Tests and Problems of the Standard Model in Cosmology
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Is the Universe Expanding?: an Historical and Philosophical Perspective for Cosmologists Starting Anew
Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 6-1996 Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew David A. Vlosak Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Cosmology, Relativity, and Gravity Commons Recommended Citation Vlosak, David A., "Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew" (1996). Master's Theses. 3474. https://scholarworks.wmich.edu/masters_theses/3474 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. IS THEUN IVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STAR TING ANEW by David A Vlasak A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements forthe Degree of Master of Arts Department of Philosophy Western Michigan University Kalamazoo, Michigan June 1996 IS THE UNIVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STARTING ANEW David A Vlasak, M.A. Western Michigan University, 1996 This study addresses the problem of how scientists ought to go about resolving the current crisis in big bang cosmology. Although this problem can be addressed by scientists themselves at the level of their own practice, this study addresses it at the meta level by using the resources offered by philosophy of science. There are two ways to resolve the current crisis. -
Olbers' Paradox
Astro 101 Fall 2013 Lecture 12 Cosmology T. Howard Cosmology = study of the Universe as a whole • ? What is it like overall? • ? What is its history? How old is it? • ? What is its future? • ? How do we find these things out from what we can observe? • In 1996, researchers at the Space Telescope Science Institute used the Hubble to make a very long exposure of a patch of seemingly empty sky. Q: What did they find? A: Galaxies “as far as The eye can see …” (nearly everything in this photo is a galaxy!) 40 hour exposure What do we know already (about the Universe) ? • Galaxies in groups; clusters; superclusters • Nearby universe has “filament” and void type of structure • More distant objects are receding from us (light is redshifted) • Hubble’s Law: V = H0 x D (Hubble's Law) Structure in the Universe What is the largest kind of structure in the universe? The ~100-Mpc filaments, shells and voids? On larger scales, things look more uniform. 600 Mpc Olbers’ Paradox • Assume the universe is homogeneous, isotropic, infinte, and static • Then: Why don’t we see light everywhere? Why is the night sky (mostly) dark? Olbers’ Paradox (cont’d.) • We believe the universe is homogeneous and isotropic • So, either it isn’t infinite OR it isn’t static • “Big Bang” theory – universe started expanding a finite time ago Given what we know of structure in the universe, assume: The Cosmological Principle On the largest scales, the universe is roughly homogeneous (same at all places) and isotropic (same in all directions). Laws of physics are everywhere the same. -
Probing the Dark Flow Signal in WMAP 9Yr and PLANCK CMB Maps
Probing the Dark Flow signal in WMAP 9yr and PLANCK CMB Maps. Fernando Atrio-Barandela. Departamento de F´ısica Fundamental. Universidad de Salamanca. eml: [email protected] In collaboration with: H. Ebeling, D. Fixsen, A. Kashlinsky, D. Kocevski. Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 1 Summary. Introduction: The CMB dipole. Measuring Peculiar Velocities. Results with WMAP. Results with PLANCK (Planck Collaboration). Results with PLANCK (Our Analysis). Cosmological Implications and Conclusions. Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 2 Introduction: The CMB dipole. Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 3 The Cosmic Microwave Background. Monopole T=2.73K Dipole T=3mK Octupole O=33 K Planck Nominal Map at 353GHz Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 4 The CMB dipole. If density perturbations are adiabatic, generated during inflation, then the low order • multipoles verify: ℓ(ℓ + 1)C = const 2C = 12C = 12 1000(µK)2 D 70µ 1mK ℓ ⇒ 1 3 ∗ ⇒ ∼ ≪ Then, the dipole CAN NOT BE PRIMORDIAL. It is a Doppler effect due to the local motion of the Local Group with velocity 600km/s in the direction of l = 2700, b = 300. ∼ Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 5 The convergence of the CMB dipole. COMA VIRGO CENTAURUS HYDRA PERSEUS (Left) CMB dipole measured by COBE. (Right) Large Scale Structure and gas distribution in the Local Universe. What are the scales that contribute to the 600km/s peculiar velocity of the LG? ∼ Ibericos 2015 Aranjuez, March 30th - April 1st, 2015. 6 Bulk Flows. The zero order moment of the velocity field is the mean peculiar velocity of a sphere of radius R or bulk flow 1 V 2(R) = P (k)W 2(kR)dk P (k) = δ(k) 2. -
