A Brief History of Cosmology
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International Comet Quarterly
International Comet Quarterly Links International Comet Quarterly ICQ: Recommended (and condemned) sources for stellar magnitudes Cometary Science Center Comet magnitudes Below is a list that observers may use to evaluate whether the source(s) that they are Central Bureau for Astro. Tel. contemplating using for visual or V stellar magnitudes are recommended or not. Unfortunately, many errors have been found over the years in the both the individual variable-star charts of Minor Planet Center the AAVSO (ICQ code AC) and the AAVSO Variable Star Atlas (code AA); those variable-star EPS/Harvard charts were designed for the purpose of tracking the relative variation in brightness of individual variable stars, and they frequently are not adequately aligned with the proper magnitude scale. The new Hipparcos/Tycho catalogues have had new codes implemented (see below). New additions (and changes in categories) will be made to the following list as new information reaches the ICQ. MAGNITUDE-REFERENCE KEY Second-draft recommendation list, 1997 Dec. 1. Updated 2007 April 20 and 2017 Oct. 4. NOTE: For visual magnitude estimation of comets, NEVER USE SOURCES for which the available star magnitudes are only brighter than the comet! For example, the SAO Star Catalog is very poor for magnitudes fainter than 9.0, and should NEVER be used on comets fainter than mag 9.5. The Tycho catalogue should not be used for comets fainter than mag 10.5. (Even CCD photometrists should be wary of using bright stars for very faint comets; it is always best to use comparison stars within a few magnitudes of the comet when doing CCD photometry.) NOTE: It is highly recommended that users of variable-star charts also specify (in descriptive notes to accompany the tabulated data) the specific chart(s) used for each observation; this information will be published in the ICQ. -
Demystifying Special Relativity; the K-Factor Angel Darlene Harb
Demystifying Special Relativity; the K-Factor Angel Darlene Harb University of Texas at San Antonio, TX, U.S.A. ABSTRACT This paper targets upper-level high school students and incoming college freshmen who have been less exposed to Special Relativity (SR). The goal is to spark interest and eliminate any feelings of intimidation one might have about a topic brought forth by world genius Albert Einstein. For this purpose, we will introduce some ideas revolving around SR. Additionally, by deriving the relationship between the k-factor and relative velocity, we hope that students come to an appreciation for the impact of basic mathematical skills and the way these can be applied to quite complex models. Advanced readers can directly jump ahead to the section discussing the k-factor. keywords : relative velocity, world lines, space-time 1 Introduction 1.1 A Morsel of History Throughout time, scientists have searched for ’just the right’ model comprised of laws, assumptions and theories that could explain our physical world. One example of a leading physical law is: All matter in the universe is subject to the same forces. It is important to note, this principle is agreeable to scientists, not because it is empirically true, but because this law makes for a good model of nature. Consequently, this law unifies areas like mechanics, electricity and optics traditionally taught separate from each other. Sir Isaac Newton (1643-1727) contributed to this principle with his ’three laws of motion.’ They were so mathematically elegant, that the Newtonian model dominated the scientific mind for nearly two centuries. -
A Study of John Leslie's Infinite Minds, a Philosophical Cosmology
Document généré le 1 oct. 2021 09:18 Laval théologique et philosophique Infinite Minds, Determinism & Evil A Study of John Leslie’s Infinite Minds, A Philosophical Cosmology Leslie Armour La question de Dieu Volume 58, numéro 3, octobre 2002 URI : https://id.erudit.org/iderudit/000634ar DOI : https://doi.org/10.7202/000634ar Aller au sommaire du numéro Éditeur(s) Faculté de philosophie, Université Laval Faculté de théologie et de sciences religieuses, Université Laval ISSN 0023-9054 (imprimé) 1703-8804 (numérique) Découvrir la revue Citer cette note Armour, L. (2002). Infinite Minds, Determinism & Evil: A Study of John Leslie’s Infinite Minds, A Philosophical Cosmology. Laval théologique et philosophique, 58(3), 597–603. https://doi.org/10.7202/000634ar Tous droits réservés © Laval théologique et philosophique, Université Laval, Ce document est protégé par la loi sur le droit d’auteur. L’utilisation des 2002 services d’Érudit (y compris la reproduction) est assujettie à sa