The Expanding Universe: an Introduction Lecture at the WE Heraeus Summer School “Astronomy from Four Perspectives”, Heidelberg
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Summary As Preparation for the Final Exam
UUnnddeerrsstatannddiinngg ththee UUnniivveerrssee Summary Lecture Volker Beckmann Joint Center for Astrophysics, University of Maryland, Baltimore County & NASA Goddard Space Flight Center, Astrophysics Science Division UMBC, December 12, 2006 OOvveerrvviieeww ● What did we learn? ● Dark night sky ● distances in the Universe ● Hubble relation ● Curved space ● Newton vs. Einstein : General Relativity ● metrics solving the EFE: Minkowski and Robertson-Walker metric ● Solving the Einstein Field Equation for an expanding/contracting Universe: the Friedmann equation Graphic: ESA / V. Beckmann OOvveerrvviieeww ● Friedmann equation ● Fluid equation ● Acceleration equation ● Equation of state ● Evolution in a single/multiple component Universe ● Cosmic microwave background ● Nucleosynthesis ● Inflation Graphic: ESA / V. Beckmann Graphic by Michael C. Wang (UCSD) The velocity- distance relation for galaxies found by Edwin Hubble. Graphic: Edwin Hubble (1929) Expansion in a steady state Universe Expansion in a non-steady-state Universe The effect of curvature The equivalent principle: You cannot distinguish whether you are in an accelerated system or in a gravitational field NNeewwtotonn vvss.. EEiinnssteteiinn Newton: - mass tells gravity how to exert a force, force tells mass how to accelerate (F = m a) Einstein: - mass-energy (E=mc²) tells space time how to curve, curved space-time tells mass-energy how to move (John Wheeler) The effect of curvature A glimpse at EinsteinThe effect’s field of equationcurvature Left side (describes the action -
Abstract Generalized Natural Inflation and The
ABSTRACT Title of dissertation: GENERALIZED NATURAL INFLATION AND THE QUEST FOR COSMIC SYMMETRY BREAKING PATTERS Simon Riquelme Doctor of Philosophy, 2018 Dissertation directed by: Professor Zackaria Chacko Department of Physics We present a two-field model that generalizes Natural Inflation, in which the inflaton is the pseudo-Goldstone boson of an approximate symmetry that is spon- taneously broken, and the radial mode is dynamical. Within this model, which we designate as \Generalized Natural Inflation”, we analyze how the dynamics fundamentally depends on the mass of the radial mode and determine the size of the non-Gaussianities arising from such a scenario. We also motivate ongoing research within the coset construction formalism, that aims to clarify how the spontaneous symmetry breaking pattern of spacetime, gauge, and internal symmetries may allow us to get a deeper understanding, and an actual algebraic classification in the spirit of the so-called \zoology of con- densed matter", of different possible \cosmic states", some of which may be quite relevant for model-independent statements about different phases in the evolution of our universe. The outcome of these investigations will be reported elsewhere. GENERALIZED NATURAL INFLATION AND THE QUEST FOR COSMIC SYMMETRY BREAKING PATTERNS by Simon Riquelme Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2018 Advisory Committee: Professor Zackaria Chacko, Chair/Advisor Professor Richard Wentworth, Dean's Representative Professor Theodore Jacobson Professor Rabinda Mohapatra Professor Raman Sundrum A mis padres, Kattya y Luis. ii Acknowledgments It is a pleasure to acknowledge my adviser, Dr. -
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. -
Degree in Mathematics
Degree in Mathematics Title: Singularities and qualitative study in LQC Author: Llibert Aresté Saló Advisor: Jaume Amorós Torrent, Jaume Haro Cases Department: Departament de Matemàtiques Academic year: 2017 Universitat Polit`ecnicade Catalunya Facultat de Matem`atiquesi Estad´ıstica Degree in Mathematics Bachelor's Degree Thesis Singularities and qualitative study in LQC Llibert Arest´eSal´o Supervised by: Jaume Amor´osTorrent, Jaume Haro Cases January, 2017 Singularities and qualitative study in LQC Abstract We will perform a detailed analysis of singularities in Einstein Cosmology and in LQC (Loop Quantum Cosmology). We will obtain explicit analytical expressions for the energy density and the Hubble constant for a given set of possible Equations of State. We will also consider the case when the background is driven by a single scalar field, obtaining analytical expressions for the corresponding potential. And, in a given particular case, we will perform a qualitative study of the orbits in the associated phase space of the scalar field. Keywords Quantum cosmology, Equation of State, cosmic singularity, scalar field. 