Facts and Ideas in Modern Cosmology
FACTS AND IDEAS IN MODERN COSMOLOGY Yu. V. Baryshev(1,2) F. Sylos Labini(3,4) M. Montuori(4,5) L. Pietronero(4) 1 (1) Astronomical Institute of St. Petersburg University, St. Petersburg 198904, Russia (2) Scientific-Educational Union ”Earth & Universe”, St. Petersburg, Russia (3) Dipartimento di Fisica, Universit`adi Bologna, Italy (4) Dipartimento di Fisica, Universit`adi Roma ” La Sapienza” P.le A. Moro 2, I-00185 Roma, Italy. (5) Dipartimento di Fisica, Universit`adi Cosenza, Italy Accepted for publication in Vistas In astronomy Vol.38 Part.4, 1994 Abstract A review of the principles of observational testing of cosmological theories is given with a special emphasis on the distinction between observational facts and theoretical hypotheses. A classification of modern cosmological theories and possible observational tests for these theories is presented. The main rival cosmological models are analyzed from the point of view of observational testing of their initial hypothesis. A comparison of modern observational data with theoretical predictions is presented. In particular we discuss in detail the validity of the two basic assumptions of modern cosmology that are the Cosmological Principle and the Expanding Space Paradigm. It is found that classical paradigms need to be reanalyzed and that it is necessary to develop crucial cosmological tests to discriminate alternative theories. arXiv:astro-ph/9503074v1 20 Mar 1995 1 INTRODUCTION Cosmology as a part of physics is an experimental science. For this reason all reasonable relations in cosmology must have an experimental confirmation. The fast growth of observational data in the last two decades now has made possible the comparison between observable quantities and theoretical predictions. -
Analysis and Measurement of Horn Antennas for CMB Experiments
Analysis and Measurement of Horn Antennas for CMB Experiments Ian Mc Auley (M.Sc. B.Sc.) A thesis submitted for the Degree of Doctor of Philosophy Maynooth University Department of Experimental Physics, Maynooth University, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland. October 2015 Head of Department Professor J.A. Murphy Research Supervisor Professor J.A. Murphy Abstract In this thesis the author's work on the computational modelling and the experimental measurement of millimetre and sub-millimetre wave horn antennas for Cosmic Microwave Background (CMB) experiments is presented. This computational work particularly concerns the analysis of the multimode channels of the High Frequency Instrument (HFI) of the European Space Agency (ESA) Planck satellite using mode matching techniques to model their farfield beam patterns. To undertake this analysis the existing in-house software was upgraded to address issues associated with the stability of the simulations and to introduce additional functionality through the application of Single Value Decomposition in order to recover the true hybrid eigenfields for complex corrugated waveguide and horn structures. The farfield beam patterns of the two highest frequency channels of HFI (857 GHz and 545 GHz) were computed at a large number of spot frequencies across their operational bands in order to extract the broadband beams. The attributes of the multimode nature of these channels are discussed including the number of propagating modes as a function of frequency. A detailed analysis of the possible effects of manufacturing tolerances of the long corrugated triple horn structures on the farfield beam patterns of the 857 GHz horn antennas is described in the context of the higher than expected sidelobe levels detected in some of the 857 GHz channels during flight. -
La Radiación Del Fondo Cósmico De Microondas Abstracts
Simposio Internacional: La radiación del Fondo Cósmico de Microondas: mensajera de los orígenes del universo International Symposium: CMB Radiation: Messenger of the Origins of Our Universe Madrid, 6 de noviembre de 2014 Madrid, November 6, 2014 I The seeds of structure: A view of the Cosmic Microwave Background, Joseph Silk The shape of the universe as seen by Planck, Enrique Martínez-González Deciphering the beginnings of the universe with CMB polarization, Matías Zaldarriaga 30 years of Cosmic Microwave Background experiments in Tenerife: From temperature to polarization maps, Rafael Rebolo Cosmology from Planck: Do we need a new Physics?, Nazzareno Mandolesi FUNDACIÓN RAMÓN ARECES Simposio Internacional: La radiación del Fondo Cósmico de Microondas: mensajera de los orígenes del universo International Symposium: CMB Radiation: Messenger of the Origins of Our Universe Madrid, 6 de noviembre de 