the German naturalist Ernst Haeckel published the first genealogical tree, a summary of all the knowledge available at that time about the genealogy of life on earth, The tree of life also known as phylogenesis. In 2006 six researchers, led by the European Molecular Biology Laboratory’s (EMBL) Peer Bork, published a new in the genomic summary of the topic in Science. One hundred and thirty-six years separate these two views, which at first appear to be very different, but which both have a common objective: to piece together the biological evolution of the species pre- era sently living on Earth. They are based on the same basic principle: two species that share a common characteristic have inherited it from the same ancestor.

hat has changed, in almost a century and a half, is primarily the A 36-gene, 191-genome jigsaw nature of what is considered to be a common characteristic. WIn Haeckel’s era, only the morphology of species could be studied. One of the most daunting tasks EMBL had to deal with, therefore, was Interest therefore focused on body plans, skeletons, dentition and the to trace these horizontal gene transfers. Researchers studied anatomy of the organs. For about a century, generations of biologists 191 genomes (1) with a shared heritage of 36 genes. Even in the era of worked to refine and clarify the numerous branches of Haeckel’s tree. bioinformatics, the study could not be fully automated. Patience was The 1970s disrupted this patient research. The discovery that DNA needed for the preliminary – and almost entirely manual – research into holds genetic information and advances in analytical techniques the indices in order to rule out those genes resulting from horizontal allowed research to be based on biochemical rather than morphological gene transfer. At the end of this very tedious task there remained only characteristics: amino acid protein sequences and ribonucleic acid 31 genes, those which researchers were sure were a result of phylogenetic (RNA) base sequences – which constitute the cellular machinery for transmission. protein synthesis – and even deoxyribonucleic acid (DNA) base sequences. Two decades later there has been another upheaval, also triggered by a major innovation in analytical techniques. The automation of genome sequencing, supported by the rapid growth of bioinformatics, makes it possible to compare huge amounts of data. Phylogenetic reconstruction is no longer based on a gene or a protein, but on the entire genome.

Horizontal gene transfer

“In the early stages, this influx of new genomic data provided more confusion than clarification. It posed more new questions than it solved,” points out Peer Bork. Bringing order out of the disorder caused by the abundance of sequencing data was one of his initial goals when he began the work eventually published in Science as the new “tree of life”. This project has the same aim as Haeckel’s work – to reconstruct the genealogy of living things – but with the difference that genomes now replace morphology. There had already been numerous attempts to do this, but they always came up against the problem of horizontal gene transfer, the ability of unicellular organisms – whether they have nuclei, like yeasts or protozoa, or no nuclei, like bacteria – to exchange genes within the same generation. The result is that the fundamental principle of phylogenesis (which consists of assigning a common ancestor to species that share characteristics) cannot be used in this situation. Two species may have the same characteristic because they exchanged it, and not because they inherited it from a common ancestor. Horizontal gene transfer therefore causes systematicians great problems.

Pedigree of Man: in 1870, by reconstructing the classified genealogy of all living things known in his time, Haekel built the first genealogical tree from the roots up, from the reign of the Monera (prokaryotes) to Man at the top. EMBL RTD info Special Issue: EIROforum February 2007 29

According to the principle of the common ancestor, the presence of 31 genes – which researchers are now certain correspond to a phylogenetic transmission within the genomes of 191 species studied – have allowed the EMBL team, led by Peer Bork, to draw up a new genealogical tree, published in Science magazine in 2006.

It was only at the end of this preliminary selection that powerful bio - A new day informatics programs could be implemented to reconstruct the presence of each of these genes in the genomes of the 191 species, and therefore New light has been shed on the very fascinating question of the origins to draw up a new tree of life. of life on Earth, as the tree of life strongly suggests that the first living thing that appeared on earth lived in a very warm environment; one of these warm sources could very likely be the ocean floors heated by The smaller we are, the faster we evolve magma from the earth’s mantle. The tree of life will continue to grow as sequencing data from new “This study, the scope of which has not yet been matched, upsets many genomes is added, in an almost entirely automated manner, and accepted ideas on the relationships between living things,” states the displayed on the dedicated website managed by EMBL. The influx of Irishman Christopher Creevey, a post-doctoral researcher in Peer Bork’s new data might cause an information surge: 352 genomes had been team. “A fundamental lesson can be learned from the study: the smaller processed when the research was published in Science, and no less the genome, the faster it evolves.” In one sense, bacteria are therefore than a thousand are nearing completion. more evolved than mammals… The new tree of life proposes no less than fifteen revisions to our current conception of the genealogy of living things. One of the most important (1) 150 bacterial genomes, 23 eukaryotic genomes – including one for Homo changes is to place vertebrates and insects on the same branch – distinct sapiens – and 18 archaebacteria (very ancient nucleus-bearing bacteria). from that of nematodes – when it had been thought for about ten years that the vertebrate branch should be separate from that of the nematodes and insects. “Since the publication of the results of our work in Science we have For more information been overwhelmed by demands from researchers for more detail, like EMBL tree of life website close-ups, on particular branches of our phylogeny in which they were www.bork.embl.de/tree-of-life specialists,” relates Christopher Creevey. This synthesis was therefore very much anticipated by the scientific community, but was also echoed in the general public. “We even got requests for authorisation to print our tree of life on T-shirts!” Contacts Peer Bork [email protected]

Christopher Creevey [email protected] 30 RTD info Special Issue: EIROforum February 2007 EMBL

Who was Urbilateria?

Urbilateria… Have you ever heard this term? It is the name given to the hypothetical ancestor of all animals that are “bilaterally symmetric” – with respect to the centre of their bodies – from worms, to insects and fish to mammals. Urbilateria lived over 600 million years ago, but almost nothing is known about this creature as it left no fossils. Like particles which have never been observed – but which have been theoretically predicted – and that physicists have followed for years, Urbilateria intrigues evolution specialists. Research carried out at EMBL has made it possible to find out a great deal about this ancestor from so long ago.

he famous Urbilateria actually gave rise to two vast groups marked by bodily symmetry. Phylogeneticists identify two separate categories: Tthe deuterostomes – including, among others, fish and mammals – and the protostomes. The latter group is further divided into two: the ecdysozoans, such as nematodes, insects, spiders and crustaceans, and the lophotrochozoans, such as molluscs and worms. Researchers Detlev Arendt, Peer Bork and Florian Raible revisit the fable of the “The Tortoise, the Hare… and the Worm”, comparing the relationships Armed with this information, an international team led by Detlev between species, depending on whether they clear the stages of evolution Arendt's group at EMBL started a huge study comparing the DNA of the quickly – or very slowly like Platynereis. © M. Schupp/EMBL three main lines descended from Urbilateria. Though fully sequenced insect, fish and mammalian genomes are available, researchers are nevertheless faced with the complete absence of any genetic sequences representing the lophotrochozoans.

