Exploring the Cosmic Microwave Background All-Encompassing Light from the Early Universe SHAUN AKHTAR
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Physical Cosmology," Organized by a Committee Chaired by David N
Proc. Natl. Acad. Sci. USA Vol. 90, p. 4765, June 1993 Colloquium Paper This paper serves as an introduction to the following papers, which were presented at a colloquium entitled "Physical Cosmology," organized by a committee chaired by David N. Schramm, held March 27 and 28, 1992, at the National Academy of Sciences, Irvine, CA. Physical cosmology DAVID N. SCHRAMM Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 The Colloquium on Physical Cosmology was attended by 180 much notoriety. The recent report by COBE of a small cosmologists and science writers representing a wide range of primordial anisotropy has certainly brought wide recognition scientific disciplines. The purpose of the colloquium was to to the nature of the problems. The interrelationship of address the timely questions that have been raised in recent structure formation scenarios with the established parts of years on the interdisciplinary topic of physical cosmology by the cosmological framework, as well as the plethora of new bringing together experts of the various scientific subfields observations and experiments, has made it timely for a that deal with cosmology. high-level international scientific colloquium on the subject. Cosmology has entered a "golden age" in which there is a The papers presented in this issue give a wonderful mul- tifaceted view of the current state of modem physical cos- close interplay between theory and observation-experimen- mology. Although the actual COBE anisotropy announce- tation. Pioneering early contributions by Hubble are not ment was made after the meeting reported here, the following negated but are amplified by this current, unprecedented high papers were updated to include the new COBE data. -
The Age of the Universe Transcript
The Age of the Universe Transcript Date: Wednesday, 6 February 2013 - 1:00PM Location: Museum of London 6 February 2013 The Age of The Universe Professor Carolin Crawford Introduction The idea that the Universe might have an age is a relatively new concept, one that became recognised only during the past century. Even as it became understood that individual objects, such as stars, have finite lives surrounded by a birth and an end, the encompassing cosmos was always regarded as a static and eternal framework. The change in our thinking has underpinned cosmology, the science concerned with the structure and the evolution of the Universe as a whole. Before we turn to the whole cosmos then, let us start our story nearer to home, with the difficulty of solving what might appear a simpler problem, determining the age of the Earth. Age of the Earth The fact that our planet has evolved at all arose predominantly from the work of 19th century geologists, and in particular, the understanding of how sedimentary rocks had been set down as an accumulation of layers over extraordinarily long periods of time. The remains of creatures trapped in these layers as fossils clearly did not resemble any currently living, but there was disagreement about how long a time had passed since they had died. The cooling earth The first attempt to age the Earth based on physics rather than geology came from Lord Kelvin at the end of the 19th Century. Assuming that the whole planet would have started from a completely molten state, he then calculated how long it would take for the surface layers of Earth to cool to their present temperature. -
Cosmic Background Explorer (COBE) and Beyond
From the Big Bang to the Nobel Prize: Cosmic Background Explorer (COBE) and Beyond Goddard Space Flight Center Lecture John Mather Nov. 21, 2006 Astronomical Search For Origins First Galaxies Big Bang Life Galaxies Evolve Planets Stars Looking Back in Time Measuring Distance This technique enables measurement of enormous distances Astronomer's Toolbox #2: Doppler Shift - Light Atoms emit light at discrete wavelengths that can be seen with a spectroscope This “line spectrum” identifies the atom and its velocity Galaxies attract each other, so the expansion should be slowing down -- Right?? To tell, we need to compare the velocity we measure on nearby galaxies to ones at very high redshift. In other words, we need to extend Hubble’s velocity vs distance plot to much greater distances. Nobel Prize Press Release The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2006 jointly to John C. Mather, NASA Goddard Space Flight Center, Greenbelt, MD, USA, and George F. Smoot, University of California, Berkeley, CA, USA "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation". The Power of Thought Georges Lemaitre & Albert Einstein George Gamow Robert Herman & Ralph Alpher Rashid Sunyaev Jim Peebles Power of Hardware - CMB Spectrum Paul Richards Mike Werner David Woody Frank Low Herb Gush Rai Weiss Brief COBE History • 1965, CMB announced - Penzias & Wilson; Dicke, Peebles, Roll, & Wilkinson • 1974, NASA AO for Explorers: ~ 150 proposals, including: – JPL anisotropy proposal (Gulkis, Janssen…) – Berkeley anisotropy proposal (Alvarez, Smoot…) – Goddard/MIT/Princeton COBE proposal (Hauser, Mather, Muehlner, Silverberg, Thaddeus, Weiss, Wilkinson) COBE History (2) • 1976, Mission Definition Science Team selected by HQ (Nancy Boggess, Program Scientist); PI’s chosen • ~ 1979, decision to build COBE in-house at GSFC • 1982, approval to construct for flight • 1986, Challenger explosion, start COBE redesign for Delta launch • 1989, Nov. -