1 Contents 1 Introduction 3 2 Einstein Cosmology 5 2.1 Friedmann Equations . .5 2.2 Analysis of the singularities . .7 2.3 Reconstruction method . .9 2.4 Dynamics for the linear case . 12 3 Loop Quantum Cosmology 16 3.1 Modified Friedmann equations . 16 3.2 Analysis of the singularities . 18 3.3 Reconstruction method . 21 3.4 Dynamics for the linear case . 23 4 Conclusions 32 2 Singularities and qualitative study in LQC 1. Introduction In 1915, Albert Einstein published his field equations of General Relativity [1], giving birth to a new conception of gravity, which would now be understood as the curvature of space-time. -
The Age of the Universe, the Hubble Constant, the Accelerated Expansion and the Hubble Effect
The age of the universe, the Hubble constant, the accelerated expansion and the Hubble effect Domingos Soares∗ Departamento de F´ısica,ICEx, UFMG | C.P. 702 30123-970, Belo Horizonte | Brazil October 25, 2018 Abstract The idea of an accelerating universe comes almost simultaneously with the determination of Hubble's constant by one of the Hubble Space Tele- scope Key Projects. The age of the universe dilemma is probably the link between these two issues. In an appendix, I claim that \Hubble's law" might yet to be investigated for its ultimate cause, and suggest the \Hubble effect” as the searched candidate. 1 The age dilemma The age of the universe is calculated by two different ways. Firstly, a lower limit is given by the age of the presumably oldest objects in the Milky Way, e.g., globular clusters. Their ages are calculated with the aid of stellar evolu- tion models which yield 14 Gyr and 10% uncertainty. These are fairly confident figures since the basics of stellar evolution are quite solid. Secondly, a cosmo- logical age based on the Standard Cosmology Model derived from the Theory of General Relativity. The three basic models of relativistic cosmology are given by the Friedmann's solutions of Einstein's field equations. The models are char- acterized by a decelerated expansion from a spatial singularity at cosmic time t = 0, and whose magnitude is quantified by the density parameter Ω◦, the present ratio of the mass density in the universe to the so-called critical mass arXiv:0908.1864v8 [physics.gen-ph] 28 Jul 2015 density. -
Pre-Big Bang, Space-Time Structure, Asymptotic Universe
EPJ Web of Conferences 71, 0 0 063 (2 014 ) DOI: 10.1051/epjconf/20147100063 C Owned by the authors, published by EDP Sciences, 2014 Pre-Big Bang, space-time structure, asymptotic Universe Spinorial space-time and a new approach to Friedmann-like equations Luis Gonzalez-Mestres1,a 1Megatrend Cosmology Laboratory, Megatrend University, Belgrade and Paris Goce Delceva 8, 11070 Novi Beograd, Serbia Abstract. Planck and other recent data in Cosmology and Particle Physics can open the way to controversial analyses concerning the early Universe and its possible ultimate origin. Alternatives to standard cosmology include pre-Big Bang approaches, new space- time geometries and new ultimate constituents of matter. Basic issues related to a possible new cosmology along these lines clearly deserve further exploration. The Planck collab- oration reports an age of the Universe t close to 13.8 Gyr and a present ratio H between relative speeds and distances at cosmic scale around 67.3 km/s/Mpc. The product of these two measured quantities is then slightly below 1 (about 0.95), while it can be exactly 1 in the absence of matter and cosmological constant in patterns based on the spinorial space- time we have considered in previous papers. In this description of space-time we first suggested in 1996-97, the cosmic time t is given by the modulus of a SU(2) spinor and the Lundmark-Lemaître-Hubble (LLH) expansion law turns out to be of purely geometric origin previous to any introduction of standard matter and relativity. Such a fundamen- tal geometry, inspired by the role of half-integer spin in Particle Physics, may reflect an equilibrium between the dynamics of the ultimate constituents of matter and the deep structure of space and time. -
The Ups and Downs of Baryon Oscillations