The advances brought about by the study of Platynereis History (picture) do not stop there. They also helped to throw light on a puzzle that has caused biologists headaches of the eye for a long time: the appearance of the eye.

arwin already knew that it was highly improbable that a structure as complex as the eye should appear abruptly, by Drandom variation followed by selection, as predicted by the theory of evolution. In the late 1980s, work done by Walter Gehring, in Basel, resulted in the first evidence showing that a single gene, switching on a cascade of some 2500 others, was enough to bring about the evolution of the eye, and that this gene was identical in mice, fruit flies and squid. These results suggest that the eyes of mammals, insects and cephalopods, even though they are all so different, each come from the same rudimentary eye, created by a single gene. © EMBL The first appearance of this primitive eye during the evolutionary process should therefore be looked for in an ancestor common cells, namely the ‘rhabdomeric’, found in invertebrates, and the to each of the three branches, namely the famous Urbilateria. ‘ciliary’, characteristic of vertebrates,” explains Detlev Arendt. The task of describing this mysterious proto-eye was still to be When I first saw electron microscope slides of the ciliary photo- achieved, however. Once again, the answer came from receptive cells of Platynereis I was struck by their similarity to the Platynereis. “This lophotrochozoan has two types of photoreceptor cones and rods found in the human retina.” EMBL RTD info Special Issue: EIROforum February 2007 31

A small but useful worm The second result was even more astonishing: more than half of human introns were preserved, sometimes as close as a nucleotide, in the They finally opted to use a small marine worm known as Platynereis Platynereis, while the proportion for insects is only about a quarter. After dumerilii as their study model. What are its advantages? Easy to grow in the studying the phylogenesis, we can conclude that more than two-thirds lab, Platynereis is a living fossil. The organisation of its body in repetitive of human introns must have been present in Urbilateria. segments seems to have barely evolved in 600 million years. Its phylo- However, these sequences could not have been created twice. This genetic identity implies that all complex characteristics found in the extraordinary preservation suggests that introns, far from being “junk lophotrochozoan Platynereis and for example, in the deuterostome DNA”, play a very important functional role, even though this fact is still Homo sapiens should already have been present in Urbilateria. under debate. Is this a unique characteristic of introns? Not at all, as A partial sequencing of the Platynereis genome was therefore carried shown in the third result published in Science: analysis of the sequence out to fill this void. It identified 30 genes also present in the two other of 442 proteins present in all three branches shows that Platynereis is main groups. Rather than focus on the sequences that encode these closer to Homo sapiens than to insects. genes, the analysis focused on the non-coding sequences that divide Therefore, counter-intuitively, our own species is genetically much closer them up. These sequences make up what are called introns (as opposed to Platynereis than to organisms that are as sophisticated as, for example, to the sequences known as exons, which encode the protein sequence). the bee. Detlev Arendt pushes the logic even further: “Our results can The role of the introns is still a hot topic for debate. Some believe that be interpreted by saying that Homo sapiens has kept certain ancestral they are evolutionary holdovers in accordance with the “junk DNA” characteristics…” A paradox? Not really. It would seem as though the theory; others see a tricky biomolecular structure that makes it possible ecdysozoan branch, to which insects are linked, favoured an evolutionary to produce numerous proteins from a single gene (by linking different pattern using a simplified form of genomes and a reduction of their intron exons). The phylogenetic comparison of introns might therefore help count, while the two other branches kept the significant fragmentation solve part of the puzzle. that was already present in Urbilateria. “Ecdysozoans, therefore, evolved quickly,” continues Detlev Arendt. “They distanced themselves further from their common ancestor than the lophotrochozoans and deuteros- Platynereis and Homo sapiens tomes, which followed a more conservative evolutionary pattern.”

This study, published in November 2005 in Science, provided a surprising preliminary result: Platynereis contains in average 7.8 introns per gene, which is fairly close to that of man (8.4), but many more than insects and nematodes, which contain between 2.4 and 5.4. This indicates, by For more information Contact virtue of the common ancestor principle, that Urbilateria also had to www-db.embl.de/jss/EmblGroupsOrg/g_172.html Detlev Arendt have a genome that was high in introns. [email protected]

Proof of this intuition was still to be found, a task that was achieved “Let's imagine a photoreceptive cell present in one of using the molecular imprint that was active at the cellular level like Urbilateria’s ancestors,” he begins, getting out a notepad, “and a fingerprint. The ciliary photoreceptive cells were transferred not let's also imagine that the duplication of a gene that encodes for only to this worm but to all vertebrate lines, with a common a photoreceptor gives rise to two types of cells, each inheriting a signature. The logical conclusion is that although it was almost version of the gene: one of them is specialised in the reception of certainly not capable of actual vision, Urbilateria already had this light information and the other in processing it. Cells are often cellular type, adapted for photoperiodism, used to adjust the displaced during embryonic development. Let's then assume that reproductive cycle to the alternating rhythms of day and night. one of our cells migrates, while staying connected to its ‘sister’ Armed with these discoveries, Arendt hopes to slowly reconstruct by a string of cytoplasm. We get a true proto-nervous system with Urbilateria’s central nervous system. “I am fascinated by the fact the string of cytoplasm acting as the axon!” that we find exactly the same hormones and neurotransmitters in In the researcher’s notepad, there is a diagram of a neural network, Platynereis and in man, while some are absent in insects. This as it could have been laid out in Urbilateria. Generations of biologists again shows that the latter branch evolved faster.” Because the could only imagine this distant ancestor. Thanks to new molecular molecular imprint helps to reconstruct the genealogy of cellular biology techniques, it is taking shape before our eyes. types in the same way that the phylogenetic tree is reconstructed, researchers can already construct models of the appearance of the nervous system. 32 RTD info Special Issue: EIROforum February 2007 EMBL

In the beginning, there was shape

Eric Karsenti is the head of the cell biology and biophysics unit at EMBL. In 2009, 150 years after Darwin’s publication of The Origin of Species, this cytoskeleton specialist plans Illustration of microtubular strands to set out on a sailing vessel to re-enact the voyage of the HMS of the cytoskeleton of yeast (green), Beagle during which Darwin made numerous observations combined with the mitochondria (yellow) which later supported his theory of evolution. and the cell nucleus (purple). © EMBL

What is the relationship between your research at the EMBL on the done on evolutionary biology at the cellular level. There could be fascinating physio chemical mechanisms that occur in the cellular skeleton and your studies done on the cytoskeleton of unicellular eukaryotes, particularly interest in evolution-related issues? plankton, some of which are veritable treasure troves in living fossils. The issue that always fascinated me was the complexity and diversity of shapes that life can take. How is such diversity possible, and how could Are there any examples where the mutation of a gene encoded as a cytos- it have been produced through evolution? This is an age old question, keleton protein causes the creation of a new structure? as old as Aristotle. Though neglected these days, this question was very Certainly. That’s what happens in the mutation of dyneine for example. popular during the nineteenth century and at the beginning of the twentieth. This protein of the cytoskeleton functions like a small engine that moves Thus the now famous example of the Galapagos finches. During the along the microtubules and causes nothing less than an inversion in the voyage of the HMS Beagle, Darwin described 13 species of finch that lived placement of the organs: the heart to the right, the liver to the left, etc. on the Pacific archipelago, which differed from each other in the shape I am not claiming that all new structures come about as a result of of their beaks. This became a paradigm which we now call speciation: mutations of cytoskeleton genes, though. In the case of Darwin’s how can the shape of the beaks of finches vary through evolution, and finches, we now know that the formation of the beak is linked to a variation how could it happen so fast? in the level of expression of a gene that encodes a hormone regulating the The answer is found by going down a level in the organisation of living proliferation of cells. things, that is, by moving from the organ level to the cellular level. The I think, however, that the study of the physiochemical and dynamic cytoskeleton is what gives the cell its shape. Therefore in order to principles underlying cellular morphogenesis is essential in understanding understand morphogenesis, I started to work with a team comprised of both how evolution could have led to the splendour and diversity of the living biologists and physicists on the cytoskeleton and its main components: things we are lucky enough to deal with today. actin, tubulin, and the proteins related to them.

