INTERNATIONAL SPACE SCIENCE INSTITUTE SPATIUM Published by the Association Pro ISSI No. 24, February 2010 Editorial One might consider space science Space science helps us to under­ unrelated with our human history. stand the miracle of our existence. Impressum This may be one of the reasons why You, dear reader of Spatium, know space science is at the core of the that nothing could be more wrong. European Space Agency ESA (of Without taking into consideration which Switzerland is a founding the cosmic past, our presence here on member) and this is also why our SPATIUM Earth appears to be a mere matter of Pro ISSI association invited Pro­ Published by the course. lt is on the stage of space fessor David Southwood, Director Association Pro ISSI science that our life reveals itself as of ESA’s Science Programme, to the result of events commencing present the current status of the right in the universe’s earliest mo­ programme together with his ments. Take, for example, water, our visions for the years to come. The body’s major constituent: it consists Cosmic Vision, ESA’s master plan Association Pro ISSI of two hydrogen atoms united with for space science, is federating the Hallerstrasse 6, CH­3012 Bern one oxygen atom. While the first European skills together with those Phone +41 (0)31 631 48 96 come unaltered from the unimagin­ of other space­faring nations to see able events in the Big Bang, some address jointly the most fascinating www.issibern.ch/pro­issi.html 14 billion years ago, the latter is the topics in space research. for the whole Spatium series result of nuclear fusion processes in stars that shined and died long before The present issue of Spatium sum­ President our solar system saw the light of the marizes Prof. Southwood’s talk as Prof. Klaus Pretzl day. No doubt: our roots are deeply well as the Agency’s Cosmic Vision University of Bern anchored in the cosmos’ distant past. plan. We are indebted to Prof. Rudolf von Steiger, Director at Layout and Publisher Not only, though. Take for instance ISSI, who cared about the scientific Dr. Hansjörg Schlaepfer the Sun: for 4.6 billion years our correctness of the present text. CH­6614 Brissago daytime star has delivered the warmth enabling life to evolve on The present issue of Spatium is also Printing Earth. Still, like every medal, the a summary of its forerunners; with Stämpfli Publikationen AG Sun has two facets as well: it emits the Cosmic Vision in mind, it sets CH­3001 Bern not only the visual light, to which the stage for all the fascinating re­ our eyes are so well adapted, but also sults to be reported in future issues ultraviolet radiation that is harmful of Spatium. to living cells. This dangerous part of the Sun’s radiation creates the Brissago, February 2010 ozone layer, high above our heads in Hansjörg Schlaepfer the atmosphere, whereby it is sorted out while the rest passes freely down Front Cover to us earthlings: our existence de­ A pilgrim transcending the medi­ pends most fundamentally also on eval lore is shown in this magnifi­ the processes taking place hic et cent wood engraving first published nunc in our cosmic front yard. These in L’atmosphère: météorologie populaire, are but two examples of a chain of by Camille Flammarion, Paris 1888. events in the history of the universe The original is attributed to an to which humans are just one re­ anonymous artist at the beginning sponse of Nature. of the Renaissance. SPATIUM 24 2 COSMIC VISION1 Hansjörg Schlaepfer, Brissago ESA was founded in 1975 not least Introduction based on the initiative of Swiss • How did everything begin? scientists and politicians to foster European efforts to explore space • What are the basic laws of One might think that scientists for peaceful purposes. From the physics? know what is to be known about very beginning, space research has • Are we really alone? the universe. Since the dawn of been the very core of ESA and mankind, humans have looked at the overwhelming success of its • What makes the solar system the sky and tried to understand the scientific spacecraft has won it tick? mysterious world out there. Thou­ worldwide acknowledgement as sands of years ago, an early society one of the leading space agencies. erected the gigantic stones in Stone­ henge, Great Britain, exactly in line With the intention of harmonizing Obviously, these questions are not with the midsummer sunrise. Four the endeavours of European aca­ specifically European; rather they hundred years ago, Galileo Galilei demic and industrial communities, are of interest for thinking humans directed his cannochiale to the sky the Agency formulated the Hori­ all over the world. It is, therefore, that uncovered a world never seen zon 2000 long­term plan for space one of the key elements of the Cos­ before by human eyes. Fifty years science in 1984 that