politique d’utilisation que vous pouvez consulter en ligne. https://apropos.erudit.org/fr/usagers/politique-dutilisation/ Cet article est diffusé et préservé par Érudit. Érudit est un consortium interuniversitaire sans but lucratif composé de l’Université de Montréal, l’Université Laval et l’Université du Québec à Montréal. Il a pour mission la promotion et la valorisation de la recherche. https://www.erudit.org/fr/ Laval théologique et philosophique, 58, 3 (octobre 2002) : 597-603 ◆ note critique INFINITE MINDS, DETERMINISM & EVIL A STUDY OF JOHN LESLIE’S INFINITE MINDS, A PHILOSOPHICAL COSMOLOGY * Leslie Armour The Dominican College of Philosophy and Theology Ottawa ohn Leslie’s Infinite Minds is a refreshingly daring book. -
Science and Religion in the Face of the Environmental Crisis
Roger S. Gottlieb, ed., The Oxford Handbook of Religion and Ecology. New York and Oxford: Oxford University Press, 2006. Pages 376-397. CHAPTER 17 .................................................................................................. SCIENCE AND RELIGION IN THE FACE OF THE ENVIRONMENTAL CRISIS ..................................................................................................... HOLMES ROLSTON III BOTH science and religion are challenged by the environmental crisis, both to reevaluate the natural world and to reevaluate their dialogue with each other. Both are thrown into researching fundamental theory and practice in the face of an upheaval unprecedented in human history, indeed in planetary history. Life on Earth is in jeopardy owing to the behavior of one species, the only species that is either scientific or religious, the only species claiming privilege as the "wise spe- cies," Homo sapiens. Nature and the human relation to nature must be evaluated within cultures, classically by their religions, currently also by the sciences so eminent in Western culture. Ample numbers of theologians and ethicists have become persuaded that religion needs to pay more attention to ecology, and many ecologists recognize religious dimensions to caring for nature and to addressing the ecological crisis. Somewhat ironically, just when humans, with their increasing industry and technology, seemed further and further from nature, having more knowledge about natural processes and more power to manage them, just when humans were more and more rebuilding their environments, thinking perhaps to escape nature, the natural world has emerged as a focus of concern. Nature remains the milieu of 376 SCIENCE AND RELIGION 377 culture—so both science and religion have discovered. In a currently popular vocabulary, humans need to get themselves "naturalized." Using another meta- phor, nature is the "womb" of culture, but a womb that humans never entirely leave. -
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. -
Physical Cosmology Physics 6010, Fall 2017 Lam Hui
Physical Cosmology Physics 6010, Fall 2017 Lam Hui My coordinates. Pupin 902. Phone: 854-7241. Email: [email protected]. URL: http://www.astro.columbia.edu/∼lhui. Teaching assistant. Xinyu Li. Email: [email protected] Office hours. Wednesday 2:30 { 3:30 pm, or by appointment. Class Meeting Time/Place. Wednesday, Friday 1 - 2:30 pm (Rabi Room), Mon- day 1 - 2 pm for the first 4 weeks (TBC). Prerequisites. No permission is required if you are an Astronomy or Physics graduate student { however, it will be assumed you have a background in sta- tistical mechanics, quantum mechanics and electromagnetism at the undergrad- uate level. Knowledge of general relativity is not required. If you are an undergraduate student, you must obtain explicit permission from me. Requirements. Problem sets. The last problem set will serve as a take-home final. Topics covered. Basics of hot big bang standard model. Newtonian cosmology. Geometry and general relativity. Thermal history of the universe. Primordial nucleosynthesis. Recombination. Microwave background. Dark matter and dark energy. Spatial statistics. Inflation and structure formation. Perturba- tion theory. Large scale structure. Non-linear clustering. Galaxy formation. Intergalactic medium. Gravitational lensing. Texts. The main text is Modern Cosmology, by Scott Dodelson, Academic Press, available at Book Culture on W. 112th Street. The website is http://www.bookculture.com. Other recommended references include: • Cosmology, S. Weinberg, Oxford University Press. • http://pancake.uchicago.edu/∼carroll/notes/grtiny.ps or http://pancake.uchicago.edu/∼carroll/notes/grtinypdf.pdf is a nice quick introduction to general relativity by Sean Carroll. • A First Course in General Relativity, B. -
Towards a Theory of Gravitational Radiation Or What Is a Gravitational Wave?