Can you place a date, in evolutionary terms, on the appearance of the cytoskeleton? All eukaryotic (nucleus-bearing) cells have one. Prokaryotes (cells with no nucleus, like bacteria) have no such structure, despite the fact that some similar proteins are present. There must, therefore, have been a moment in evolution when genetic material became so complex that the distribution of chromosomes into two identical groups required a more For more information sophisticated structure: the cytoskeleton. In fact, in all eukaryotes, www-db.embl.de/jss/EmblGroupsOrg/g_40.html chromosomes are distributed by a mitotic spindle made up of micro- tubules. This poses an interesting problem, the possible co-evolution, during the appearance of the eukaryotes, of a great number of genes involved in controlling the division and shape of the cell. Unfortunately, Contact this is a little-studied issue and it is unfortunate that more research is not Eric Karsenti [email protected] ESA RTD info Special Issue: EIROforum February 2007 33

European space without frontiers

The European Space Agency has been a leading force in the fields of science and technology, and planning and implementing Europe’s presence in space, since 1973. The Agency is a collaborative organisation supported by a number of different Member States within the European Union (1), along with Switzerland and Canada.

SA is engaged in the whole spectrum of activities in space. It manages New cultural frontiers the construction of Ariane rockets and their launching from the EKourou base in French Guiana, the design and development of The great adventure of space exploration plays a satellites and their equipment, as well as the preparation and imple- decisive role in the future of humanity. There is mentation of manned space flights. At the same time, it develops and enormous public enthusiasm for all things to do implements large-scale scientific programmes and international projects with space, particularly among the young. Aware – particularly those involving European participation in the International of the interest its activities hold for the general Space Station (ISS). public, ESA does much to help promote scientific As Europe’s main scientific and technological tool for the implementation culture and education. Its well-designed website of an independent European space programme, ESA has built close provides clear, lively, well-documented information links with the European Union. It operates in a broad range of fields: and striking photographs. One of its most attractive communications, navigation, environmental monitoring, development of features is the ESA kids page (available in several new space technologies – in particular for the major Galileo and GMES languages), which is a magazine for young people, (Global Monitoring for Environment and Security services) projects. combining education and entertainment. ESA has also set up an educational Foundation (the International Space Station Education Fund Paris, Noordwijk, Darmstadt, Frascati, Kourou – ISSEF) which distributes teaching materials for various educational levels (from primary school Employing around 1 900 people, ESA is a remarkable example of the to university). operational implementation of a Europe without frontiers. Based in Paris, its political and executive headquarters coordinates close cooperation between the Agency and all the space centres of its national and global (1) The 17 members of the Agency are as follows: partners, managing the whole range of its scientific programmes. The Austria, Belgium, Denmark, Finland, France, European Space Research and Technology Centre (ESRTC) in Germany, Greece, Ireland, Italy, Luxembourg, the Noordwijk (NL) is the focus for R&D activities, where most of the Netherlands, Norway, Portugal, Spain, Sweden, probes and new technologies to be sent into space are prepared and Switzerland and the United Kingdom. Canada is tested. In Germany the European Space Operations Centre (ESOC) involved in certain projects on the basis of a at Darmstadt is the control centre for European satellites in orbit, cooperation agreement. Hungary, the Czech while at Cologne the European Astronauts Centre ( EAC) prepares Republic and Romania enjoy the status of the permanent team of European astronauts for their missions. European Cooperating States. Finally, the ESA Centre for Earth Observation (ESRIN), located in Frascati (IT), collates, organises and distributes the data sent back by observation satellites and serves as the Agency’s main information centre. And we should not forget the Ariane launch pad at Kourou in French Guiana, of course.

> www.esa.int > www.esa.int/esaHS/education.html

Launching of the Giove-A satellite © ESA 34 RTD info Special Issue: EIROforum February 2007 ESA

David Southwood, Director of Science at ESA: “Observation from space is now permanently used to understand the way the Earth’s ecosystem and its sub-systems function. It reveals a number of essential phenomena which it would be impossible The revolutions to see in any other way.” © ESA of offshore science For David Southwood, Director of Science at the European Space Agency (ESA), there are two main kinds of space science. One looks outwards, from our own solar system to the edges of the universe. The other focuses on Earth. Both are related to a threefold question concerning the existence of life: why, how and where?

Space science is an area of research which involves the expenditure of Egyptian hieroglyphics. It is our ambition to decipher the codes governing sums that appear quite staggering. Is Europe right to devote so much the evolution of matter in the solar system – the matter from which life energy and so many resources to it? itself was born. Let’s be realistic. Europe hasn’t gone into space primarily to do science. The ability to put satellites in orbit is now an essential strategic and But space does not stop at the edge of the solar system… economic tool in telecommunications, navigation, security, etc. It’s a Far from it. Beyond the solar system there is the enormous field of major issue of independence. A few centuries ago a modern nation had observation opened up to astronomers and astrophysicists by tele- to have a fleet and be able to send its ships from one continent to another. scopes and detection equipment mounted on satellites orbiting the In the same way, we have to be able to send our spacecraft wherever Earth. The vast array of images of the stars sent back by the Hubble we want. ‘observatory’ is well known, but there are other, less well known instru- But once we have this capacity, we can also use it for scientific purposes. ments, such as XMM-Newton, a craft dedicated to picking up X-rays, To abstain from such activity would be absurd, at a time when advances which have gathered vast amounts of data of enormous value to scientists. made in our fundamental and practical understanding thanks to space ESA is currently engaged in preparations for a number of projects which exploration are playing a decisive role in so many different fields. Europe will continue the fascinating exploration of space. In two years we will is now a major player in global research; it has vast human scientific be launching – on the same rocket – the Planck and Herschell probes. potential. It has a role to play in scientific research, a realm where we The first will study, in some of the most remote galaxies, the formation must be capable of travelling “wherever we want”. of the Universe in its earliest stages, as its structure first took shape – in other words, the period closest to the Big Bang. The second will analyse What are the scientific objectives of ESA? the organisation of matter in large masses, the formation of the galaxies, Space travel allows us to enjoy two distinct scientific perspectives. One stars and planets. Herschell will be an instrument that casts light on the looks outward and is interested in understanding the universe in which mysterious dark side of the Universe, where gravity transforms mass into we exist and from which we have originated. The other looks downwards, heat as certain stars collapse in on themselves. Next it will be the turn observing this object called Earth, to which we owe our existence. of the Gaia mission, which is designed to delve deep into the heart of In that first outward-looking perspective the key area of interest is, of the intricate cosmic mechanisms of our own galaxy, its billion stars, its course, the exploration of our own ‘neighbourhood’, our solar system, dark matter, etc. more and more of which is now within the reach of our spacecraft. ESA currently has an Express probe in orbit around Venus and another around Don’t these projects tend to make you neglect the observation of the Earth? Mars. The joint Cassini-Huygens mission of 2004-2005 is a success: the Not at all. The Living Planet programme, which brings together all the NASA craft is in orbit around one of Saturn’s moons, Titan, on which the various means we use to observe the Earth, represents about half of all European probe Huygens landed without a hitch. And of course we ESA's efforts in scientific research over the next few years. Observation shouldn’t overlook Smart 1, a satellite which has been examining the from space is now permanently used to understand the way the Earth’s surface of our own moon since 2004, hoping to establish whether water ecosystem and its sub-systems function. It reveals a number of essential was ever present there. phenomena which would be impossible to see in any other way. Over At the same time Europe has made an important contribution to the the last three decades, Europe has been amassing irreplaceable expertise “search for comets”, initiated 20 years ago with the visit of the Giotto probe and knowledge through its deployment of more and more meteorological to Halley’s Comet, an important first for the European space programme. satellites, through the dispatch into orbit of the ERS (European Remote The comets were formed before the planets and may be the primal matter Sensing) 1 and 2 satellites and above all through Envisat, which is the from which the planets were created. Of course, this matter has been jewel in the crown of all our means of terrestrial observation. It is a satellite heated, subjected to collisions, combined with other matter – we need platform from which no fewer than ten instruments have been scrutinising to understand these processes if we are to recover the original “building the oceans, the icecaps, the continents and the atmosphere since 2002. blocks”. This is the great ambition being pursued at present by the Living Planet is the roadmap laid down by ESA in order to fulfil its Rosetta probe, launched in 2004 and scheduled to touch down on the mission in the now vital context of climate change and global warming. comet Churyumov-Gerasimenko in 2014. The probe takes its name A series of six satellites, the Earth Explorers, are on the drawing board or from the Rosetta Stone, which allowed Champollion to decipher already under construction and will be launched between now and 2012. ESA RTD info Special Issue: EIROforum February 2007 35