defined the pri­ mic Vision plan to seek co­opera­ ago, Sputnik I initiated a new era orities and programmes for the sub­ tion with other space agencies in that led to today’s fleet of spacecraft sequent 10 to 20 years. Its succes­ order to not only benefit from the rushing through space in search of sor, the Horizon 2000+ plan, was experience and skills gained else­ new discoveries. All these en­ approved ten years ago; it consti­ where but also to share the costs of deavours are nourished by the fas­ tutes the programmatic foundation the anticipated missions. Beyond cinating results of space research of the scientific satellites and space paving the way for fascinating re­ that still do not become increasingly telescopes currently in orbit. Build­ sults, the Cosmic Vision programme sparse, but rather increasingly excit­ ing on past success to address the therefore contributes also to fur­ ing: Nature’s wealth of mysteries is scientific, intellectual and techno­ thering the understanding of boundless. logical challenges of tomorrow, scientists and engineers all over the ESA made another planning cycle world. Now then, what are the remaining in the first years of this new millen­ secrets of the universe scientists nium which resulted in the Cosmic would like to know? Where do they Vision plan outlined in the present expect the most enlightening dis­ issue of Spatium. It is basically built coveries to be made in the years to around the following four main ar­ come? What are the key questions eas of space research: that the European Space Agency (ESA) intends to address in the fu­ ture? The present issue of Spatium aims at providing some answers to these questions. 1 The present issue of Spatium is loosely based on a lecture given by Professor David Southwood for the Pro ISSI audience on 24 March 2009 and reported by Dr. Hansjörg Schlaepfer, Brissago. SPATIUM 24 3 The Early Universe most phantastic results of recent How Did Every- space research to probe this first thing Begin? The Big Bang model is a physical light and to observe the universe in concept of how the universe might its earliest infancy. have come into being4,5. It has won wide acceptance as it is firmly This light is called cosmic micro­ OMNIUM RERUM underpinned by observations one wave background radiation as it PRINCIPIA PARVA SUNT2 can make today. Yet, it fails to de­ presents itself today as a microwave scribe the very earliest – and most radiation from all over the sky. It was Marcus Tullius Cicero3 crucial – instances when time, en­ found accidentally by Arno Penzias6 ergy and matter were born. At that and Robert Wilson7 with a ground­ moment, the physical properties of based detector in 1964. While ini­ This is admittedly not quite a new the emerging universe exceeded by tially it was thought to be isotropic, question. Rather, generations be­ far the grasp of our understanding. later spacecraft equipped with more fore us have wondered already Some split second later, however, it sensitive instruments revealed tiny about how this world might have expanded and cooled down and its radiation (or equivalently tempera­ come into being. Great thinkers in parameters entered the reach of ture) differences in the order of all cultures have made their specu­ contemporary physics; from now 0.000,1 °C, see Fig. 1. The point here lations ranging from the cyclic on, the evolution of the universe is that these early fine structures are upcoming of what has been here becomes understandable. Not quite, essential for our existence as a per­ forever to a universe with both, a however, as we will see later. fectly homogeneous universe would definite beginning and a definite be unable to form inhomogeneities end. Cosmology, today, advocates a such as stars and planets. definite beginning, as described by The First Light the Big Bang model, while the The primary inhomogeneities stem future of the universe is still under A few minutes after the Big Bang, from quantum fluctuations in the debate. neutrons combined with protons to very early universe, which grew form the first deuterium and he­ with time to macroscopic structures lium nuclei. These are the first by gravitational attraction. How­ building blocks of matter as we ever, the visible matter in the uni­ know today. About 380,000 years verse is insufficient for that process, later, the temperature had cooled so scientists have to resort to what down to a value that allowed these they call Dark Matter8 to explain nuclei to bind electrons resulting in these fine structures. Dark Matter the first neutral atoms. That was a designates a hypothetical form of great event as it permitted light to matter that cannot be seen with propagate freely through space from electromagnetic waves – hence the now on: the universe became trans­ attribute dark – but can be inferred parent.