DOCSLIB.ORG

The Commonplace and Unexpected from High Energy Physicists

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Commonplace and Unexpected from High Energy Physicists 186 Nature Vol. 250 July /9 1974 leptons only in weak or electromagnetic decays, not in their strong collisions. The commonplace and unexpected A group from CERN, Columbia and Rockefeller Universities in New York, from high energy physicists and from Saclay in Franoe, working at from David !. Miller the CERN Intersecting Storage Rings in Geneva, has now found convincing LAST year's wonder has become this with all neutral-current experiments, evidence that electrons are directly pro­ year's commonplace. On July 1, the the final-state neutrino in each event duced in proton-proton collisions at opening day of the International Con­ was not observed. The numbers are too the very highest observed energies. ference on High Energy Physics at small, to date, to do more than to Another group from Columbia, work­ Imperial College, London, five separate establish the existence of these pro­ ing at the Fermi National Laboratory new pieces of evidence for neutral cesses. Experimenters from CERN near Chicago, has seen the same sort of weak currents were reported. More­ obtained similar results by studying effect, with both electrons and muons over, the two groups who had published neutrino interaction on the free protons coming from proton-proton collisions previously reported greatly improved in propane, using film which was taken at somewhM lower energies. A Chicago, statistics (see Nature, 245, 119; 1973 7 or 8 years ago, before the existence Harvard, Pennsylvania and Wisconsin and 249, 211; 1974 for discussions of of neutral currents was even suggested. group also has seen direct muon pro­ the first neutral-current result, from It demonstrates that there should be duction at the Fermi Laboratory, and the Gargamelle bubble chamber at a great deal of useful data to be ob­ direct muon production has been CERN, Geneva and of the early tained from the next Gargamelle run, reported from the even lower energy Harvard/Fermi Laboratory results). with a propane filling and a more accelerators at Serpukhov in the Soviet The most striking of the new pieces intense neutrino beam. Union and at Brookhaven, New York. of data comes from a group at the There can now be no doubt that All of these data have, of course, been California Institute of Technology, neutrinos and antineutrinos interact corrected for indirect muon production which used an array of counters, spark with nucleons (that is, protons and by means of the weak decays of mesons. chambers and magnets in a neutrino neutrons) in two distinct ways. The In every case the ratio of direct lepton beam at the Fermi National Accelera­ charged-current mode is more copious, production to pion production is about tor Laboratory (FNAL). The momen­ but the neutral-current mode, in which 1 to 10,000. The ratio does not vary tum of their neutrino beam is known another neutrino goes off afterwards much over the large energy span of better than in the first Harvard-FN AL rather than a charged muon, is well these different machines. It al!lo seems experiment, and they have a clearer established. It is even becoming pos­ roughly con!ltant as the transverse com­ technique for identifying events with­ sible to put realistic limits on the ponent of the lepton momentum, per­ out fast muons. Their ratio for muon­ 'Weinberg angle', a parameter which pendicular to the incoming protons, is less neutrino events (neutral-current governs the relative strength of the varied from 2 to 5 GeV I c. mode) to events with a muon (charger­ charged and neutral currents in the Two sorts of explanation have been current mode) is 0.22 to l. With an simplest unified theory of weak and suggested for direct lepton production; antineutrino beam the equivalent ratio electromagnetic interactions. the revolutionary or the merely surpris­ is 0.33 to 1. Although their neutrino One interesting question still awaits ing. One revolutionary explanation beam momenta are around 45 GeVIc a definite answer; that is, how do requi1res that 'charmed' particles are or 120 GeV /c, compared with around neutrinos and antineutrinos interact being produced, and decaying rapidly 1 to 10 GeV /c in Gargamelle, this with electrons? The Gargamelle col­ to normal particles including muons neutrino ratio is very close to the laboration reported the observation of or electrons. 