The Ups and Downs of Baryon Oscillations Eric V. Linder Physics Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720 ABSTRACT Baryon acoustic oscillations, measured through the patterned distribution of galaxies or other baryon tracing objects on very large (∼> 100 Mpc) scales, offer a possible geometric probe of cosmological distances. Pluses and minuses in this approach’s leverage for understanding dark energy are discussed, as are systematic uncertainties requiring further investigation. Conclusions are that 1) BAO offer promise of a new avenue to distance measurements and further study is warranted, 2) the measurements will need to attain ∼ 1% accuracy (requiring a 10000 square degree spectroscopic survey) for their dark energy leverage to match that from supernovae, but do give complementary information at 2% accuracy. Because of the ties to the matter dominated era, BAO is not a replacement probe of dark energy, but a valuable complement. 1. Introduction This paper provides a pedagogical introduction to baryon acoustic oscillations (BAO), accessible to readers not necessarily familiar with details of large scale structure in the universe. In addition, it summarizes some of the current issues – plus and minus – with the use of BAO as a cosmological probe of the nature of dark energy. For more quantitative, arXiv:astro-ph/0507308v2 17 Jan 2006 technical discussions of these issues, see White (2005). The same year as the detection of the cosmic microwave background, the photon bath remnant from the hot, early universe, Sakharov (1965) predicted the presence of acoustic oscillations in a coupled baryonic matter distribution. In his case, baryons were coupled to cold electrons rather than hot photons; Peebles & Yu (1970) and Sunyaev & Zel’dovich (1970) pioneered the correct, hot case. -
AST4220: Cosmology I
AST4220: Cosmology I Øystein Elgarøy 2 Contents 1 Cosmological models 1 1.1 Special relativity: space and time as a unity . 1 1.2 Curvedspacetime......................... 3 1.3 Curved spaces: the surface of a sphere . 4 1.4 The Robertson-Walker line element . 6 1.5 Redshifts and cosmological distances . 9 1.5.1 Thecosmicredshift . 9 1.5.2 Properdistance. 11 1.5.3 The luminosity distance . 13 1.5.4 The angular diameter distance . 14 1.5.5 The comoving coordinate r ............... 15 1.6 TheFriedmannequations . 15 1.6.1 Timetomemorize! . 20 1.7 Equationsofstate ........................ 21 1.7.1 Dust: non-relativistic matter . 21 1.7.2 Radiation: relativistic matter . 22 1.8 The evolution of the energy density . 22 1.9 The cosmological constant . 24 1.10 Some classic cosmological models . 26 1.10.1 Spatially flat, dust- or radiation-only models . 27 1.10.2 Spatially flat, empty universe with a cosmological con- stant............................ 29 1.10.3 Open and closed dust models with no cosmological constant.......................... 31 1.10.4 Models with more than one component . 34 1.10.5 Models with matter and radiation . 35 1.10.6 TheflatΛCDMmodel. 37 1.10.7 Models with matter, curvature and a cosmological con- stant............................ 40 1.11Horizons.............................. 42 1.11.1 Theeventhorizon . 44 1.11.2 Theparticlehorizon . 45 1.11.3 Examples ......................... 46 I II CONTENTS 1.12 The Steady State model . 48 1.13 Some observable quantities and how to calculate them . 50 1.14 Closingcomments . 52 1.15Exercises ............................. 53 2 The early, hot universe 61 2.1 Radiation temperature in the early universe . -
Hubble's Diagram and Cosmic Expansion
Hubble’s diagram and cosmic expansion Robert P. Kirshner* Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 Contributed by Robert P. Kirshner, October 21, 2003 Edwin Hubble’s classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy’s distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble’s Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble’s distances have a large systematic error, Hubble’s velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today’s burgeoning field of cosmology. he publication of Edwin Hub- ble’s 1929 article ‘‘A relation between distance and radial T velocity among extra-galactic nebulae’’ marked a turning point in un- derstanding the universe. In this brief report, Hubble laid out the evidence for one of the great discoveries in 20th cen- tury science: the expanding universe. Hubble showed that galaxies recede from us in all directions and more dis- tant ones recede more rapidly in pro- portion to their distance. His graph of velocity against distance (Fig. 1) is the original Hubble diagram; the equation that describes the linear fit, velocity ϭ ϫ Ho distance, is Hubble’s Law; the slope of that line is the Hubble con- ͞ stant, Ho; and 1 Ho is the Hubble time. -