2014 Madrid, November 6, 2014 The seeds of structure: A view of the Cosmic Microwave Background, Joseph Silk One of our greatest challenges is understanding the origin of the structure of the universe.I will describe how the fossil radiation from the beginning of the universe, the cosmic microwave background, has provided a window for probing the initial conditions from which structure evolved. Infinitesimal variations in temperature on the sky, first discovered in 1992, provide the fossil fluctuations that seeded the formation of the galaxies. The cosmic microwave background radiation has now been mapped with ground-based, balloon-borne and satellite telescopes. These provide the basis for our current ``precision cosmology'' in which the universe not only contains Dark Matter but also ``DarkEnergy'', which has accelerated its expansion exponentially in the last 4 billion years. -
Friedmann Equation (1.39) for a Radiation Dominated Universe Will Thus Be (From Ada ∝ Dt)
Lecture 2 The quest for the origin of the elements The quest for the origins of the elements, C. Bertulani, RISP, 2016 1 Reading2.1 - material Geometry of the Universe 2-dimensional analogy: Surface of a sphere. The surface is finite, but has no edge. For a creature living on the sphere, having no sense of the third dimension, there is no center (on the sphere). All points are equal. Any point on the surface can be defined as the center of a coordinate system. But, how can a 2-D creature investigate the geometry of the sphere? Answer: Measure curvature of its space. Flat surface (zero curvature, k = 0) Closed surface Open surface (posiDve curvature, k = 1) (negave curvature, k = -1) The quest for the origins of the elements, C. Bertulani, RISP, 2016 2 ReadingGeometry material of the Universe These are the three possible geometries of the Universe: closed, open and flat, corresponding to a density parameter Ωm = ρ/ρcrit which is greater than, less than or equal to 1. The relation to the curvature parameter is given by Eq. (1.58). The closed universe is of finite size. Traveling far enough in one direction will lead back to one's starting point. The open and flat universes are infinite and traveling in a constant direction will never lead to the same point. The quest for the origins of the elements, C. Bertulani, RISP, 2016 3 2.2 - Static Universe 2 2 The static Universe requires a = a0 = constant and thus d a/dt = da/dt = 0. From Eq. -
The Triple-Quasar Is an Optical Image of Milkyway, Andromeda and Triangulum Galaxies – Implies Expansion in the Direction of Dark Flow
The Triple-quasar is an optical image of Milkyway, Andromeda and Triangulum galaxies – implies expansion in the direction of Dark Flow Jose P Koshy [email protected] Abstract: Based on the concept that light follows a circular path of radius 2.5 billion light-years, here I show that the triple-quasar LBQS 1429-008 is the 10.5 billion years old image of 'Milkyway, Andromeda and Triangulum' galaxies. From this, the position of our galaxy at two different times can be ascertained, and the direction of expansion of the universe can be estimated. The 'surprise finding' is that the direction thus obtained is in agreement with the direction of so- called 'Dark flow', implying the possibility that the expansion is due to actual motion of bodies, and hence LCDM model is wrong. 1. Introduction: The standard cosmological model (LCDM) visualizes metric expansion of the universe. In such a model, the motion of galaxy clusters with respect to the cosmic microwave background should be randomly distributed in all directions. However, using WMAP data, Alexander Kashlinsky1 et al have found evidence for a possible non-random component in the motion of galaxy clusters; this is referred to as 'dark flow'. This implies the possibility that expansion is due to actual 'physical motion' of bodies. An alternate model, explained in my previous papers, visualizes expansion as a consequence of 'actual motion' of galaxy-clusters. Also, the model visualizes that light follows a 'circular path', and so the returning rays can create past images of bodies that have moved out. So, based on that model, it becomes possible to ascertain 'the direction' in which the universe in our region expands. -
Astrophysics Notre Dame’S Partnership in the Large Binocular Telescope