'Charm' is a postulated latest Gargamelle figure, and the anti­ two events in which an electron ap­ new quantum number, similar to neutrino ratio is not alarmingly dif­ pears to have been produced by an the old-established 'strangeness' quan­ ferent, considering the greater uncer­ antineutrino interaction. Although the tum number. It is needed to explain, tainties involved in small antineutrino calculated background is small, there among other things, the absence statistics. A collaboration of 'East can be no certainty in the observation of strange-particle production in Coast' university groups, working at of such a small signal. But the rate is neutral-current weak interactions. The the 29 GeV /c Brookhaven accelerator roughly what would be expected with­ merely surprising explanation requires near New York, has also seen a clear in the framework of the simplest that most of the pion production neutral-current signal in a spark theory, using a value for the Weinberg in high energy proton-proton collisions chamber experiment. angle which is consistent with the actually comes from the production of Two groups reported the observation neutrino-nucleon experiments. This is massive resonances which decay to of neutral-current events with all the the first experimental evidence that the pions by the strong interaction. Some final-state particles identified. In Gar­ neutral neutrino current might inter­ of -thelle resonances, in particular the gamelle and in the big spark chamber act with electrons as well as with 'rho', the 'omega' and the 'phi' known arrays, this has been difficult, since the protons. as the 'vector mesons', also decay neutrinos interact with the protons or occasionally by means of the electro­ neutrons of a heavy nucleus. At the Muon puzzles magnetic intera·ction to a pair of elec­ Argonne Laboratory, near Chicago, There was s·peculation at the meeting trons or a pair of muons. Pre.Jiminary a group from Argonne, Concordia Col­ about both new elementary particles calculations, using vector meson decays, lege and Purdue University has used and new interactions. One new effect is give a lepton to pion ratio of about the 12-foot bubble chamber, filled with the direct production of charged leptons 1 >to 100,000. Nobody knows yet liquid hydrogen or deuterium, to from hadron collisions. The leptons­ whether the ext'fa factor of 10 can be identify about 14 events in which a electron, muon and neutrino--have found to inake this calculation match neutrino struk a single proton (or a never been observed to take part in the observed rate. But even if the factor neutron in deuterium). The final state strong interactions. The hadrons-the can be found, and a revolutionary in each of these events contained a proton and neutron, the hyperons, the explanation is not needed, ideas of positive or a neutral pion, plus a recoil mesons and all of the resonant states­ pa.r>ticular production at high energies neutron or proton (and lllso a visible are the only known strong·ly interacting will have been radically changed. 'spectator' proton, in deuterium). As particles. They were thought to produce The Fermi Laboratory and Harvard © 1974 Nature Publishing Group Nature Vol. 250 July 19 1974 187 neutrino experiment has revealed two the western North America trench and propagation in the upper mantle be­ puzzling muon events of quite a strike-slip motion commenced along neath the relevant station. different kind. Each seems to be the the San Andreas fault. In this way it is The residual-sphere for station LON result of the interaction of a 150-GeV thought, the plate boundary along in the Cascades in Washington (refer­ neutrino in their apparatus, producing we,stern North America began to enced to BMO, Blue Mountain two muons and a shower of hadrons. to change from a subduction zone to a Observatory 1to the east) failed to Ordinary 'charged-current' neutrino transform fault. There is evidence from indicate any systematic trends in resi­ interactions contain one final-state seismic reflection s·tudies -of the conti­ duals. If a high velocity slab lies in the muon, and neutral-current events have nental margin, from the occurrence of upper mant.le beneath western Washing­ no muons. As a theorist remarked a·t subcrustal earthquakes, from andesitic ton and if its upward projection cut the conference: "taking preliminary volcanism in the Cascades and from the Earth's surface near LON, an results seriously is a weU known way marine magnetic anomalies that north eastward-dipping band of negative of making a fool of yourself". Never­ of the Mendocino fracture zone sub­ residuals (early arrivals) might be theless, there is much speculation that duction may still be occurring very expected. No such band was observed. these dimuons could be due to the decay slowly. South of Cape Mendocino, how­ But for station pairs based on the three of a totally new kind of pal1ticle. Some ever, subduction has ceased, although primary stations in California (MIN in say 'charmed' particles again; some say Atwater (Bull. Geol. Soc. Am., 81, 3513; the southern Cascades, ORV and JAS it may be the 'intermediate boson' that 1970) has concluded that the cessation along the western edges of the Sierra carries the weak force, a sort of heavy may have occurred no more than a few Nevada), a group of consistently nega­ photon; some say it is a heavy lepton million years ago.
