DOCSLIB.ORG

The Multiverse • Mariusz P

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

The The Multiverse • Mariusz P. Dąbrowski, Ana Alonso-Serrano • Mariusz P. and Thomas Naumann The Multiverse Edited by Mariusz P. Dąbrowski, Ana Alonso-Serrano and Thomas Naumann Printed Edition of the Special Issue Published in Universe www.mdpi.com/journal/universe The Multiverse The Multiverse Special Issue Editors Mariusz P. D¸abrowski Ana Alonso-Serrano Thomas Naumann MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin Special Issue Editors Mariusz P. Da¸browski Ana Alonso-Serrano Thomas Naumann Institute of Physics, Max-Planck Institute for Deutsches Elektronen-Synchrotron University of Szczecin Gravitational Physics, DESY Poland Albert Einstein Institute Germany Germany Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal Universe (ISSN 2218-1997) (available at: https://www.mdpi.com/journal/universe/special issues/ the multiverse). For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. Journal Name Year, Article Number, Page Range. ISBN 978-3-03928-867-0 (Hbk) ISBN 978-3-03928-868-7 (PDF) c 2020 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND. Contents About the Special Issue Editors ..................................... vii Ana Alonso-Serrano, Mariusz P. D¸abrowski and Thomas Naumann Post-Editorial of “The Multiverse” Special Volume Reprinted from: Universe 2020, 6, 17, doi:10.3390/universe6010017 .................. 1 Michael Heller Multiverse—Too Much or Not Enough? Reprinted from: Universe 2019, 5, 113, doi:10.3390/universe5050113 ................. 5 Ana Alonso-Serrano and Gil Jannes Conceptual Challenges on the Road to the Multiverse Reprinted from: Universe 2019, 5, 212, doi:10.3390/universe5100212 ................. 15 Mariusz P. D¸abrowski Anthropic Selection of Physical Constants, Quantum Entanglement, and the Multiverse Falsifiability Reprinted from: Universe 2019, 5, 172, doi:10.3390/universe5070172 ................. 37 Michael Douglas The String Theory Landscape Reprinted from: Universe 2019, 5, 176, doi:10.3390/universe5070176 ................. 59 Salvador J. Robles-Perez Time Reversal Symmetry in Cosmology and the Creation of a Universe–Antiuniverse Pair Reprinted from: Universe 2019, 5, 150, doi:10.3390/universe5060150 ................. 75 Eckhard Rebhan Possible Origins and Properties of an Expanding, Dark Energy Providing Dark Multiverse Reprinted from: Universe 2019, 5, 178, doi:10.3390/universe5080178 ................. 87 McCullen Sandora Multiverse Predictions for Habitability: The Number of Stars and Their Properties Reprinted from: Universe 2019, 5, 149, doi:10.3390/universe5060149 .................109 McCullen Sandora Multiverse Predictions for Habitability: Number of Potentially Habitable Planets Reprinted from: Universe 2019, 5, 157, doi:10.3390/universe5060157 .................135 McCullen Sandora Multiverse Predictions for Habitability: Fraction of Planets that Develop Life Reprinted from: Universe 2019, 5, 171, doi:10.3390/universe5070171 .................169 McCullen Sandora Multiverse Predictions for Habitability: Fraction of Life That Develops Intelligence Reprinted from: Universe 2019, 5, 175, doi:10.3390/universe5070175 .................199 v About the Special Issue Editors Mariusz P. D¸abrowski is a theoretical physicist specializing in cosmology, nuclear physics, and particle physics. He is Full Professor at the Institute of Physics, University of Szczecin, and Head of the Szczecin Cosmology Group, which he created. He received his Ph.D. in theoretical physics at the Institute of Theoretical Physics, University of Wrocław, Poland, in 1989 and was awarded the title of Full Professor by the President of Poland in 2012. He has authored about 100 research papers in cosmology and related fields and has led many grants, including a recent project (2013–2018) dealing with the variability of fundamental constants in physics and cosmology funded by the Polish National Science Centre. His main research accomplishments are the proposal of some new inhomogeneous models of the universe (Stephani–Da¸browski models), the exploration of exotic singularities in the universe, and discovering a new type of barotropic index w-singularity. Most recently he suggested a novel test for astronomical measurement of the variability of the speed of light in the universe, formulated cyclic models of the multiverse, including calculations of inter-universal entanglement entropy, and worked on some aspects of generalized and