NOTRE DAME ASTROPHYSICS NOTRE DAME’S PARTNERSHIP IN THE LARGE BINOCULAR TELESCOPE The Large Binocular Telescope (LBT) stands on carbon and oxygen are created, and the LBT will Mt. Graham in Arizona, at 10,700 feet above sea support our quest for understanding. level, and next to the 1.8-m Vatican Advanced Technology Telescope. The unique facility is Telescopes not only look at distant objects, actually two 8.4-m telescopes that act in tandem but also act as time machines. Because light to produce images unlike any seen before. The may travel for billions of years before being LBT has the equivalent collecting power of a captured by the LBT’s mirrors, the images 12-m and the resolution of a 22-m telescope, far reveal the Universe as it was long ago. One of better than any other telescope today. It is the the big mysteries uncovered by the Hubble forerunner of the next generation of ultra-large Space Telescope program is the existence of telescopes. fully formed galaxies in the early universe, much earlier than physicists predicted. Their formation The LBT has extraordinary capabilities. will be a key research program for the LBT and Its design allows it to directly observe distant Origins Institute faculty Dinshaw Balsara and stars systems and to actually see planets in the Christopher Howk, who aim to understand the systems. Its ability to measure very precise atomic dynamics that govern the formation of galaxies spectra even enables researchers to determine the and with them the beginnings of life. chemical makeup of the planets’ atmospheres. -
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. -
Planck 2015 Results. XII. Full Focal Plane Simulations Planck Collaboration: P
Astronomy & Astrophysics manuscript no. A14˙Simulations c ESO 2016 August 13, 2016 Planck 2015 results. XII. Full Focal Plane simulations Planck Collaboration: P. A. R. Ade87, N. Aghanim60, M. Arnaud75, M. Ashdown71;5, J. Aumont60, C. Baccigalupi86, A. J. Banday95;9, R. B. Barreiro66, J. G. Bartlett1;68, N. Bartolo31;67, E. Battaner97;98, K. Benabed61;94, A. Benoˆıt58, A. Benoit-Levy´ 25;61;94, J.-P. Bernard95;9, M. Bersanelli34;49, P. Bielewicz84;9;86, J. J. Bock68;11, A. Bonaldi69, L. Bonavera66, J. R. Bond8, J. Borrilly14;90, F. R. Bouchet61;89, F. Boulanger60, M. Bucher1, C. Burigana48;32;50, R. C. Butler48, E. Calabrese92, J.-F. Cardoso76;1;61, G. Castex1, A. Catalano77;74, A. Challinor63;71;12, A. Chamballu75;16;60, H. C. Chiang28;6, P. R. Christensen85;37, D. L. Clements56, S. Colombi61;94, L. P. L. Colombo24;68, C. Combet77, F. Couchot73, A. Coulais74, B. P. Crill68;11, A. Curto66;5;71, F. Cuttaia48, L. Danese86, R. D. Davies69, R. J. Davis69, P. de Bernardis33, A. de Rosa48, G. de Zotti45;86, J. Delabrouille1, J.-M. Delouis61;94, F.-X. Desert´ 54, C. Dickinson69, J. M. Diego66, K. Dolag96;81, H. Dole60;59, S. Donzelli49, O. Dore´68;11, M. Douspis60, A. Ducout61;56, X. Dupac39, G. Efstathiou63, F. Elsner25;61;94, T. A. Enßlin81, H. K. Eriksen64, J. Fergusson12, F. Finelli48;50, O. Forni95;9, M. Frailis47, A. A. Fraisse28, E. Franceschi48, A. Frejsel85, S. Galeotta47, S. Galli70, K. Ganga1, T. Ghosh60, M. Giard95;9, Y. Giraud-Heraud´ 1, E. Gjerløw64, J. Gonzalez-Nuevo´ 20;66, K. -
Astronomy 422
Astronomy 422 Lecture 15: Expansion and Large Scale Structure of the Universe Key concepts: Hubble Flow Clusters and Large scale structure Gravitational Lensing Sunyaev-Zeldovich Effect Expansion and age of the Universe • Slipher (1914) found that most 'spiral nebulae' were redshifted. • Hubble (1929): "Spiral nebulae" are • other galaxies. – Measured distances with Cepheids – Found V=H0d (Hubble's Law) • V is called recessional velocity, but redshift due to stretching of photons as Universe expands. • V=H0D is natural result of uniform expansion of the universe, and also provides a powerful distance determination method. • However, total observed redshift is due to expansion of the universe plus a galaxy's motion through space (peculiar motion). – For example, the Milky Way and M31 approaching each other at 119 km/s. • Hubble Flow : apparent motion of galaxies due to expansion of space. v ~ cz • Cosmological redshift: stretching of photon wavelength due to expansion of space. Recall relativistic Doppler shift: Thus, as long as H0 constant For z<<1 (OK within z ~ 0.1) What is H0? Main uncertainty is distance, though also galaxy peculiar motions play a role. Measurements now indicate H0 = 70.4 ± 1.4 (km/sec)/Mpc. Sometimes you will see For example, v=15,000 km/s => D=210 Mpc = 150 h-1 Mpc. Hubble time The Hubble time, th, is the time since Big Bang assuming a constant H0. How long ago was all of space at a single point? Consider a galaxy now at distance d from us, with recessional velocity v. At time th ago it was at our location For H0 = 71 km/s/Mpc Large scale structure of the universe • Density fluctuations evolve into structures we observe (galaxies, clusters etc.) • On scales > galaxies we talk about Large Scale Structure (LSS): – groups, clusters, filaments, walls, voids, superclusters • To map and quantify the LSS (and to compare with theoretical predictions), we use redshift surveys.