Load more

Recommended publications
  • CERN Courier–Digital Edition
    CERNMarch/April 2021 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the March/April 2021 issue of CERN Courier. Hadron colliders have contributed to a golden era of discovery in high-energy physics, hosting experiments that have enabled physicists to unearth the cornerstones of the Standard Model. This success story began 50 years ago with CERN’s Intersecting Storage Rings (featured on the cover of this issue) and culminated in the Large Hadron Collider (p38) – which has spawned thousands of papers in its first 10 years of operations alone (p47). It also bodes well for a potential future circular collider at CERN operating at a centre-of-mass energy of at least 100 TeV, a feasibility study for which is now in full swing. Even hadron colliders have their limits, however. To explore possible new physics at the highest energy scales, physicists are mounting a series of experiments to search for very weakly interacting “slim” particles that arise from extensions in the Standard Model (p25). Also celebrating a golden anniversary this year is the Institute for Nuclear Research in Moscow (p33), while, elsewhere in this issue: quantum sensors HADRON COLLIDERS target gravitational waves (p10); X-rays go behind the scenes of supernova 50 years of discovery 1987A (p12); a high-performance computing collaboration forms to handle the big-physics data onslaught (p22); Steven Weinberg talks about his latest work (p51); and much more. To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING ATLAS spots rare Higgs decay Weinberg on effective field theory Hunting for WISPs CCMarApr21_Cover_v1.indd 1 12/02/2021 09:24 CERNCOURIER www.
    [Show full text]
  • CERN Celebrates Discoveries
    INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 43 NUMBER 10 DECEMBER 2003 CERN celebrates discoveries NEW PARTICLES NETWORKS SPAIN Protons make pentaquarks p5 Measuring the digital divide pl7 Particle physics thrives p30 16 KPH impact 113 KPH impact series VISyN High Voltage Power Supplies When the objective is to measure the almost immeasurable, the VISyN-Series is the detector power supply of choice. These multi-output, card based high voltage power supplies are stable, predictable, and versatile. VISyN is now manufactured by Universal High Voltage, a world leader in high voltage power supplies, whose products are in use in every national laboratory. For worldwide sales and service, contact the VISyN product group at Universal High Voltage. Universal High Voltage Your High Voltage Power Partner 57 Commerce Drive, Brookfield CT 06804 USA « (203) 740-8555 • Fax (203) 740-9555 www.universalhv.com Covering current developments in high- energy physics and related fields worldwide CERN Courier (ISSN 0304-288X) is distributed to member state governments, institutes and laboratories affiliated with CERN, and to their personnel. It is published monthly, except for January and August, in English and French editions. The views expressed are CERN not necessarily those of the CERN management. Editor Christine Sutton CERN, 1211 Geneva 23, Switzerland E-mail: [email protected] Fax:+41 (22) 782 1906 Web: cerncourier.com COURIER Advisory Board R Landua (Chairman), P Sphicas, K Potter, E Lillest0l, C Detraz, H Hoffmann, R Bailey
    [Show full text]
  • A Time of Great Growth
    Newsletter | Spring 2019 A Time of Great Growth Heartfelt greetings from the UC Riverside Department of Physics and Astronomy. This is our annual newsletter, sent out each Spring to stay connected with our former students, retired faculty, and friends in the wider community. The Department continues to grow, not merely in size but also in stature and reputation. For the 2018-2019 academic year, we were pleased to welcome two new faculty: Professors Thomas Kuhlman and Barry Barish. Professor Kuhlman was previously on the faculty at the University of Illinois at Urbana-Champaign. He joins our efforts in the emerging field of biophysics. His research lies in the quantitative imaging and theoretical modeling of biological systems. He works on genome dynamics, quantification of the activity of transposable elements in living cells, and applications to the engineering of genome editing. Professor Barry Barish, who joins us from Caltech, is the winner of the 2017 Nobel Prize in Physics. He brings great prestige to our Department. Along with Professor Richard Schrock of the Department of Chemistry, who also joined UCR in 2018, UCR now has two Nobel Prize winners on its faculty. Professor Barish is an expert on the detection and physics of gravitational waves. He has been one of the key figures in the conception, construction, and operation of the LIGO detector, where gravitational waves were first discovered in 2015, and which led to his Nobel Prize. He is a member of the National Academy of Sciences and the winner of many other prestigious awards. The discovery of gravitational waves is one of the most exciting developments in physics so far this century.