The Spainsat satellite in place on top of the Ariane 5 rocket. © ESA/S.Corvaja

The north-east coast of Sri Lanka as seen by Envisat after the tsunami of 28 December 2004 (above) and the damage caused by this catastrophe as recorded by ERS-2. © ESA

Each of them will have its own set of tasks to perform, carefully adapted What science tries to understand is how all this – the universe, life on to meet the needs of the ‘doctors’ of the Earth, promoting better under- Earth, perhaps life on other planets – first appeared. If the universe were standing of the great sea currents, ocean salinity, the water cycle, to be born again there is no certainty that human life would emerge atmospheric circulation, the melting of the icecaps, etc. All this will again on a planet no more important than any other, in a galaxy itself proceed independently of the development of meteorological satellites, surrounded by other galaxies stretching to infinity in all directions. as well as the satellites which will form part of the much-publicised Science also has some idea of how the whole story of the universe will GMES system (Global Monitoring for Environment and Security). unfold in the future. One day, five billion years from now, the sun will have become a red giant and will have swallowed the Earth. Perhaps our When you open the ESA website the first link you see is an appealing one planet is the only life-containing region in our own particular universe. for the visitor: it’s called Life in Space. Is it not this underlying question Or perhaps this same universe is literally crawling with life …There’s a of whether there is “life on other planets” which makes space so moral significance to this. In a certain way, if we are indeed unique, then compellingly fascinating to mankind? our survival is of particular importance. But if, on the other hand, we are Well, we already know that there is “life on Earth”... When we observe just one example of life among thousands of others, then it is less the Earth from a spacecraft aren’t we already in fact observing “life in important. When the time comes we would be able to let the lights go space”? And it’s high time we did so too. We know that global warming out in peace… and climate change are processes which will challenge the relations between life and our planet, processes which raise the whole question of Man’s responsibility towards ‘his’ planet. And this relationship also determines the way we look outwards into space. The possibility that our own Earth might one day become uninhabitable is a powerful inducement to studying how the massive greenhouse effect For more information prevents any life forms on Venus and to ascertaining whether, despite its www.esa.int/esaSC/index.html inhospitable appearance, Mars might not harbour some form of primitive life. On Titan, hydrogen, methane, nitrogen and water have been detected... Now if that water were to release its oxygen all the conditions might be in place for life to evolve. What’s more, the possibility of Contact studying other planets outside our own solar system is now opening up – David Southwood a prospect which would have been dismissed as science fiction just c/o [email protected] twenty years ago. 36 RTD info Special Issue: EIROforum February 2007 ESA

The sentinels of the “Earth System”

Space technology has a key role to play in reacting to Medical imaging of the planet changes in the planet’s environmental conditions, many of them causing considerable anxiety, whether it be by esta- From this point of view satellites are real Earth observatories. Any number blishing a diagnosis, developing a treatment or monitoring of examples of their use might be cited. Thanks to remarkably precise space altimeters, the continuing rise in sea levels resulting from global the correct implementation of this treatment. warming can now be recorded independently of the tectonic movements of the continents, which can distort the conventional measurements “ efore my first space flight I was aware, on a scientific level, of how made by tide gauges. Any speeding up of the rise in levels can now be small and vulnerable our planet is. But the emotion which overcame detected rapidly. One of the pioneers of these altimeters, Carl Wunsh, Bme when I saw it from space, in all its beauty and fragility, the emphasises that “these devices have revealed that the oceanic system is cradle of life, made me realise that the most urgent task facing humanity undergoing profound change each and every day, which has transformed is to care for it and preserve it, at all costs, for future generations.” our way of looking at it. We used to regard it as a very slow geophysical Written thirty years ago, these words by the first German astronaut phenomenon, but it has turned out to be a much more complex system Sigmund Jähn might seem a little hyperbolic – if dozens of astronauts in which fluids are being permanently displaced in all directions.” of all nationalities had not since then expressed the same sentiments. At the same time the evolution of the world’s icecaps is also being care- fully observed. Images taken by the ERS satellites show, year after year, the melting process of the Greenland icecap – and researchers can clo- The anthropocene era sely monitor its correlation with changes in sea levels. Another example: Envisat images acquired in August 2006 have revealed the unexpected Is it necessary to seek any further for an explanation of the zeal with presence in the permanent Arctic ice floe of a colossal fault running up which ESA has been planning, for years, to place more and more important as far as the North Pole. “Such a phenomenon had never been observed and sophisticated satellite tools at the service of a planetary conception of before,” says Mark Drinkwater of ESA’s Oceans/Ice team. “This fissure in sustainable development? The coordinated programme that the Space the ice could in theory allow a boat to be sailed from Spitzbergen or Agency has been developing since 2004, Living Planet, is intended Siberia to the North Pole.” essentially to “play a central role in the development of a global capacity to understand planet Earth, to predict the changes affecting it, and to limit the adverse Monitoring the human impact impact of global change on its population”. There is more to global change than just the Furthermore, almost no effect of the wide global warming. Above and beyond the spectrum of human activities escapes the impact on the atmosphere, the changes caused all-encompassing eye of the satellite. to the entire planet by Man in just the last Deforestation, urbanisation (especially of the 150 years are on such a scale that the Nobel- world’s coastlines), disruptions of water winning chemist Paul Crutzen invented the systems by the digging of canals, the drying new term anthropocene to describe the era up of humid zones, the construction of dams, we are living in. The word emphasises the all are methodically recorded by the sentinels extent to which “the age of man” is responsible of the Earth as they revolve in their unceasing for innumerable planetary processes, from orbit. Fires, for example, ever more frequent the evolution of species to the carbon, nitrogen occurrences on the global scale, are now and water cycles. The Global Ozone Monitoring Experiment-2 recorded in the World Fire Atlas, in which new Moreover – and this is what justifies the notion (GOME-2), one of the new-generation instruments data are entered as soon as they are collected. of an Earth System, which appeared at the end which will make an important contribution to “This continuous stream of new data is a of the last century – the evolution of the planet research into the atmosphere, particularly totally innovative resource for researchers,” can only be understood if one combines the by allowing us to collect data on ozone says Mark Fitzpatrick, a specialist in ecology study of the various massive systems of which concentrations. © ESA and evolutionary biology. “It will allow ecologists it is comprised and which are in constant to re-examine old unresolved questions on the interaction: the biosphere (all living things), the cryosphere (the glacial way in which the natural environment reorganises itself after a fire and regions), the oceans, the continental surfaces and, of course, the draw conclusions about how best we should go about regenerating the atmosphere. To understand the dynamics of these different entities, and natural landscape after these events.” Many of our emissions (e.g. above all the results of their interaction, the first stage has to be to methane, nitrogen oxides) are also visible from space, as are the effects understand their behaviour and how they relate to each other. The second of certain ecological catastrophes (such as oil slicks) and natural disasters is to learn how to predict their combined evolution through models. (tsunamis, volcanic eruptions, etc.). ESA RTD info Special Issue: EIROforum February 2007 37