extended uncertainty principles in quantum mechanics with consequences for black holes and the universe. Prof. Da¸browski is also active in the dissemination of results in astronomy, cosmology, and nuclear and particle physics to the general public, in collaboration with the Copernicus Center for Interdisciplinary Studies, Krakow,´ Poland, among others. Ana Alonso Serrano is a junior researcher at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Germany. She is a theoretical physicist working on the interplay between general relativity and quantum mechanics. She developed her thesis research at The Spanish National Research Council (CSIC) in Spain, obtaining her Ph.D. at the Complutense University of Madrid in 2015. Since then, she had several postdoctoral positions at Victoria University of Wellington (New Zealand), Charles University of Prague (Czech Republic) and Max Planck Insitute for Gravitational Physics (Germany). Her work has addressed several aspects of the multiverse, wormholes, quantum cosmology, and the study of singularities, black holes information paradox, quantum field theory in curved spaces and phenomenology of quantum gravity among others. She is also very involved in scientific outreach activities by giving talks, publishing articles, organizing workshops, and being part of the Berlin Soapbox Science team. Thomas Naumann Prof. Naumann finished his Diploma of physics at the Technical University of Dresden in 1975. He then started to study strongly interacting elementary particles at the Institute of High Energy Physics in Zeuthen near Berlin and finished his Ph.D. at the Humboldt University of Berlin in 1980. In 1987, Prof Naumann joined the H1 experiment at the electro-proto collider HERA at the Deutsches Elektronen-Synchroton DESY where he became a senior scientist in 1992 and worked on the precision measurement of the proton structure function and the coupling constant of the strong interaction. In 2005, he was appointed Honorary Professor at the University of Leipzig. Prof. Naumann joined the ATLAS experiment at the Large Hadron Collider LHC at CERN in 2006. Since 2012 he has led the Particle Physics Group of the DESY site in Zeuthen and represents Germany in the International Particle Physics Outreach Group IPPOG. vii universe Editorial Post-Editorial of “The Multiverse” Special Volume Ana Alonso-Serrano 1, Mariusz P. Da¸browski 2,3,4,* and Thomas Naumann 5 1 Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Mühlenberg 1, D-14476 Golm, Germany; [email protected] 2 Institute of Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin, Poland 3 National Centre for Nuclear Research, Andrzeja Sołtana 7, 05-400 Otwock, Poland 4 Copernicus Center for Interdisciplinary Studies, Szczepa´nska 1/5, 31-011 Kraków, Poland 5 Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738 Zeuthen, Germany; [email protected] * Correspondence: [email protected] Received: 6 January 2020; Accepted: 14 January 2020; Published: 20 January 2020 Abstract: A succesful series of papers devoted to various aspects of an idea of the Multiverse have been gathered together and presented to the readers. In this post-editorial we briefly challenge the content referring to the main issues dealt with by the Authors. We hope that this will inspire other investigators for designing future tests which could make this very notion of the Multiverse falsifiable. Keywords: philosophy of multiverse; categories of multiverses; different physics universes; superstring multiverse; dark multiverse; multiverse entanglement; universe-antiuniverse pair creation; multiverse habitability: stars, planets, life, consciousness; falsifiability of multiverses Although the idea of the Multiverse as a collection of possible universes has entered the area of physics long time ago, it is right now when it is taking viability and providing alternatives to confront the current cosmological conundrums. While one may consider the studies related to the concept of the Multiverse as a new revolution that can change the current paradigm in cosmology, in fact, it can rather be understood as the next step in the Copernican transit, where our habitat has gradually lost relevance as unique, special, and also tiny as compared to early science ages thought. Nowadays, the notion of the multiverse emerges naturally from some developments in cosmology and particle physics as a consequence
Recommended publications
  • Lomonosov, the Discovery of Venus's Atmosphere, and Eighteenth Century Transits of Venus