Hubble's Law and the Expanding Universe
COMMENTARY COMMENTARY Hubble’s Law and the expanding universe Neta A. Bahcall1 the expansion rate is constant in all direc- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 tions at any given time, this rate changes with time throughout the life of the uni- verse. When expressed as a function of cos- In one of the most famous classic papers presented the observational evidence for one H t in the annals of science, Edwin Hubble’s of science’s greatest discoveries—the expand- mic time, ( ), it is known as the Hubble 1929 PNAS article on the observed relation inguniverse.Hubbleshowedthatgalaxiesare Parameter. The expansion rate at the pres- between distance and recession velocity of receding away from us with a velocity that is ent time, Ho, is about 70 km/s/Mpc (where 1 Mpc = 106 parsec = 3.26 × 106 light-y). galaxies—the Hubble Law—unveiled the proportional to their distance from us: more The inverse of the Hubble Constant is the expanding universe and forever changed our distant galaxies recede faster than nearby gal- Hubble Time, tH = d/v = 1/H ; it reflects understanding of the cosmos. It inaugurated axies. Hubble’s classic graph of the observed o the time since a linear cosmic expansion has the field of observational cosmology that has velocity vs. distance for nearby galaxies is begun (extrapolating a linear Hubble Law uncovered an amazingly vast universe that presented in Fig. 1; this graph has become back to time t = 0); it is thus related to has been expanding and evolving for 14 bil- a scientific landmark that is regularly repro- the age of the Universe from the Big-Bang lion years and contains dark matter, dark duced in astronomy textbooks. -
The Reionization of Cosmic Hydrogen by the First Galaxies Abstract 1
David Goodstein’s Cosmology Book The Reionization of Cosmic Hydrogen by the First Galaxies Abraham Loeb Department of Astronomy, Harvard University, 60 Garden St., Cambridge MA, 02138 Abstract Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 meter in diameter, and NASA’s successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. -
Galaxies at High Redshift Mauro Giavalisco
eaa.iop.org DOI: 10.1888/0333750888/1669 Galaxies at High Redshift Mauro Giavalisco From Encyclopedia of Astronomy & Astrophysics P. Murdin © IOP Publishing Ltd 2006 ISBN: 0333750888 Institute of Physics Publishing Bristol and Philadelphia Downloaded on Thu Mar 02 23:08:45 GMT 2006 [131.215.103.76] Terms and Conditions Galaxies at High Redshift E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Galaxies at High Redshift that is progressively higher for objects that are separated in space by larger distances. If the recession velocity between Galaxies at high REDSHIFT are very distant galaxies and, two objects is small compared with the speed of light, since light propagates through space at a finite speed of its value is directly proportional to the distance between approximately 300 000 km s−1, they appear to an observer them, namely v = H d on the Earth as they were in a very remote past, when r 0 the light departed them, carrying information on their H properties at that time. Observations of objects with very where the constant of proportionality 0 is called the high redshifts play a central role in cosmology because ‘HUBBLE CONSTANT’. For larger recession velocities this they provide insight into the epochs and the mechanisms relation is replaced by a more general one calculated from the theory of general relativity. In each cases, the value of GALAXY FORMATION, if one can reach redshifts that are high H enough to correspond to the cosmic epochs when galaxies of 0 provides the recession velocity of a pair of galaxies were forming their first populations of stars and began to separated by unitary distance, and hence sets the rate of shine light throughout space. -
The Anthropic Principle and Multiple Universe Hypotheses Oren Kreps