    [Show full text]
  • The AWAKE Acceleration Scheme for New Particle Physics Experiments at CERN
    AWAKE++: the AWAKE Acceleration Scheme for New Particle Physics Experiments at CERN W. Bartmann1, A. Caldwell2, M. Calviani1, J. Chappell3, P. Crivelli4, H. Damerau1, E. Depero4, S. Doebert1, J. Gall1, S. Gninenko5, B. Goddard1, D. Grenier1, E. Gschwendtner*1, Ch. Hessler1, A. Hartin3, F. Keeble3, J. Osborne1, A. Pardons1, A. Petrenko1, A. Scaachi3, and M. Wing3 1CERN, Geneva, Switzerland 2Max Planck Institute for Physics, Munich, Germany 3University College London, London, UK 4ETH Zürich, Switzerland 5INR Moscow, Russia 1 Abstract The AWAKE experiment reached all planned milestones during Run 1 (2016-18), notably the demon- stration of strong plasma wakes generated by proton beams and the acceleration of externally injected electrons to multi-GeV energy levels in the proton driven plasma wakefields. During Run 2 (2021 - 2024) AWAKE aims to demonstrate the scalability and the acceleration of elec- trons to high energies while maintaining the beam quality. Within the Physics Beyond Colliders (PBC) study AWAKE++ has explored the feasibility of the AWAKE acceleration scheme for new particle physics experiments at CERN. Assuming continued success of the AWAKE program, AWAKE will be in the position to use the AWAKE scheme for particle physics ap- plications such as fixed target experiments for dark photon searches and also for future electron-proton or electron-ion colliders. With strong support from the accelerator and high energy physics community, these experiments could be installed during CERN LS3; the integration and beam line design show the feasibility of a fixed target experiment in the AWAKE facility, downstream of the AWAKE experiment in the former CNGS area. The expected electrons on target for fixed target experiments exceeds the electrons on target by three to four orders of magnitude with respect to the current NA64 experiment, making it a very promising experiment in the search for new physics.
    [Show full text]
  • Barry Barish and the Gde: Mission Achievable
    INTERVIEW Barry Barish and the GDE: mission achievable The head of the Global Design Effort for a future International Linear Collider talks about challenges past, present and future. Barry Barish likes a challenge. He admits to a complete tendency to go for the difficult in his research – in his view, life is an adventure. Some might say that his most recent challenge would fit well with a certain famous TV series: “Your mission, should you choose to accept it… is to produce a design for the International Linear Collider that includes a detailed design concept, performance assessments, reliable international costing, an industrialization plan, and siting analysis, as well as detector concepts and scope.” Barish did indeed accept the challenge in March 2005, when he became director of the Global Design Effort (GDE) for a proposed International Linear Collider (ILC). He started in a directorate of one – himself – at the head of a “virtual” laboratory of hundreds of physicists and engineers around the globe. To run the “lab” he has set up a small executive committee, which includes three regional directors (for the Americas, Asia and Europe), three project manag- ers and two leading accelerator experts. There are also boards for R&D, change control and design cost. Barish operates from his base at Caltech, where he has been since 1962 and ultimately became Linde Professor of Physics (now emeri- tus). His taste for research challenges became evident in the 1970s, when he was co-spokesperson with Frank Sciulli (also at Caltech) of the “narrow band” neutrino experiment at Fermilab that studied Barish became director of the Global Design Effort for the International weak neutral currents and the quark substructure of the nucleon.