    Lomonosov, the Discovery of Venus's Atmosphere, and Eighteenth Century Transits of Venus

    Journal of Astronomical History and Heritage, 15(1), 3-14 (2012). LOMONOSOV, THE DISCOVERY OF VENUS'S ATMOSPHERE, AND EIGHTEENTH CENTURY TRANSITS OF VENUS Jay M. Pasachoff Hopkins Observatory, Williams College, Williamstown, Mass. 01267, USA. E-mail: [email protected] and William Sheehan 2105 SE 6th Avenue, Willmar, Minnesota 56201, USA. E-mail: [email protected] Abstract: The discovery of Venus's atmosphere has been widely attributed to the Russian academician M.V. Lomonosov from his observations of the 1761 transit of Venus from St. Petersburg. Other observers at the time also made observations that have been ascribed to the effects of the atmosphere of Venus. Though Venus does have an atmosphere one hundred times denser than the Earth’s and refracts sunlight so as to produce an ‘aureole’ around the planet’s disk when it is ingressing and egressing the solar limb, many eighteenth century observers also upheld the doctrine of cosmic pluralism: believing that the planets were inhabited, they had a preconceived bias for believing that the other planets must have atmospheres. A careful re-examination of several of the most important accounts of eighteenth century observers and comparisons with the observations of the nineteenth century and 2004 transits shows that Lomonosov inferred the existence of Venus’s atmosphere from observations related to the ‘black drop’, which has nothing to do with the atmosphere of Venus. Several observers of the eighteenth-century transits, includ- ing Chappe d’Auteroche, Bergman, and Wargentin in 1761 and Wales, Dymond, and Rittenhouse in 1769, may have made bona fide observations of the aureole produced by the atmosphere of Venus.
  • Charles Darwin: a Companion

    Charles Darwin: a Companion

    CHARLES DARWIN: A COMPANION Charles Darwin aged 59. Reproduction of a photograph by Julia Margaret Cameron, original 13 x 10 inches, taken at Dumbola Lodge, Freshwater, Isle of Wight in July 1869. The original print is signed and authenticated by Mrs Cameron and also signed by Darwin. It bears Colnaghi's blind embossed registration. [page 3] CHARLES DARWIN A Companion by R. B. FREEMAN Department of Zoology University College London DAWSON [page 4] First published in 1978 © R. B. Freeman 1978 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the permission of the publisher: Wm Dawson & Sons Ltd, Cannon House Folkestone, Kent, England Archon Books, The Shoe String Press, Inc 995 Sherman Avenue, Hamden, Connecticut 06514 USA British Library Cataloguing in Publication Data Freeman, Richard Broke. Charles Darwin. 1. Darwin, Charles – Dictionaries, indexes, etc. 575′. 0092′4 QH31. D2 ISBN 0–7129–0901–X Archon ISBN 0–208–01739–9 LC 78–40928 Filmset in 11/12 pt Bembo Printed and bound in Great Britain by W & J Mackay Limited, Chatham [page 5] CONTENTS List of Illustrations 6 Introduction 7 Acknowledgements 10 Abbreviations 11 Text 17–309 [page 6] LIST OF ILLUSTRATIONS Charles Darwin aged 59 Frontispiece From a photograph by Julia Margaret Cameron Skeleton Pedigree of Charles Robert Darwin 66 Pedigree to show Charles Robert Darwin's Relationship to his Wife Emma 67 Wedgwood Pedigree of Robert Darwin's Children and Grandchildren 68 Arms and Crest of Robert Waring Darwin 69 Research Notes on Insectivorous Plants 1860 90 Charles Darwin's Full Signature 91 [page 7] INTRODUCTION THIS Companion is about Charles Darwin the man: it is not about evolution by natural selection, nor is it about any other of his theoretical or experimental work.
  • No. 40. the System of Lunar Craters, Quadrant Ii Alice P