Recent LIGO announcement Gravitational radiation theory: summary Prehistory: 1916-1956 History: 1957-1962 Towards a theory of gravitational radiation or What is a gravitational wave? Paweł Nurowski Center for Theoretical Physics Polish Academy of Sciences King’s College London, 28 April 2016 1/48 Recent LIGO announcement Gravitational radiation theory: summary Prehistory: 1916-1956 History: 1957-1962 Plan 1 Recent LIGO announcement 2 Gravitational radiation theory: summary 3 Prehistory: 1916-1956 4 History: 1957-1962 2/48 Recent LIGO announcement Gravitational radiation theory: summary Prehistory: 1916-1956 History: 1957-1962 LIGO detection: Its relevance the first detection of gravitational waves the first detection of a black hole; of a binary black-hole; of a merging process of black holes creating a new one; Kerr black holes exist; black holes with up to 60 Solar masses exist; the most energetic process ever observed important test of Einstein’s General Theory of Relativity new window: a birth of gravitational wave astronomy 3/48 Recent LIGO announcement Gravitational radiation theory: summary Prehistory: 1916-1956 History: 1957-1962 LIGO detection: Its relevance the first detection of gravitational waves the first detection of a black hole; of a binary black-hole; of a merging process of black holes creating a new one; Kerr black holes exist; black holes with up to 60 Solar masses exist; the most energetic process ever observed important test of Einstein’s General Theory of Relativity new window: a birth of gravitational wave astronomy -
The Evolution of the IR Luminosity Function and Dust-Obscured Star Formation Over the Past 13 Billion Years
The Astrophysical Journal, 909:165 (15pp), 2021 March 10 https://doi.org/10.3847/1538-4357/abdb27 © 2021. The American Astronomical Society. All rights reserved. The Evolution of the IR Luminosity Function and Dust-obscured Star Formation over the Past 13 Billion Years J. A. Zavala1 , C. M. Casey1 , S. M. Manning1 , M. Aravena2 , M. Bethermin3 , K. I. Caputi4,5 , D. L. Clements6 , E. da Cunha7 , P. Drew1 , S. L. Finkelstein1 , S. Fujimoto5,8 , C. Hayward9 , J. Hodge10 , J. S. Kartaltepe11 , K. Knudsen12 , A. M. Koekemoer13 , A. S. Long14 , G. E. Magdis5,8,15,16 , A. W. S. Man17 , G. Popping18 , D. Sanders19 , N. Scoville20 , K. Sheth21 , J. Staguhn22,23 , S. Toft5,8 , E. Treister24 , J. D. Vieira25 , and M. S. Yun26 1 The University of Texas at Austin, 2515 Speedway Boulevard, Stop C1400, Austin, TX 78712, USA; [email protected] 2 Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile 3 Aix Marseille Univ, CNRS, LAM, Laboratoire d’Astrophysique de Marseille, Marseille, France 4 Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700AV Groningen, The Netherlands 5 Cosmic Dawn Center (DAWN), Denmark 6 Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2AZ, UK 7 International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia 8 Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, DK-2100 Copenhagen, Denmark 9 Center for Computational Astrophysics, Flatiron -
The High Redshift Universe: Galaxies and the Intergalactic Medium
The High Redshift Universe: Galaxies and the Intergalactic Medium Koki Kakiichi M¨unchen2016 The High Redshift Universe: Galaxies and the Intergalactic Medium Koki Kakiichi Dissertation an der Fakult¨atf¨urPhysik der Ludwig{Maximilians{Universit¨at M¨unchen vorgelegt von Koki Kakiichi aus Komono, Mie, Japan M¨unchen, den 15 Juni 2016 Erstgutachter: Prof. Dr. Simon White Zweitgutachter: Prof. Dr. Jochen Weller Tag der m¨undlichen Pr¨ufung:Juli 2016 Contents Summary xiii 1 Extragalactic Astrophysics and Cosmology 1 1.1 Prologue . 1 1.2 Briefly Story about Reionization . 3 1.3 Foundation of Observational Cosmology . 3 1.4 Hierarchical Structure Formation . 5 1.5 Cosmological probes . 8 1.5.1 H0 measurement and the extragalactic distance scale . 8 1.5.2 Cosmic Microwave Background (CMB) . 10 1.5.3 Large-Scale Structure: galaxy surveys and Lyα forests . 11 1.6 Astrophysics of Galaxies and the IGM . 13 1.6.1 Physical processes in galaxies . 14 1.6.2 Physical processes in the IGM . 17 1.6.3 Radiation Hydrodynamics of Galaxies and the IGM . 20 1.7 Bridging theory and observations . 23 1.8 Observations of the High-Redshift Universe . 23 1.8.1 General demographics of galaxies . 23 1.8.2 Lyman-break galaxies, Lyα emitters, Lyα emitting galaxies . 26 1.8.3 Luminosity functions of LBGs and LAEs . 26 1.8.4 Lyα emission and absorption in LBGs: the physical state of high-z star forming galaxies . 27 1.8.5 Clustering properties of LBGs and LAEs: host dark matter haloes and galaxy environment . 30 1.8.6 Circum-/intergalactic gas environment of LBGs and LAEs . -