    [Show full text]
  • Gravitational Waves from the Early Universe
    Gravitational Waves from the Early Universe Lecture 1A: Gravitational Waves, Theory Kai Schmitz (CERN) Chung-Ang University, Seoul, South Korea j June 2 – 4 1/21 ◦ 1916: Albert Einstein predicts GWs based on his general theory of relativity ◦ 2016: The LIGO/Virgo Collaboration announces the detection of GW150914 ◦ 2017: Nobel Prize in Physics awarded to Rainer Weiss, Barry Barish, and Kip Thorne → Milestone in fundamental physics, triumph of general relativity → Discovery of a new class of astrophysical objects: heavy black holes in binary systems First direct detection of gravitational waves [Nicolle Rager Fuller for sciencenews.org] 2/21 ◦ 2016: The LIGO/Virgo Collaboration announces the detection of GW150914 ◦ 2017: Nobel Prize in Physics awarded to Rainer Weiss, Barry Barish, and Kip Thorne → Milestone in fundamental physics, triumph of general relativity → Discovery of a new class of astrophysical objects: heavy black holes in binary systems First direct detection of gravitational waves [Nicolle Rager Fuller for sciencenews.org] ◦ 1916: Albert Einstein predicts GWs based on his general theory of relativity 2/21 ◦ 2017: Nobel Prize in Physics awarded to Rainer Weiss, Barry Barish, and Kip Thorne → Milestone in fundamental physics, triumph of general relativity → Discovery of a new class of astrophysical objects: heavy black holes in binary systems First direct detection of gravitational waves [Nicolle Rager Fuller for sciencenews.org] ◦ 1916: Albert Einstein predicts GWs based on his general theory of relativity ◦ 2016: The LIGO/Virgo
    [Show full text]
  • AWAKE! Allen Caldwell Even Larger Accelerators ?
    Swapan Chattopadhyay Symposium April 30, 2021 AWAKE! Allen Caldwell Even larger Accelerators ? Energy limit of circular proton collider given by magnetic field strength. P B R / · Energy gain relies in large part on magnet development Linear Electron Collider or Muon Collider? proton P P Leptons preferred: Collide point particles rather than complex objects But, charged particles radiate energy when accelerated. Power α (E/m)4 Need linear electron accelerator or m large (muon 200 heavier than electron) A plasma: collection of free positive and negative charges (ions and electrons). Material is already broken down. A plasma can therefore sustain very high fields. C. Joshi, UCLA E. Adli, Oslo An intense particle beam, or intense laser beam, can be used to drive the plasma electrons. Plasma frequency depends only on density: Ideas of ~100 GV/m electric fields in plasma, using 1018 W/cm2 lasers: 1979 T.Tajima and J.M.Dawson (UCLA), Laser Electron Accelerator, Phys. Rev. Lett. 43, 267–270 (1979). Using partice beams as drivers: P. Chen et al. Phys. Rev. Lett. 54, 693–696 (1985) Energy Budget: Introduction Witness: Staging Concepts 1010 particles @ 1 TeV ≈ few kJ Drivers: PW lasers today, ~40 J/Pulse FACET (e beam, SLAC), 30J/bunch SPS@CERN 20kJ/bunch Leemans & Esarey, Phys. Today 62 #3 (2009) LHC@CERN 300 kJ/bunch Dephasing 1 LHC driven stage SPS: ~100m, LHC: ~few km E. Adli et al. arXiv:1308.1145,2013 FCC: ~ 1<latexit sha1_base64="TR2ZhSl5+Ed6CqWViBcx81dMBV0=">AAAB7XicbZBNS8NAEIYn9avWr6pHL4tF8FQSEeyx4MVjBfsBbSib7aZdu9mE3YkQQv+DFw+KePX/ePPfuG1z0NYXFh7emWFn3iCRwqDrfjuljc2t7Z3ybmVv/+DwqHp80jFxqhlvs1jGuhdQw6VQvI0CJe8lmtMokLwbTG/n9e4T10bE6gGzhPsRHSsRCkbRWp2BUCFmw2rNrbsLkXXwCqhBodaw+jUYxSyNuEImqTF9z03Qz6lGwSSfVQap4QllUzrmfYuKRtz4+WLbGbmwzoiEsbZPIVm4vydyGhmTRYHtjChOzGptbv5X66cYNvxcqCRFrtjyozCVBGMyP52MhOYMZWaBMi3sroRNqKYMbUAVG4K3evI6dK7qnuX761qzUcRRhjM4h0vw4AaacActaAODR3iGV3hzYufFeXc+lq0lp5g5hT9yPn8Avy+PMg==</latexit> A. Caldwell and K. V. Lotov, Phys.