The Anthropic Principle and Multiple Universe Hypotheses Oren Kreps Contents Abstract ........................................................................................................................................... 1 Introduction ..................................................................................................................................... 1 Section 1: The Fine-Tuning Argument and the Anthropic Principle .............................................. 3 The Improbability of a Life-Sustaining Universe ....................................................................... 3 Does God Explain Fine-Tuning? ................................................................................................ 4 The Anthropic Principle .............................................................................................................. 7 The Multiverse Premise ............................................................................................................ 10 Three Classes of Coincidence ................................................................................................... 13 Can The Existence of Sapient Life Justify the Multiverse? ...................................................... 16 How unlikely is fine-tuning? .................................................................................................... 17 Section 2: Multiverse Theories ..................................................................................................... 18 Many universes or all possible -
Year 1 Cosmology Results from the Dark Energy Survey
Year 1 Cosmology Results from the Dark Energy Survey Elisabeth Krause on behalf of the Dark Energy Survey collaboration TeVPA 2017, Columbus OH Our Simple Universe On large scales, the Universe can be modeled with remarkably few parameters age of the Universe geometry of space density of atoms density of matter amplitude of fluctuations scale dependence of fluctuations [of course, details often not quite as simple] Our Puzzling Universe Ordinary Matter “Dark Energy” accelerates the expansion 5% dominates the total energy density smoothly distributed 25% acceleration first measured by SN 1998 “Dark Matter” 70% Our Puzzling Universe Ordinary Matter “Dark Energy” accelerates the expansion 5% dominates the total energy density smoothly distributed 25% acceleration first measured by SN 1998 “Dark Matter” next frontier: understand cosmological constant Λ: w ≡P/ϱ=-1? 70% magnitude of Λ very surprising dynamic dark energy varying in time and space, w(a)? breakdown of GR? Theoretical Alternatives to Dark Energy Many new DE/modified gravity theories developed over last decades Most can be categorized based on how they break GR: The only local, second-order gravitational field equations that can be derived from a four-dimensional action that is constructed solely from the metric tensor, and admitting Bianchi identities, are GR + Λ. Lovelock’s theorem (1969) [subject to viability conditions] Theoretical Alternatives to Dark Energy Many new DE/modified gravity theories developed over last decades Most can be categorized based on how they break GR: The only local, second-order gravitational field equations that can be derived from a four-dimensional action that is constructed solely from the metric tensor, and admitting Bianchi identities, are GR + Λ. -
Sandra Faber Receives $500,000 Gruber Cosmology Prize
Media Contact: A. Sarah Hreha +1 (203) 432-6231 [email protected] Online Newsroom: www.gruber.yale.edu/news-media SANDRA FABER RECEIVES $500,000 GRUBER COSMOLOGY PRIZE FOR CAREER ACHIEVEMENTS Sandra Faber May 17, 2017, New Haven, CT – The 2017 Gruber Foundation Cosmology Prize recognizes Sandra M. Faber for a body of work that has helped establish many of the foundational principles underlying the modern understanding of the universe on the largest scales. The citation praises Faber for “her groundbreaking studies of the structure, dynamics, and evolution of galaxies.” That work has led to the widespread acceptance of the need to study dark matter, to an appreciation of the inextricable relationship between the presence of dark matter and the formation of galaxies, and to the recognition that black holes reside at the heart of most large galaxies. She has also made significant contributions to the innovations in telescope technology that have revolutionized modern astronomy. Through these myriad achievements, the Gruber citation adds, Faber has “aided and inspired the work of astronomers and cosmologists worldwide.” Faber will receive the $500,000 award as well as a gold medal at a ceremony this fall. Less than a hundred years ago, astronomers were still debating whether our Milky Way Galaxy was the entirety of the universe or if other galaxies existed beyond our own. Today astronomers estimate the number of galaxies within the visible universe at somewhere between 200 billion and 2 trillion. For more than four decades Faber—now Professor Emerita at the University of California, Santa Cruz, and Astronomer Emerita of the University of California Observatories—has served as a pivotal figure in leading and guiding the exploration of this unimaginably vast virgin scientific territory. -
International Astrostatistics Association