    No. 40. the System of Lunar Craters, Quadrant Ii Alice P

    NO. 40. THE SYSTEM OF LUNAR CRATERS, QUADRANT II by D. W. G. ARTHUR, ALICE P. AGNIERAY, RUTH A. HORVATH ,tl l C.A. WOOD AND C. R. CHAPMAN \_9 (_ /_) March 14, 1964 ABSTRACT The designation, diameter, position, central-peak information, and state of completeness arc listed for each discernible crater in the second lunar quadrant with a diameter exceeding 3.5 km. The catalog contains more than 2,000 items and is illustrated by a map in 11 sections. his Communication is the second part of The However, since we also have suppressed many Greek System of Lunar Craters, which is a catalog in letters used by these authorities, there was need for four parts of all craters recognizable with reasonable some care in the incorporation of new letters to certainty on photographs and having diameters avoid confusion. Accordingly, the Greek letters greater than 3.5 kilometers. Thus it is a continua- added by us are always different from those that tion of Comm. LPL No. 30 of September 1963. The have been suppressed. Observers who wish may use format is the same except for some minor changes the omitted symbols of Blagg and Miiller without to improve clarity and legibility. The information in fear of ambiguity. the text of Comm. LPL No. 30 therefore applies to The photographic coverage of the second quad- this Communication also. rant is by no means uniform in quality, and certain Some of the minor changes mentioned above phases are not well represented. Thus for small cra- have been introduced because of the particular ters in certain longitudes there are no good determi- nature of the second lunar quadrant, most of which nations of the diameters, and our values are little is covered by the dark areas Mare Imbrium and better than rough estimates.
  • Glossary Glossary

    Glossary Glossary

    Glossary Glossary Albedo A measure of an object’s reflectivity. A pure white reflecting surface has an albedo of 1.0 (100%). A pitch-black, nonreflecting surface has an albedo of 0.0. The Moon is a fairly dark object with a combined albedo of 0.07 (reflecting 7% of the sunlight that falls upon it). The albedo range of the lunar maria is between 0.05 and 0.08. The brighter highlands have an albedo range from 0.09 to 0.15. Anorthosite Rocks rich in the mineral feldspar, making up much of the Moon’s bright highland regions. Aperture The diameter of a telescope’s objective lens or primary mirror. Apogee The point in the Moon’s orbit where it is furthest from the Earth. At apogee, the Moon can reach a maximum distance of 406,700 km from the Earth. Apollo The manned lunar program of the United States. Between July 1969 and December 1972, six Apollo missions landed on the Moon, allowing a total of 12 astronauts to explore its surface. Asteroid A minor planet. A large solid body of rock in orbit around the Sun. Banded crater A crater that displays dusky linear tracts on its inner walls and/or floor. 250 Basalt A dark, fine-grained volcanic rock, low in silicon, with a low viscosity. Basaltic material fills many of the Moon’s major basins, especially on the near side. Glossary Basin A very large circular impact structure (usually comprising multiple concentric rings) that usually displays some degree of flooding with lava. The largest and most conspicuous lava- flooded basins on the Moon are found on the near side, and most are filled to their outer edges with mare basalts.
  • The State of the Multiverse: the String Landscape, the Cosmological Constant, and the Arrow of Time

    The State of the Multiverse: the String Landscape, the Cosmological Constant, and the Arrow of Time

    The State of the Multiverse: The String Landscape, the Cosmological Constant, and the Arrow of Time Raphael Bousso Center for Theoretical Physics University of California, Berkeley Stephen Hawking: 70th Birthday Conference Cambridge, 6 January 2011 RB & Polchinski, hep-th/0004134; RB, arXiv:1112.3341 The Cosmological Constant Problem The Landscape of String Theory Cosmology: Eternal inflation and the Multiverse The Observed Arrow of Time The Arrow of Time in Monovacuous Theories A Landscape with Two Vacua A Landscape with Four Vacua The String Landscape Magnitude of contributions to the vacuum energy graviton (a) (b) I Vacuum fluctuations: SUSY cutoff: ! 10−64; Planck scale cutoff: ! 1 I Effective potentials for scalars: Electroweak symmetry breaking lowers Λ by approximately (200 GeV)4 ≈ 10−67. The cosmological constant problem −121 I Each known contribution is much larger than 10 (the observational upper bound on jΛj known for decades) I Different contributions can cancel against each other or against ΛEinstein. I But why would they do so to a precision better than 10−121? Why is the vacuum energy so small? 6= 0 Why is the energy of the vacuum so small, and why is it comparable to the matter density in the present era? Recent observations Supernovae/CMB/ Large Scale Structure: Λ ≈ 0:4 × 10−121 Recent observations Supernovae/CMB/ Large Scale Structure: Λ ≈ 0:4 × 10−121 6= 0 Why is the energy of the vacuum so small, and why is it comparable to the matter density in the present era? The Cosmological Constant Problem The Landscape of String Theory Cosmology: Eternal inflation and the Multiverse The Observed Arrow of Time The Arrow of Time in Monovacuous Theories A Landscape with Two Vacua A Landscape with Four Vacua The String Landscape Many ways to make empty space Topology and combinatorics RB & Polchinski (2000) I A six-dimensional manifold contains hundreds of topological cycles.
  • The Age of the Universe Transcript