Images taken by satellites have allowed Earth System science to make Greenland as seen by Meris (the Medium Resolution Imaging progress comparable to that made by medicine using all its contemporary Spectrometer). The ice can be distinguished from the clouds, imaging techniques – MRI, scanners, radiography, ultrasound, etc. at the bottom of the image. © ESA Here, shots of Suriname and French Guiana “seen from above”. © ESA

Deciphering using models

Establishing findings is only the first stage in reaching a real understanding Earth Explorers of phenomena. In order to decipher the forces behind them and the relations between them we must make use of models, which must The Living Planet programme has already selected and sche- incorporate as accurately as possible the data and knowledge at our duled six missions between now and 2012 under the general disposal. Undergoing a constant process of refinement, calibration and title Earth Explorers. Whereas formerly the agency favoured testing against the data from satellites ‘assimilated’ by ever more powerful the use of large, impressive craft packed with instruments, the computers, these models are in a way an attempt to reconstruct the Earth current strategy is to respond to the most urgent questions rai- System – an attempt which is continually being renewed and improved. sed by the scientific community using much smaller and more Eventually it will even be possible to create models incorporating the precisely targeted instruments. reactions – or passivity – of human communities in the face of environ- mental change (drought, flood, hotter or colder seasons, rising sea • GOCE (Gravity Field and Steady State Ocean Circulation levels, etc.), because these reactions will assume more and more Explorer) – To be launched in 2007. Centred on the gravita - importance in the way the system functions. This would be no mean feat. tional field of the planet, GOCE will provide information on If, as we must hope, the international community does finally take the movement of the oceans and also on the physics of the measures to protect the Earth System from the destabilisation which Earth’s interior. threatens it, then this will involve new missions for ESA. It will be vital to monitor compliance with the necessary international agreements. Who • SMOS (Soil Moisture and Ocean Salinity) – To be launched in can say, finally, if the key role of the agency is not, alongside its other 2007. The satellite will map soil moisture and ocean salinity, work, to supply humanity with enough images of the planet – both of its improving our understanding of the water cycle. beauty and its wounds – to ensure that its inhabitants eventually appreciate, like the astronauts, that it is their most precious shared possession. • ADM-Aeolus (Atmospheric Dynamics Mission) – To be launched in 2008. It will measure the behaviour of atmospheric winds.

• CryoSat-2 – To be launched in 2009 (as a replacement for CryoSat 1, lost in 2005). Its mission will be to study the thickness of marine and terrestrial ice and their variations.

• Swarm – To be launched in 2010. This will be a group of three satellites studying the dynamics of the magnetic field. The objective: a better understanding of the Earth’s interior and of its climate.

• EarthCARE (Earth Clouds Aerosols and Radiation Explorer) For more information – To be launched in 2012. It will study the Earth’s radiation www.esa.int/esaEO/index.html balance (Euro-Japanese project).

A number of other projects are currently being studied to follow the missions described above. 38 RTD info Special Issue: EIROforum February 2007 ESA

Europe is currently visiting the two planets closest to Earth Infernal Venus in our solar system – neighbours which may open up new scientific perspectives on the formation and destiny of the If Mars is a frozen world with a rarefied atmosphere, the fascination of planets, and the life or absence of life to be found upon Venus lies, by contrast, in the infernal conditions prevailing on its surface: them. an atmospheric pressure 90 times greater than that on Earth, an average temperature of 465 °C, and a toxic atmosphere made up almost entirely of carbon dioxide, so thick that the sun would remain permanently invisible n a clear sky they can both be seen with the naked eye: Mars, to an observer on its rocky and arid surface. recognisable by its reddish light and Venus, which shines so brightly The ESA satellite has sent back magnificent shots of the gigantic Iin the evening or morning sky. Copernicus, Kepler, Galileo and many atmospheric double vortex which has been discovered above the South other astronomers have studied these sisters of Earth – but only from a Pole, whose sheer force initially baffled astronomers (it was the site of great distance. Today, twin European satellites, Mars Express and Venus an enormous hurricane observed in November 2006). The vertical Express, both positively bristling with scientific instruments, are in orbit stratification of the atmosphere also held a number of surprises, including around the two planets. The first was launched in 2003, the second in strange altitude haloes, opaque up to 90 km and less dense up to 105 km. 2006. Already they have yielded an impressive amount of data. “Similar phenomena can sometimes be seen on Earth, at about 20 km above the surface. They are made up of thin droplets of sulphuric acid originating from volcanic activity,” says Jean-Louis Bertaux, of the French CNRS, in charge of the SpicaV-SOIR instrument. Scientists are therefore wondering if volcanic activity on Venus might not lie at the root of these strange structures. Our neighbours These conditions are all the more fascinating in that early in their history Venus and the Earth were probably much alike (in diameter, mass, comparable chemical composition). These voyages to planets which have ended up close to Earth and yet are so very different illustrate the Mars and Venus emergence of a new scientific discipline: planetary evolution.