    [Show full text]
  • Inter Actions Department of Physics 2015
    INTER ACTIONS DEPARTMENT OF PHYSICS 2015 The Department of Physics has a very accomplished family of alumni. In this issue we begin to recognize just a few of them with stories submitted by graduates from each of the decades since 1950. We want to invite all of you to renew and strengthen your ties to our department. We would love to hear from you, telling us what you are doing and commenting on how the department has helped in your career and life. Alumna returns to the Physics Department to Implement New MCS Core Education When I heard that the Department of Physics needed a hand implementing the new MCS Core Curriculum, I couldn’t imagine a better fit. Not only did it provide an opportunity to return to my hometown, but Carnegie Mellon itself had been a fixture in my life for many years, from taking classes as a high school student to teaching after graduation. I was thrilled to have the chance to return. I graduated from Carnegie Mellon in 2008, with a B.S. in physics and a B.A. in Japanese. Afterwards, I continued to teach at CMARC’s Summer Academy for Math and Science during the summers while studying down the street at the University of Pittsburgh. In 2010, I earned my M.A. in East Asian Studies there based on my research into how cultural differences between Japan and America have helped shape their respective robotics industries. After receiving my master’s degree and spending a summer studying in Japan, I taught for Kaplan as graduate faculty for a year before joining the Department of Physics at Cornell University.
    [Show full text]
  • MIT at the Large Hadron Collider—Illuminating the High-Energy Frontier
    Mit at the large hadron collider—Illuminating the high-energy frontier 40 ) roland | klute mit physics annual 2010 gunther roland and Markus Klute ver the last few decades, teams of physicists and engineers O all over the globe have worked on the components for one of the most complex machines ever built: the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, Switzerland. Collaborations of thousands of scientists have assembled the giant particle detectors used to examine collisions of protons and nuclei at energies never before achieved in a labo- ratory. After initial tests proved successful in late 2009, the LHC physics program was launched in March 2010. Now the race is on to fulfill the LHC’s paradoxical mission: to complete the Stan- dard Model of particle physics by detecting its last missing piece, the Higgs boson, and to discover the building blocks of a more complete theory of nature to finally replace the Standard Model. The MIT team working on the Compact Muon Solenoid (CMS) experiment at the LHC stands at the forefront of this new era of particle and nuclear physics. The High Energy Frontier Our current understanding of the fundamental interactions of nature is encap- sulated in the Standard Model of particle physics. In this theory, the multitude of subatomic particles is explained in terms of just two kinds of basic building blocks: quarks, which form protons and neutrons, and leptons, including the electron and its heavier cousins. From the three basic interactions described by the Standard Model—the strong, electroweak and gravitational forces—arise much of our understanding of the world around us, from the formation of matter in the early universe, to the energy production in the Sun, and the stability of atoms and mit physics annual 2010 roland | klute ( 41 figure 1 A photograph of the interior, central molecules.
    [Show full text]
  • The People Who Invented the Internet Source: Wikipedia's History of the Internet
    The People Who Invented the Internet Source: Wikipedia's History of the Internet PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Sat, 22 Sep 2012 02:49:54 UTC Contents Articles History of the Internet 1 Barry Appelman 26 Paul Baran 28 Vint Cerf 33 Danny Cohen (engineer) 41 David D. Clark 44 Steve Crocker 45 Donald Davies 47 Douglas Engelbart 49 Charles M. Herzfeld 56 Internet Engineering Task Force 58 Bob Kahn 61 Peter T. Kirstein 65 Leonard Kleinrock 66 John Klensin 70 J. C. R. Licklider 71 Jon Postel 77 Louis Pouzin 80 Lawrence Roberts (scientist) 81 John Romkey 84 Ivan Sutherland 85 Robert Taylor (computer scientist) 89 Ray Tomlinson 92 Oleg Vishnepolsky 94 Phil Zimmermann 96 References Article Sources and Contributors 99 Image Sources, Licenses and Contributors 102 Article Licenses License 103 History of the Internet 1 History of the Internet The history of the Internet began with the development of electronic computers in the 1950s. This began with point-to-point communication between mainframe computers and terminals, expanded to point-to-point connections between computers and then early research into packet switching. Packet switched networks such as ARPANET, Mark I at NPL in the UK, CYCLADES, Merit Network, Tymnet, and Telenet, were developed in the late 1960s and early 1970s using a variety of protocols. The ARPANET in particular led to the development of protocols for internetworking, where multiple separate networks could be joined together into a network of networks. In 1982 the Internet Protocol Suite (TCP/IP) was standardized and the concept of a world-wide network of fully interconnected TCP/IP networks called the Internet was introduced.