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]. -
9. the Cosmic Microwave Background
A5682: Introduction to Cosmology Course Notes 9. The Cosmic Microwave Background Reading: Chapter 8, sections 8.0-8.3. (We will cover 8.4 and 8.5 later.) “Re”combination After Big Bang Nucleosynthesis, the universe was still much too hot for the formation of neutral atoms. As expansion continued, the background radiation photons redshifted and the temperature dropped. Naively, one would expect p + e− → H when kT ∼ 13.6eV. Just as with deuterium synthesis, however, the high value of nγ/nb implies that the exponential tail of the photon distribution can dissociate hydrogen atoms. Less naively, we expect p + e− → H when kT ∼ 13.6eV/(− ln η) ∼ 0.65eV, corresponding to (1 + z) ≈ 2700. A more accurate version of this argument given in the textbook (section 9.3) yields a predicted redshift of (1 + z) ≈ 1370 for hydrogen formation. In practice, there are several complicating factors, e.g., any recombination direct to the ground state produces a photon that can immediately ionize another neutral atom unless the photon survives long enough to be redshifted below 13.6 eV. A proper, somewhat tricky calculation of cosmic recombination shows that there is a fairly rapid transition from a free electron fraction xe ≈ 1 to xe ≈ 0 at z ≈ 1100, with most of the transition occuring over a redshift range ∆z ≈ 80. In the laboratory, or in regions ionized by hot stars or quasars or shocks, the process p + e− → H is usually referred to as “recombination.” In the early universe, the protons and electrons were never in the form of hydrogen to begin with, so this process should arguably be called “combination” rather than “recombination.” But “combination” sounds rather silly, so “recombination” is still the standard term for this tran- sition. -
The Astronomicalsociety Ofedinburgh
The AstronomicalSociety ofEdinburgh Journal 40 - December 1999 Harry Ford's modified Scotch Mount From the President - Alan Ellis 2 Cheap Astrophotography - a Variation on the Theme - Harry Ford 3 Scottish Astronomy Weekend - Dave Gavine 4 Leonids 1999 - Lorna McCalman 6 Other Observations - Dave Gavine 7 Popular Astronomy Class 7 Special Section on the Solar Eclipse of August 11 1999 8 Including "TheGreatHungarianEclipse" by GrahamYoung, plus reports from GerryTaylor, DaveGavine, MauriceFrank and GrahamRule James Melvill sees a great Comet in 1577 - Dave Gavine 13 Book Review - "The Young Astronomer" by Harry Ford 14 Scottish Astronomers' Group - Graham Rule 14 Published by the Astronomical Society of Edinburgh, City Observatory, Calton Hill, Edinburgh for circulation to members. Editor: Dr Dave Gavine, 29 Coillesdene Crescent, Edinburgh From the President Welcome to Edition 40 of the Society’s Journal. We have to thank Dave Gavine for editing this edition - and the other 39! Unfortunately, Dave has great difficulty in getting members to contribute articles so please consider writing about your astronomical interests whatever they might be - from reviews of books you have enjoyed to observations you have made. We have had quite a good year what with the eclipse and the Leonids - although the weather could have been a little more helpful for both these events. Charlie Gleed and Jim Douglas have continued to work on the Earlyburn site and we hope to start using it in the evenings soon - weather permitting. Recently the Observatory has featured in a BBC Scotland TV series in which Brian Kelly (formerly Dundee’s City Astronomer) may be seen sitting on the roof of the Playfair Building in a pink inflatable plastic arm-chair talking about aspects of astronomy.