For more information Venus Express http://sci.esa.int/science-e/www/area/index.cfm?fareaid=64 Mars Express http://www.esa.int/SPECIALS/Mars_Express/

The double vortex at Venus’ Mars Express beginning its orbit around South Pole. © ESA Mars (artist’s impression). © ESA The star which interests us most Rewriting history

In the summer of 2006, for example, Mars Express observed for the first The spatial body which receives time clouds forming in the atmosphere of the planet, at an unprecedented most attention from the ESA scien- height – between 80 and 100 km! The temperature here is -193 °C. At this tists is, of course, the sun, the star degree of cold, carbon dioxide condenses, which leads researchers to without which the Earth System think that these are gas clouds, probably mixed with dust particles. would not be what it is. The Soho But what really fascinates Mars experts is the question of water. satellite, launched in 1995 and According to Gerhard Neukum of the Free University of Berlin, the data still operational, is a joint project currently being gathered by the range of instruments listening in on the between ESA and NASA which has planet are allowing us to “rewrite its history”. It seems finally to be clear sent back some of the finest close-up that if there was a warm, humid period it did not last more than a few pictures of the sun. Its successors hundred million years and ended no later than 4 billion years ago. include the Cluster group of four However, there are still vast quantities of water on Mars in the form of ice satellites, launched in 2000, and (detected thanks to the Marsis radar instrument), as well as relatively recent Double Star, two probes with © ESA geological structures formed by erosion. But for the German researcher the European instruments sent into orbit on Chinese rockets in recent traces of water in liquid form are connected to volcanic activity, 2003. Although primarily scientific in purpose, these satellite suggesting brief gushes of water which quickly evaporated. observations of the sun are also prompted by more down-to- earth concerns. The ‘choleric’ temperament of our sun, with its solar winds, coronary flares, etc., can cause serious damage to electrical and telecommunications systems on Earth, and to satellites. ESA's next major solar mission is scheduled for the next decade. ESO RTD info Special Issue: EIROforum February 2007 39

The fascination of the cosmos The Tarantula Nebula, situated in the Large Magellanic Cloud, taken by the VLT. © ESO

Even though the largest intergovernmental organisation (1) a veritable forest of mobile dish antennae, each one 12 m in diameter, in the realm of astronomy and astrophysics is European, its which will ‘view’ the heavens using frequencies ranging from 30 GHz to telescopes survey the stars from the mountains of the 950 GHz. The computing capacity used to collate and process all the observation data will be capable of conducting 16 million billion operations Atacama desert in Chile, a region where the lack of humidity per second (1.6x1016). ALMA will allow astronomers to investigate the birth in the atmosphere allows the skies to be observed with a and demise of stars and planets, and to study the most distant of galaxies. clarity recognised as the best on the planet. Established in 1962, ESO (the European Organisation for Astronomical The organisation’s next project, the European Extremely Large Research in the Southern Hemisphere) was the driving Telescope (E-ELT) – a telescope with a diameter of around 30-60 m – has been the subject of intense preparations within ESO for some years force behind the construction of two astronomical observation now. This new telescope is expected to be operational some time in the platforms at an altitude of almost 2 500 m: La Silla (opened next decade. in 1969) and Paranal (operational since 1998). An inexhaustible source of images esigned and constructed by ESO, the observation and detection equipment installed at these two sites is absolutely unique. The most The activities at ESO generate a constant flow of sensational astronomi- Drecent jewel in ESO’s crown is composed of the four elements of the cal images. The organisation’s website regularly features accounts of famous Very Large Telescope (VLT), installed at Paranal. Thanks to new discoveries and pictures of stunning cosmic ‘landscapes’. a large number of instruments and the use of innovative procedures like Astronomy has an immense capacity to amaze and fascinate – a fascination adaptive optics and optical interferometry, and its unique operating method, which should be shared. It reveals the original matrix from which our the VLT allows astronomers to carry out observations of incomparably high solar system, ‘our’ Earth and our life burst forth. ESO therefore tries to quality. be as open as possible with the public, keeping the press informed of The headquarters of the scientific organisation are at Garching, near all developments, holding open days, and running original competitions Munich in Germany. It employs a total of 570 individuals in Europe and for young people throughout the world. Its educational services also South America. Every year more than 1 700 requests for observation time produce superb teaching materials and run special training courses for come into ESO from Europe and beyond. In 2005, more than 600 ground- teachers each year. breaking studies carried out using the facilities at the Chilean observa- tories were published in scholarly journals. (1) ESO has twelve member countries: Belgium, Denmark, Finland, France, Germany, Italy, Netherlands, Portugal, Spain, Sweden, Switzerland and UK. Science that looks to the future

Astronomy and astrophysics are sciences which continually look towards the future. Since 2003, construction has been ongoing at the new Llano de Chajnantor site in Chile, at an altitude of 5 000 m, which will be home to the largest array of telescopes ever built. The project, known as the Atacama Large Millimeter Array (ALMA), is the fruit of For more information collaboration between the member countries of ESO, the United States, www.eso.org Canada, Japan, Taiwan and Chile. This platform will be equipped with 40 RTD info Special Issue: EIROforum February 2007 ESO

Aerial view of the summit of Paranal, showing the four elements of the VLT, the world’s largest telescope. In the foreground the Yepun telescope; from left to right Antu, Kueyen and The black hole saga Melipal. © ESO

Black holes were originally no more than the mental inventions its gravitational energy is released in the form of intense heat and radiation of theoretical physicists. Now, however, astronomers can – first in the form of radio waves, then infrared, then light, UV and X-rays. actually identify and observe them. They offer a wealth of The black hole which has exercised the most powerful fascination for astronomers is located at the centre of our own galaxy, the Milky Way. information on the nature and evolution of galaxies. The For a long time astronomers had wondered about an enigmatic and very latest discoveries in this field have been among the great powerful source of radio emissions called Sagittarius A and regarded as success stories of European astronomy. a candidate for the title of the “supermassive centre of our galaxy”, but had not been certain whether it was in fact a black hole.

he thrilling story of black holes began back in 1963, with the first identification of quasars – very distant objects emitting a pheno- 2.7 million times the mass of the sun Tmenal amount of energy. The brightest ever recorded, 3C273, located in the constellation of Virgo, is a billion billion times brighter than Precise, irrefutable and definitive proof was eventually found by an inter- the sun. Only gamma-ray bursts produce more energy than quasars national team at the controls of one of ESO’s four VLT telescopes in (see p. 42). Chile, using its adaptive optics system (see box). After ten years of observation (1992-2002), the researchers finally obtained striking images of the star S2. This star, with a mass fifteen times that of our own An all-consuming attraction sun, orbits the famous Sagittarius A at a speed of 5 000 km/s (that is to say 200 times faster than the Earth’s movement around the sun). How can an energy emission of such enormous power be explained? Reinhard Genzel, Director of the Max-Planck Institute for Extraterrestrial Scientists put forward the hypothesis that such a phenomenon might Physics (MPE) in Garching, Germany, an active member of the team, be related in some way to black holes, those objects postulated in explains: “The mass of the star S2, and above all its perfectly elliptical cosmological theories derived from modern physics. One might describe orbit, which has been observed with great precision, imply that the centre them as strange ‘zones’, fields of attraction situated at various points in of attraction located at one of the focal points of its orbit has an enormous the universe which ‘capture’ or ‘suck in’ stars passing within reach. mass. The mass of this object must be 2.7 million times that of our own These objects are so dense that not even light can escape from them. sun within a tiny volume no more than 10 light-minutes in diameter – We now know that black holes do indeed exist, and that the energy they a little less than the orbit of Venus, the second closest planet to the sun.” sporadically emit – corresponding to the phenomenon of the quasar These features being compatible with no other phenomenon except a which is associated with them – actually comes from the matter or stars black hole, the final proof had thus been found that Sagittarius A is they have absorbed. When a star falls into a black hole’s field of attraction, indeed our galaxy’s central supermassive black hole. ESO RTD info Special Issue: EIROforum February 2007 41