    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.
  • Mathematical Statistics (Math 30) – Course Project for Spring 2011

    Mathematical Statistics (Math 30) – Course Project for Spring 2011

    Mathematical Statistics (Math 30) – Course Project for Spring 2011 Goals: To explore methods from class in a real life (historical) estimation setting To learn some basic statistical computational skills To explore a topic of interest via a short report on a selected paper The course project has been divided into 2 parts. Each part will account for 5% of your grade, because the project accounts for 10%. Part 1: German Tank Problem Due Date: April 8th Our Setting: The Purple (Amherst) and Gold (Williams) armies are at war. You are a highly ranked intelligence officer in the Purple army and you are given the job of estimating the number of tanks in the Gold army’s tank fleet. Luckily, the Gold army has decided to put sequential serial numbers on their tanks, so you can consider their tanks labeled as 1,2,3,…,N, and all you have to do is estimate N. Suppose you have access to a random sample of k serial numbers obtained by spies, found on abandoned/destroyed equipment, etc. Using your k observations, you need to estimate N. Note that we won’t deal with issues of sampling without replacement, so you can consider each observation as an independent observation from a discrete uniform distribution on 1 to N. The derivations below should lead you to consider several possible estimators of N, from which you will be picking one to propose as your estimate of N. Historical Setting: This was a real problem encountered by statisticians/intelligence in WWII. The Allies wanted to know how many tanks the Germans were producing per month (the procedure was used for things other than tanks too).
  • Is a Global Identity Possible? the Relevance of Big History to Self-Other Relations”, Refugee Watch, (13):36, 2010, Pp.53-77

    Is a Global Identity Possible? the Relevance of Big History to Self-Other Relations”, Refugee Watch, (13):36, 2010, Pp.53-77

    On The Possibility of a Global Political Community: The Enigma of ‘Small Local Differences’ within Humanity1 Heikki Patomäki Introduction Is anything like a global political community – and thereby ideals such as global democracy and justice – achievable? This is a key question not only for political theory but also for contemporary political practices. For instance, a call for global solidarity in the face of rapid global warming (UNDP 2007), which seems ever more urgent in 2017, assumes a shared planetary identity across the currently prevailing differences and divisions. It seems that there can be no solidarity without a common identity at some level of human being. Environmentalists maintain that all humans share an important thing in common, namely planet Earth and its sphere of life, to which we essentially belong. In contrast, many political realists believe that humans are essentially tribal beings, or at least will remain so in the foreseeable future. This belief may be grounded on anything from speculative philosophical accounts of the human nature to sociobiological theories 1 This paper has been in progress for a decade. I first wrote it in 2007 and presented it in a few conferences, workshops and the like, including the Calcutta Research Group Winter School in December 2007. That presentation led eventually to a limited-circulation publication “Is a Global Identity Possible? The Relevance of Big History to Self-Other Relations”, Refugee Watch, (13):36, 2010, pp.53-77. A couple of years later I used the last two sections of this paper in a revised form in “The Problems of Legitimation and Potential Conflicts in a World Political Community”, Cooperation & Conflict, (47):2, 2012, pp.239-59.
  • Hubble's Law and the Expanding Universe

    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.
  • Gravity Without Dark Matter