    [Show full text]
  • 50 Years of Pulsars: Jocelyn Bell Burnell an Interview P
    LIGO Scientific Collaboration Scientific LIGO issue 11 9/2017 LIGO MAGAZINE O2: Third Detection! 10:11:58.6 UTC, 4 January 2017 ELL F, H O L P IS L A E ! Y B D O O G 50 Years of Pulsars: Jocelyn Bell Burnell An interview p. 6 The Search for Continuous Waves To name a neutron star p.10 ... and in 1989: The first joint interferometric observing run p. 26 Before the Merger: Spiraling Black Holes Front cover image: Artist’s conception shows two merging black holes similar to those detected by LIGO. The black holes are spinning in a non-aligned fashion, which means they have different orientations relative to the overall orbital motion of the pair. LIGO found a hint of this phenomenon in at least one black hole of the GW170104 system. Image: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet) Image credits Front cover main image – Credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet) Front cover inset LISA – Courtesy of LISA Consortium/Simon Barke Front cover inset of Jocelyn Bell Burnell and the 4 acre telescope c 1967 courtesy Jocelyn Bell Burnell. Front cover inset of the supernova remnant G347.3-0.5 – Credit: Chandra: NASA/CXC/SAO/P.Slane et al.; XMM-Newton:ESA/RIKEN/J.Hiraga et al. p. 3 Comic strip by Nutsinee Kijbunchoo p. 4-5 Photos by Matt Gush, Bryce Vickmark and Josh Meister p. 6 Jocelyn Bell Burnell and the 4 acre telescope courtesy Jocelyn Bell Burnell. Paper chart analysis courtesy Robin Scagell p. 8 Pulsar chart recordings courtesy Mullard Radio Astronomy Observatory p.
    [Show full text]
  • 1 the Warped Science of Interstellar Jean
    The Warped Science of Interstellar Jean-Pierre Luminet Aix-Marseille Université, CNRS, Laboratoire d'Astrophysique de Marseille (LAM) UMR 7326 Centre de Physique Théorique de Marseille (CPT) UMR 7332 and Observatoire de Paris (LUTH) UMR 8102 France E-mail: [email protected] The science fiction film, Interstellar, tells the story of a team of astronauts searching a distant galaxy for habitable planets to colonize. Interstellar’s story draws heavily from contemporary science. The film makes reference to a range of topics, from established concepts such as fast-spinning black holes, accretion disks, tidal effects, and time dilation, to far more speculative ideas such as wormholes, time travel, additional space dimensions, and the theory of everything. The aim of this article is to decipher some of the scientific notions which support the framework of the movie. INTRODUCTION The science-fiction movie Interstellar (2014) tells the adventures of a group of explorers who use a wormhole to cross intergalactic distances and find potentially habitable exoplanets to colonize. Interstellar is a fiction, obeying its own rules of artistic license : the film director Christopher Nolan and the screenwriter, his brother Jonah, did not intended to put on the screens a documentary on astrophysics – they rather wanted to produce a blockbuster, and they succeeded pretty well on this point. However, for the scientific part, they have collaborated with the physicist Kip Thorne, a world-known specialist in general relativity and black hole theory. With such an advisor, the promotion of the movie insisted a lot on the scientific realism of the story, in particular on black hole images calculated by Kip Thorne and the team of visual effects company Double Negative.
    [Show full text]