Proof – in a falling star

Other recent discoveries demonstrate that the era of direct observation of the physics of black holes is well and truly with us. On 8 May 2003 one of the astronomers in Genzel’s team, gazing at the control screen of his giant telescope, was suddenly startled by the presence of an unexpected star. He received a second surprise, just a few minutes later, when the star suddenly disappeared. The team had just observed – for the first time ever – a very intense flash in near infrared, at precisely the location of the supermassive black hole at the centre of our galaxy. This wavelength of radiation matched the signature of an accretion of heated matter which, during its ‘fall’ into the black hole, begins to heat up and thus give off near infrared rays. After years of research, therefore, the elusive evidence of absorption of matter by a black hole had finally been found. Hitherto no one had actually witnessed this last signal from matter caught by a black hole and crossing the point of no return towards an unknown destiny. The movement of a star around the supermassive black hole at the centre of the Milky Way: on the left, Sagittarius (SgrA*) and S2; on the right, diagram of the orbit of S2 around SgrA*, as observed between 1992 and 2002. A video of Sagittarius A and S2 can be downloaded from the ESO website: www.eso.org/outreach/press-rel/pr-2002/video/vid-02-02.mpg © ESO

The most striking result of this observation was that this emission varied very rapidly in intensity in just a few minutes, proving that these infrared Fine-tuning signals must come from a miniscule region. This zone is situated right at the frontier of the black hole, beyond which no more radiation can The Yepun telescope, one of the four making up the VLT at escape. The phenomenon also reveals the existence of periodicity in the Mount Paranal in Chile, is equipped with NaCo and SINFONI radiation, due to the spiralling movement of the matter orbiting the black adaptive optics systems. This technology compensates for hole before vanishing within it. It must revolve extremely rapidly. “This is defects in the image due to atmospheric disturbances by a major discovery,” adds Reinhard Genzel, “which allows us to confirm distorting the mirror and producing an exact opposite of the current theories about black holes. Until recently such a possibility was still unimaginable.”

When astronomy meets theory

21st century astronomy concerns itself not only with questions of astro- physics – such as cosmic inflation, dark matter, dark energy and so on – but also with the great questions of physics at its most theoretical. Thus one can now imagine testing, by observation, the theory of quantum gravitation, the evolution of the cosmos, the Big Bang itself, or even the stability of fundamental constants throughout the history of the universe. In just fifteen years staggering progress has been made. One of the next steps will be to understand when and how these supermassive black holes were formed, and why almost every large galaxy seems to have one. The VLT's Yepun telescope and its laser beam, creating an “artificial star”. © ESO defect; combining the two effects cancels both out. This is done with the assistance of a star occupying a predictable position in the observation field, which serves as a fixed point of reference. As soon as the tiny image of that reference point, the star, becomes distorted or unclear, ultra-rapid servo - mechanisms (performing 1000 operations per second on a For more information distorting mirror within the instrument) restore its ‘clarity’, www.eso.org and thereby that of the rest of the field of observation. When astronomers are observing an area of space where no reference star is available, they make use of an artificial star. This new feat of technology was introduced in 2006. A powerful Contact laser beam (with a precise wavelength) stimulates the sodium Reinhard Genzel atoms present in large numbers in a layer of the atmosphere about [email protected] 90km above the Earth’s surface, generating a characteristic bright light. 42 RTD info Special Issue: EIROforum February 2007 ESO

The message of the gamma-ray bursts

It all began during the cold war. The American military had placed in orbit a veritable armada of satellites capable of detecting gamma rays in order to ascertain whether the Soviets were breaching the nuclear test ban treaty. No explosion was detected in the atmosphere, but instead mysterious flashes were seen coming from space. It was subsequently realised that these were fleeting and random traces of some of the most violent releases of energy to have occurred in the universe since the Big Bang.

amma-ray bursts occur most notably with the momentary appearance A double phenomenon of supernovae and hypernovae – the cataclysmic collapses of Gmassive stars which mark the birth of a black hole. Satellites watch 29 March 2003 was a lucky day for astronomers. A gamma-ray burst vigilantly for these dazzling phenomena and as soon as the message is detected by the American HETE-2 satellite was immediately confirmed passed to ESO’s VLT (Very Large Telescope) in Chile, it focuses on the by ground-based observatories which spotted a new source of visible event to analyse it and decipher its mysteries. light coming from the same direction. In the following hours the VLT The energy unleashed in just a few seconds in these extraordinary Kueyen telescope, equipped with the UVES spectrograph, established the phenomena far exceeds that released by the sun during its life of more spectrum of this new cosmic event. From the red shift the astronomers than 10 billion years. Only the Big Bang itself produced more energy. were able to estimate the distance of the event, which turned out to be All Gamma-Ray Bursts (GRBs) are extragalactic. They come from very relatively close – 2 650 million light-years away. far away – at ‘cosmological’ distances – are distributed throughout the Making regular observations of the spectral characteristics of this new universe, last from a few milliseconds to fifteen minutes and arrive light source over the following months, astronomers gradually saw the without warning. Since they explode into being so unexpectedly, scientists spectrum of a hypernova appear. They also discovered that the light find it hard to study them and understand their astronomical significance. signal was slowly weakening. This scenario conformed to the hypothesis To catch them, you need to be very, very fast. of a light flash like that of a hypernova resulting from the explosion of a

The VLT – fast and flexible

A giant telescope, powerful enough to observe these events, can’t be manipulated like a pair of binoculars. One of the great strengths of the VLT is that it can zoom in on its target in just a few minutes, positioning itself for in-depth observation. Since 1997, with the invaluable assis- tance of satellites capable of detecting gamma-ray sources, several dozen GRBs have been recorded, adding a little more to our knowledge of the origin of the largest of these mysterious gamma-ray bursts. It is thanks to the VLT that astronomers have been able to establish the causal relationship between these flashes and the fluctuating appearance of supernovae and hypernovae, those “new stars” which are extraordinarily bright but whose brilliance rapidly diminishes. However, the name given to these phenomena, which have long aroused the curiosity of astronomers (1), is deceptive. Observations made in the 20th century – particularly observations of the supernova relatively close to Earth in the Large The demise of the hypernova – Two images, in visible light, of gamma-ray Magellanic Cloud which was studied in 1987 – established that these burst GRB 030329, observed on 3 April 2003 (four days after the events were not the “birth of a new star”, but cataclysmic occurrences appearance of the burst), and 1 May 2003. They clearly show the produced by the gravitational collapse of massive stars into their own core. weakening of the optical afterglow, compatible with the behaviour of a hypernova. © ESO ESO RTD info Special Issue: EIROforum February 2007 43