    Gravity Without Dark Matter

    Gravity Without Dark Matter John Moffat Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada 1/13/2005 Miami 2004 1 Contents n 1. Introduction n 2. Gravity theory n 3. Action and field equations n 4. Quantum gravity and group renormalization flow n 5. Modified Newtonian acceleration n and flat galaxy rotation curves n 6. Galaxy clusters and lensing n 7. Cosmology without dark matter n 8. Conclusions 1/13/2005 Miami 2004 2 1. Introduction n Can gravity theory explain galaxy dynamics and cosmology without dominant dark matter? n We need a gravity theory that generalizes GR. Such a generalization is nonsymmetric gravitational theory (NGT). n A simpler theory is metric-skew-tensor gravity (MSTG). n There is also the problem of the nature of Dark Energy that explains the accelerating Universe. n The gravity theory must be stable and contain GR in a consistent way. It must yield agreement with solar system tests and the binary pulsar PSR 1913+16. n The cosmology without dominant dark matter must agree with the latest WMAP and CMB data. 1/13/2005 Miami 2004 3 2. Gravity theory n A popular phenomenological model that replaces dark matter is MOND (Milgrom, Beckenstein, Sanders-McGough). This phenomenology fits the flat rotation curves of galaxies, but has no acceptable relativistic gravity theory (see, however, Beckenstein 2004). n The MSTG theory can explain flat rotation curves of galaxies and cosmology without dominant dark matter. n We need to incorporate quantum gravity in a renormalization group (RG) flow framework with effective running coupling “constants” and an effective action.
  • Anthropic Explanations in Cosmology

    Anthropic Explanations in Cosmology

    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PhilSci Archive 1 Jesús Mosterín ANTHROPIC EXPLANATIONS IN COSMOLOGY In the last century cosmology has ceased to be a dormant branch of speculative philosophy and has become a vibrant part of physics, constantly invigorated by new empirical inputs from a legion of new terrestrial and outer space detectors. Nevertheless cosmology continues to be relevant to our philosophical world view, and some conceptual and methodological issues arising in cosmology are in need of epistemological analysis. In particular, in the last decades extraordinary claims have been repeatedly voiced for an alleged new type of scientific reasoning and explanation, based on a so-called “anthropic principle”. “The anthropic principle is a remarkable device. It eschews the normal methods of science as they have been practiced for centuries, and instead elevates humanity's existence to the status of a principle of understanding” [Greenstein 1988, p. 47]. Steven Weinberg has taken it seriously at some stage, while many physicists and philosophers of science dismiss it out of hand. The whole issue deserves a detailed critical analysis. Let us begin with a historical survey. History of the anthropic principle After Herman Weyl’s remark of 1919 on the dimensionless numbers in physics, several eminent British physicists engaged in numerological or aprioristic speculations in the 1920's and 1930's (see Barrow 1990). Arthur Eddington (1923) calculated the number of protons and electrons in the universe (Eddington's number, N) and found it to be around 10 79 . He noticed the coincidence between N 1/2 and the ratio of the electromagnetic to gravitational 2 1/2 39 forces between a proton and an electron: e /Gm emp ≈ N ≈ 10 .
  • The Multiverse: Conjecture, Proof, and Science

    The Multiverse: Conjecture, Proof, and Science

    The multiverse: conjecture, proof, and science George Ellis Talk at Nicolai Fest Golm 2012 Does the Multiverse Really Exist ? Scientific American: July 2011 1 The idea The idea of a multiverse -- an ensemble of universes or of universe domains – has received increasing attention in cosmology - separate places [Vilenkin, Linde, Guth] - separate times [Smolin, cyclic universes] - the Everett quantum multi-universe: other branches of the wavefunction [Deutsch] - the cosmic landscape of string theory, imbedded in a chaotic cosmology [Susskind] - totally disjoint [Sciama, Tegmark] 2 Our Cosmic Habitat Martin Rees Rees explores the notion that our universe is just a part of a vast ''multiverse,'' or ensemble of universes, in which most of the other universes are lifeless. What we call the laws of nature would then be no more than local bylaws, imposed in the aftermath of our own Big Bang. In this scenario, our cosmic habitat would be a special, possibly unique universe where the prevailing laws of physics allowed life to emerge. 3 Scientific American May 2003 issue COSMOLOGY “Parallel Universes: Not just a staple of science fiction, other universes are a direct implication of cosmological observations” By Max Tegmark 4 Brian Greene: The Hidden Reality Parallel Universes and The Deep Laws of the Cosmos 5 Varieties of Multiverse Brian Greene (The Hidden Reality) advocates nine different types of multiverse: 1. Invisible parts of our universe 2. Chaotic inflation 3. Brane worlds 4. Cyclic universes 5. Landscape of string theory 6. Branches of the Quantum mechanics wave function 7. Holographic projections 8. Computer simulations 9. All that can exist must exist – “grandest of all multiverses” They can’t all be true! – they conflict with each other.