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Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
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OCR for page R1
Cosmology: A Research Briefing
Cosmology: A Research Briefing
Panel on Cosmology
Board on Physics and Astronomy
Commission on Physical Sciences, Mathematics, and Applications
National Research Council
National Academy Press
Washington, D.C.
1995
OCR for page R2
Cosmology: A Research Briefing
NOTICE: The project that is the subject of this report was approvedby the Governing Board of the National Research Council, whose membersare drawn from the councils of the National Academy of Sciences,the National Academy of Engineering, and the Institute of Medicine.The members of the panel responsible for the report were chosen fortheir special competences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors accordingto procedures approved by a Report Review Committee consisting ofmembers of the National Academy of Sciences, the National Academyof Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuatingsociety of distinguished scholars engaged in scientific and engineeringresearch, dedicated to the furtherance of science and technologyand to their use for the general welfare. Upon the authority of thecharter granted to it by Congress in 1863, the Academy has a mandatethat requires it to advise the federal government on scientific andtechnical matters. Dr. Bruce Alberts is president of the NationalAcademy of Sciences.
The National Academy of Engineering was established in 1964, underthe charter of the National Academy of Sciences, as a parallel organizationof outstanding engineers. It is autonomous in its administrationand in the selection of its members, sharing with the National Academyof Sciences the responsibility for advising the federal government.The National Academy of Engineering also sponsors engineering programsaimed at meeting national needs, encourages education and research,and recognizes the superior achievements of engineers. Dr. HaroldLiebowitz is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the NationalAcademy of Sciences to secure the services of eminent members ofappropriate professions in the examination of policy matters pertainingto the health of the public. The Institute acts under the responsibilitygiven to the National Academy of Sciences by its congressional charterto be an advisor to the federal government and, upon its own initiative,to identify issues of medical care, research, and education. Dr.Kenneth I. Shine is president of the Institute of Medicine.
The National Research Council was established by the National Academyof Sciences in 1916 to associate the broad community of science andtechnology with the Academy's purposes of furthering knowledge andadvising the federal government. Functioning in accordance with generalpolicies determined by the Academy, the Council has become the principaloperating agency of both the National Academy of Sciences and theNational Academy of Engineering in providing services to the government,the public, and the scientific and engineering communities. The Councilis administered jointly by both Academies and the Institute of Medicine.Dr. Bruce Alberts and Dr. Harold Liebowitz are chairman and vicechairman, respectively, of the National Research Council.
This project was supported by the National Aeronautics and SpaceAdministration (NASA) under Grant No. NAGW-3304.
Front Cover: The anisotropy of the temperature of the cosmic microwave backgroundradiation, as mapped by the Differential Microwave Radiometer onNASA's Cosmic Background Explorer satellite. Red shades representhotter fluctuations, and blue and black shades represent cooler fluctuations.(Courtesy of the COBE team and NASA.)
Back Cover: Looking back in time with NASA's Hubble Space Telescope (HST). The HST's Wide-Field Planetary Camera (WFPC2) captured this image of galaxiesas they were billions of years ago. Many objects are irregular andill-formed compared to nearby galaxies, showing the evolution offorms of galaxies between the distant past and times closer to thepresent. The size of the image is 75 arc seconds, and the total exposuretime is 15 hours. (Courtesy of Edward Groth, Jerome Kristian, andmembers of the WFPC2 team.)
Additional copies of this report are available from:
Board on Physics and Astronomy
HA 562
National Research Council
2101 Constitution Avenue, NW
Washington, DC 20418
Copyright 1995 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
OCR for page R3
Cosmology: A Research Briefing
PANEL ON COSMOLOGY
MARC DAVIS,
University of California at Berkeley,
Chair
BLAS CABRERA,
Stanford University
SANDRA M. FABER,
University of California, Santa Cruz
MARGARET GELLER,
Harvard-Smithsonian Center for Astrophysics
JACQUELINE N. HEWITT,
Massachusetts Institute of Technology
RICHARD KRON,
Yerkes Observatory, University of Chicago
PHILIP M. LUBIN,
University of California, Santa Barbara
STEPHAN S. MEYER,
University of Chicago
JEREMIAH P. OSTRIKER,