<IAA> International Astrostatistics Association IAA Newsletter – December 2014 Articles on Astrostatistics December 2014 issue Significance magazine 88 pages: 28 on astrostatistics Significance Magazine is a British published magazine-journal for those who are in the statistics and research community. The magazine, which is typically about fifty pages in length, is published five to six times a year and comes with the membership dues of the American Statistical Association (ASA) and Royal Statistical Society (RSS). The International Statistical Institute (ISI) also makes the magazine available to its membership. Given that the ASA and RSS have a combined membership in excess of 30,000, the magazine is read, at least in part, by a relatively large number of people. The December issue, published on 2 December, is 88 pages, with a special 28 page section on astrostatistics included. The section consists of eleven articles.You may access the articles through the URL: http://onlinelibrary.wiley.com/doi/10.1111/sign.2014.11.issue-5/issuetoc 1 The cover portrays the subject of the initial article on meteor impacts. Each article comes with one or more nicely developed pictures. Tables and Graphics are also displayed. ARTICLES (pp 48-76) Life, the Universe, and Everything, Joseph M Hilbe (Arizona State Univ) 48 Will this century see a devastating meteor strike? Joseph M. Hilbe (Arizona State Univ) & Jamie Riggs (Northwestern Univ) 50 Impact records, Carlo Zapponi (Microsoft-UK) 54 The origin of structure, Benjamin Waldelt (Lagrange Institute, Paris) 56 Making sense of massive unknowns, Rafael de Souza (Eötvös Loránd Univ., Hungary) & Emille Ishida (Max Planck Institute, Garching, Ger) 59 Revealing the invisible, Jessi Cisewski (Carnegie Mellon Univ) 61 How many galaxies in the universe?, Vladimir Surdin (Moscow State Univ, Russia) 64 How do you weight a cluster of galaxies?, Madhura Killedar (Ludwig Maximilians Univ. -
Cosmic Microwave Background
1 29. Cosmic Microwave Background 29. Cosmic Microwave Background Revised August 2019 by D. Scott (U. of British Columbia) and G.F. Smoot (HKUST; Paris U.; UC Berkeley; LBNL). 29.1 Introduction The energy content in electromagnetic radiation from beyond our Galaxy is dominated by the cosmic microwave background (CMB), discovered in 1965 [1]. The spectrum of the CMB is well described by a blackbody function with T = 2.7255 K. This spectral form is a main supporting pillar of the hot Big Bang model for the Universe. The lack of any observed deviations from a 7 blackbody spectrum constrains physical processes over cosmic history at redshifts z ∼< 10 (see earlier versions of this review). Currently the key CMB observable is the angular variation in temperature (or intensity) corre- lations, and to a growing extent polarization [2–4]. Since the first detection of these anisotropies by the Cosmic Background Explorer (COBE) satellite [5], there has been intense activity to map the sky at increasing levels of sensitivity and angular resolution by ground-based and balloon-borne measurements. These were joined in 2003 by the first results from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP)[6], which were improved upon by analyses of data added every 2 years, culminating in the 9-year results [7]. In 2013 we had the first results [8] from the third generation CMB satellite, ESA’s Planck mission [9,10], which were enhanced by results from the 2015 Planck data release [11, 12], and then the final 2018 Planck data release [13, 14]. Additionally, CMB an- isotropies have been extended to smaller angular scales by ground-based experiments, particularly the Atacama Cosmology Telescope (ACT) [15] and the South Pole Telescope (SPT) [16]. -
Anniversary of the Einstein Equations
TH CELEBRATING THE 100 ANNIVERSARY OF THE MG14 RO ME 12-18 JULY 2015 EINSTEIN EQUATIONS FONO RECUENT DREVETLOEPMEENTNS IN TTHEHORET ICMAL ANAD EXRPERCIMEENTALL G EGNERRAL ROELATSIVSITYM, ASTRAOPHYNSICS,N AND REMLATIVEISTEIC FTIELID TNHEORG IES LOCAL ORGANIZING COMMITTEE INTERNATIONAL COORDINATING COMMITTEE Amati L., Angelantonj C., Barbiellini G., Bassan B., Battistelli E., Belinski V., Belli P., • ALBANIA : Hafizi M. • ESTONIA : Einasto J., Saar E. • FINLAND : Volovik G. • POLAND : Demianski M., Lewandowski J., Nurowski P., Benedetti R., Bernabei R., Bianchi M. (chair), Bianco C., Bini D., Buchert T., Burgio F., • ARGENTINA : Ghezzi, C.R., Mirabel F., Romero G.E. • FRANCE : Brillet A., Buchert T., Chardonnet P., Coullet P., Sokolowski L. Capozziello S., Chakrabarti S., Chardonnet P., Dall’Agata G., De Angelis A., De Bernardis P., • ARMENIA : Aharonian F., Harutyunian H., Sahakyan N. de Freitas Pacheco J.A., Deruelle N., Iliopoulos J., Mignard F. • PORTUGAL : Costa M., Moniz P., Pizarro de Sande e Lemos J., Della Valle M., Di Virgilio A., Fiorini E., Frasca S., Fré P., Frontera F., Giavalisco M., • AUSTRALIA : Ju L., Lun A., Manchester D., Melatos A., • GEORGIA : Lavrelashvili G. Silva L.O. • ROMANIA : Visinescu M. Giommi P., Gionti G., Ingrosso G., Jantzen R., Jetzer P., Lee H.W., Lerda A., Liberati S., Quinn P., Scott S.M., Steele J.D. • GERMANY : Biermann P., Blumlein J., Di Piazza A., Fritzsch • RUSSIA : Aksenov A., Arkhangelskaja I., Bisnovatyi Kogan Longo R., Mandolesi N., Marmo G., Masi S., Menotti P., Morselli A., Pelster A., • AUSTRIA : Aichelburg P.C., Schindler S. H., Genzel R., Gilmozzi R., Hehl F., Keitel C., Kiefer C., G., Blinnikov S., Chechetikin V.M., Cherepaschuk A.M., Piacentini F., Pian E., Quevedo H., Riccioni F., Rosati R., Scarpetta E.V., • BELARUS : Kilin S., Minkevich A.V.