Observational Cosmology - 30H Course 218.163.109.230 Et Al
Observational cosmology - 30h course 218.163.109.230 et al. (2004–2014) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Thu, 31 Oct 2013 03:42:03 UTC Contents Articles Observational cosmology 1 Observations: expansion, nucleosynthesis, CMB 5 Redshift 5 Hubble's law 19 Metric expansion of space 29 Big Bang nucleosynthesis 41 Cosmic microwave background 47 Hot big bang model 58 Friedmann equations 58 Friedmann–Lemaître–Robertson–Walker metric 62 Distance measures (cosmology) 68 Observations: up to 10 Gpc/h 71 Observable universe 71 Structure formation 82 Galaxy formation and evolution 88 Quasar 93 Active galactic nucleus 99 Galaxy filament 106 Phenomenological model: LambdaCDM + MOND 111 Lambda-CDM model 111 Inflation (cosmology) 116 Modified Newtonian dynamics 129 Towards a physical model 137 Shape of the universe 137 Inhomogeneous cosmology 143 Back-reaction 144 References Article Sources and Contributors 145 Image Sources, Licenses and Contributors 148 Article Licenses License 150 Observational cosmology 1 Observational cosmology Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Early observations The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity. -
Time in Cosmology
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Philsci-Archive Time in Cosmology Craig Callender∗ C. D. McCoyy 21 August 2017 Readers familiar with the workhorse of cosmology, the hot big bang model, may think that cosmology raises little of interest about time. As cosmological models are just relativistic spacetimes, time is under- stood just as it is in relativity theory, and all cosmology adds is a few bells and whistles such as inflation and the big bang and no more. The aim of this chapter is to show that this opinion is not completely right...and may well be dead wrong. In our survey, we show how the hot big bang model invites deep questions about the nature of time, how inflationary cosmology has led to interesting new perspectives on time, and how cosmological speculation continues to entertain dramatically different models of time altogether. Together these issues indicate that the philosopher interested in the nature of time would do well to know a little about modern cosmology. Different claims about time have long been at the heart of cosmology. Ancient creation myths disagree over whether time is finite or infinite, linear or circular. This speculation led to Kant complaining in his famous antinomies that metaphysical reasoning about the nature of time leads to a “euthanasia of reason”. But neither Kant’s worry nor cosmology becoming a modern science succeeded in ending the speculation. Einstein’s first model of the universe portrays a temporally infinite universe, where space is edgeless and its material contents unchanging. -
Ex Latere Christi Ex Latere Christi
EX LATEREWoman: Her Nature & CHRISTIVirtues THE PONTIFICAL NORTH AMERICAN COLLEGE WINTER 2020 - ISSUE 1 1 11 First Feature 32 Second Feature 34 Third Feature 36 Fourth Feature EX LATERE CHRISTI EX LATERE CHRISTI Rector, Publisher (ex-officio) VERY Rev. PETER C. HARMAN, STD Academic Dean, Executive Editor (ex-officio) Rev. JOHN P. CUSH, STD Editor-in-Chief Rev. RANDY DEJESUS SOTO, STD Managing Editor MR. AleXANdeR J. WYVIll, PHL Student Editor MR. AARON J. KellY, PHL Assistant Student Editor MR. THOMAS O’DONNell, BA www.pnac.org TAble OF CONTENTS A WORD OF INTRODUCTION FROM THE EXECUTIVE EDITOR 7 Rev. John P. Cush, STD EX LATERE CHRISTI 10 Msgr. William Millea, STL, JCD SAlve, AEDES MATER! 11 Rev. Randy DeJesus Soto, STD WOMAN: HER NATURE & VIRTUES 13 Sr. Mary Angelica Neenan, O.P., STD AS THE PERSON GOES, SO GOES THE WHOLE WORLD 39 Aaron J. Kelly, PHL BEING IN THE RIGHT 51 Alexander J. Wyvill, PHL HANS URS VON BALTHASAR AND DIALOGICAL PHILOSOPHY 91 Rev. Walter R. Oxley, STD JESUS CHRIST: WORD, PREACHER AND LORD 101 Rev. Randy DeJesus Soto, STD HOMILY FOR THE MASS OF THE PASSION OF ST. JOHN THE BAPTIST 131 Rev. Adam Y. Park, STL LOGOS, CREATION AND SCIENCE 135 Rev. Joseph Laracy, STD HOLINESS 163 Msgr. James McNamara, M.Div., MS, PA CATHERINE PICKSTOCK’S EUCHARISTIC THEOLOGY 167 Rev. John P. Cush, STD CONTRIBUTORS 211 6 Rev. JOHN P. CUSH, STD A WORD OF INTRODUCTION FROM THE EXecUTIve EDITOR As the college’s academic dean, it is a joy to present to you Ex Latere Christi, the first academic journal published by the faculty, alumni, and friends of the Pontifical North American College.