The neutron star scenario – Astronomers have a very different version of events from that concerning hypernovae when it comes to explaining the origin of very short gamma-ray bursts. The scenario is based on the reciprocal attraction of two stars orbiting around one another, in a trajectory that gradually brings them closer and closer. The whole process ends in a stellar explosion in which two jets of plasma are emitted. If one of these jets is pointing towards Earth, it can be seen as a brief gamma-ray burst (artist’s impression). © ESO

very large star at the end of its life. Astrophysicists were able to use these This model implies a star with a mass more than 25 times that of our spectra to establish the moment at which this cataclysmic event must sun, which has converted all its hydrogen into helium and has shed its have occurred – a moment which proved to have coincided with the outermost layers (what astronomers call a Wolf-Rayet star) and which is appearance of the gamma-ray burst. This was nothing less than decisive reaching a stage where the depleted radiation energy no longer confirmation that the two events were connected. In reality, they were one balances the gravitational pressure. The core of the star suddenly and the same event, first observed in gamma rays and then in visible light. begins to collapse in on itself, forming a black hole and at the same time sending out a jet of plasma travelling at enormous speed. This jet crosses the matter within the outer layers of the star, which are hurled The ‘collapsar’ model out into space by stellar winds consisting of newly formed radioactive nickel-56. “The violent light so integral to the concept of the hypernova “GRBs and hypernovae are therefore two facets of the same astronomical is then ‘merely’ a superficial phenomenon, which one might compare object/event,” emphasises Bruno Leibundgut, a researcher at ESO. The to the last flames of a dying star,” continues Bruno Leibundgut. “And it theory favoured by astrophysicists to explain ‘long’ gamma-ray bursts – is at the heart of this process leading to the formation of a black hole, in there are also very short bursts, lasting about a second, for which diffe- the emission of the jet of plasma, that the gamma flash is emitted.” rent interpretations have been put forward – is the ‘collapsar’ model.

(1) References to these phenomena can be found in astronomical documents of the 11th century, both in China and in the West. Tycho Brahé and Johannes Kepler each had the opportunity in their time to observe the two supernovae in the constellations of Cassiopeia (1572) and Ophiuchus(1604).

The Universe’s first steps

A number of gamma-ray bursts come from distances greater than 12.5 billion light years away, in the remotest of galaxies, formed when the universe was still very young. As they are associated with hypernovae, the cataclysmic demise of massive stars, at a time when the Universe was still in its ‘infancy’, presents an exciting challenge to astronomers, offering them a new approach to a better understanding of its nature and evolution. The intrinsic ‘standard’ luminosity of certain hypernovae, in particular, provides a new way of measuring the great For more information distances of the universe, and thus the energy density of http://www.eso.org/outreach/press-rel/pr-2005/pr-26-05-p2.html its component parts. They thus have a part to play in the http://fr.wikipedia.org/wiki/Sursaut_gamma great current questions of astrophysics, such as dark matter http://132.166.172.2/fr/magazine/dossier_sursauts_gamma/index.htm (the existence of which is necessary to explain the movement of galaxies, which cannot be explained by reference to ‘visible’ matter alone), or dark energy, an unknown form of energy deemed necessary to explain the accelerating expansion of the Universe. Contact Bruno Leibundgut [email protected] KI-AB-06-S01-EN-C 44 RTD info Special Issue: EIROforum February 2007 ESO

HARPS – an ultra-sensitive spectrometer

This method of detection requires the use of ultra-sensitive spectrometers. The search ESO has therefore developed the HARPS (High accuracy radial velocity planet searcher), the most effective ‘planet-seeking’ spectrometer in the world, installed at one of the telescopes at the La Silla observatory in Chile. Its extraordinary sensitivity allows it to detect a change in the for exoplanets velocity of a star as slight as one metre per second. The actual shift in the position of the lines on the spectrum examined by the astronomer is in the order of a fraction of a micron. In 1995 Michel Mayor and Didier Queloz, astronomers at A number of discoveries made possible by HARPS have recently caused the Geneva Observatory, announced proof of the existence much excitement in the astronomical community. One such discovery of a planetary mass half that of Jupiter in orbit around the was that of a small “solar system” of three planets orbiting HD69830, a solar-type star 51 Pegasi. This discovery triggered a search star 40 light years away in the Puppis constellation. Two of these newly- discovered planets would appear to be bodies of rock with a mass close for exoplanets, non-stellar objects orbiting another star like to that of Neptune (17 times that of Earth) and thus much less dense our sun, more than 200 of which have so far been identified. than Jupiter (which ‘weighs’ 318 times more than Earth). To this day, of all remote systems, this trio of planets is the one most closely resembling our own solar system.

The enigma of the birth of planets

More than 200 “identified planetary objects” have been discovered over the last eleven years. They are distributed in a homogenous fashion in all parts of the skies – so the solar system is not an exception in the universe. The most numerous of these objects are Jupiter-type planets, massive, hot and gaseous, and orbiting close to their star. It is true that the nature of the main instruments available at present makes it more likely that larger planets will be detected (the disturbance of the star being more significant and the rapid frequency of revolutions easier to observe). As the techniques used continue to be refined, however, it is more than likely that the number of smaller planets detected will increase. Moreover, as Gero Rupprecht, a member of the HARPS team, explains, “The question of the origins of planetary systems is raised by the information gathered on Jupiter-type exoplanets. Are they formed in the vicinity of their star? Or did they form elsewhere and then move towards the star? What astronomers and astrophysicists are trying to understand here is the very dynamic by which planetary systems come into being.” This new field of research can look forward to valuable new data when the E-ELT comes into operation in about twelve years’ time. This giant telescope will be equipped with a data-collecting surface with a diameter of between 30 m and 60 m. It will be able to measure variations in star velocity with incredible accuracy, to within a few centimetres per second, taking precision to its very limits. Furthermore, astronomers will April 2005. The first exoplanet (bottom left) to be photographed directly, be able to listen to the background noise generated by stars, whose thanks to one of ESO’s VLTs. The planet is in orbit around the brown dwarf movement is also influenced by its own activity. star 2M1207b (centre right) at a distance twice that separating Neptune from the sun. It was possible to obtain this image because this brown dwarf is only 100 times brighter than the planet (whereas our own sun is a billion times brighter than the Earth). © ESO For more information rawing on a whole year of observations made at the Observatory of www.eso.org/outreach/press-rel/pr-2006/pr-19-06-add.html Haute Provence, Michel Mayor and Didier Queloz clearly established www.eso.org/gen-fac/pubs/esaesowg/espwg_report.pdf Dthat the velocity of the star 51 Pegasi was subject to periodic fluctuations, which could be attributed to the presence of a large planet in orbit around it. The method used by these researchers was to measure Encyclopaedia of extra-solar planets the radial velocity, i.e. to observe disturbances in the star’s displacement http://exoplanet.eu/ – sometimes in one direction, sometimes in another – induced by the planet and proportional to its mass. The oscillating variation in the velocity of the star affects the light which reaches Earth and the spectral absorption lines shift due to the Doppler Effect, sometimes towards the blue and Contact sometimes towards the red end of the spectrum. Gero Rupprecht [email protected]