Princeton University Observatory
DAVID N. SCHRAMM,
University of Chicago
DAVID WILKINSON,
Princeton University
DONALD C. SHAPERO, Director
ROBERT L. RIEMER, Senior Program Officer
OCR for page R4
Cosmology: A Research Briefing
BOARD ON PHYSICS AND ASTRONOMY
DAVID N. SCHRAMM,
University of Chicago,
Chair
ROBERT C. DYNES,
University of California, San Diego,
Vice Chair
LLOYD ARMSTRONG, JR.,
University of Southern California
DAVID H. AUSTON,
Rice University
DAVID E. BALDWIN,
Lawrence Livermore National Laboratory
PRAVEEN CHAUDHARI,
IBM T.J. Watson Research Center
FRANK DRAKE,
University of California, Santa Cruz
HANS FRAUENFELDER,
Los Alamos National Laboratory
JEROME I. FRIEDMAN,
Massachusetts Institute of Technology
MARGARET GELLER,
Harvard-Smithsonian Center for Astrophysics
MARTHA P. HAYNES,
Cornell University
WILLIAM KLEMPERER,
Harvard University
ALBERT NARATH,
Sandia National Laboratories
JOSEPH M. PROUD,
GTE Corporation (retired)
ROBERT C. RICHARDSON,
Cornell University
JOHANNA STACHEL,
State University of New York at Stony Brook
DAVID WILKINSON,
Princeton University
SIDNEY WOLFF,
National Optical Astronomy Observatories
DONALD C. SHAPERO, Director
ROBERT L. RIEMER, Associate Director
DANIEL F. MORGAN, Program Officer
NATASHA A. CASEY, Program Assistant
STEPHANIE Y. SMITH, Project Assistant
OCR for page R5
Cosmology: A Research Briefing
COMMISSION ON PHYSICAL SCIENCES, MATHEMATICS, AND APPLICATIONS
RICHARD N. ZARE,
Stanford University,
Chair
RICHARD S. NICHOLSON,
American Association for the Advancement of Science,
Vice Chair
STEPHEN L. ADLER,
Institute for Advanced Study
SYLVIA T. CEYER,
Massachusetts Institute of Technology
SUSAN L. GRAHAM,
University of California, Berkeley
ROBERT J. HERMANN,
United Technologies Corporation
RHONDA J. HUGHES,
Bryn Mawr College
SHIRLEY A. JACKSON,
Rutgers University
KENNETH I. KELLERMANN,
National Radio Astronomy Observatory
HANS MARK,
University of Texas at Austin
THOMAS A. PRINCE,
California Institute of Technology
JEROME SACKS,
National Institute of Statistical Sciences
L.E. SCRIVEN,
University of Minnesota
LEON T. SILVER,
California Institute of Technology
CHARLES P. SLICHTER,
University of Illinois at Urbana-Champaign
ALVIN W. TRIVELPIECE,
Oak Ridge National Laboratory
SHMUEL WINOGRAD,
IBM T.J. Watson Research Center
CHARLES A. ZRAKET, MITRE Corporation (retired)
NORMAN METZGER, Executive Director
OCR for page R6
Cosmology: A Research Briefing
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Cosmology: A Research Briefing
Preface
The Board on Physics and Astronomy (BPA) is reassessing the areasof physics that were examined by the Physics Survey Committee inits report, Physics Through the 1990s (National Academy Press, Washington, D.C., 1986). One of the eightvolumes of the report, Gravitation, Cosmology, and Cosmic-Ray Physics, was the subject of a National Research Council program initiationmeeting that I chaired in 1992. At that meeting, the need for reassessmentsin the areas of cosmology, neutrino astrophysics, and cosmic-rayphysics was identified.
The Panel on Cosmology, along with the Committee on Cosmic-Ray Physicsand the Panel on Neutrino Astrophysics, is part of this updatingeffort. Because of the connection to astrophysics and astronomy,the BPA has coordinated with the Committee on Astronomy and Astrophysics(CAA) in the conduct of this study. The panel is chaired by MarcDavis, who also chairs the CAA.
The research briefing format is intended to provide advice to programmanagers and policy makers on the opportunities for scientific advancesin a frontier field. The field of cosmology is an exciting frontierwhere astronomy, nuclear physics, and particle physics meet, andwhere we may be able to discover how the universe came to be as itis today.
David Schramm
Chair
Board on Physics and Astronomy
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Cosmology: A Research Briefing
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Cosmology: A Research Briefing
Contents
I.
OVERVIEW
1
What Is Cosmology?
1
What's All the Excitement About?
1
The Cosmic Questions
3
Why Do Research in Cosmology?
9
Why Now?
10
Summary
11
II.
THE COSMIC MICROWAVE BACKGROUND RADIATION
12
What Is the Cosmic Microwave Background Radiation?
12
What Do We Learn by Measuring the Properties of the CMBR?
12
The spectrum
12
Why are “bumps” in the CMBR so important?
13
Measurements of Anisotropy
14
Large-scale anisotropy
14
Medium-scale anisotropy
14
Small-scale anisotropy
15
III.
THE LARGE-SCALE STRUCTURE OF THE UNIVERSE
17
Galaxy Maps and Large-Scale Structure
17
What is large-scale structure, and why is it important?
17
Mapping the large-scale structure
17
The importance of uniform galaxy surveys
17
Theory of large-scale structure
18
Cosmic Velocity Flows
19
What are cosmic flows, and why are they important?
19
Measuring cosmic flows
20
Summary and Prospects for Large-Scale Structure
21
IV.
THE DISTANT UNIVERSE
22
Measuring the Cosmological Parameters
22
The Hubble constant, H0
22
The deceleration parameter, q0
23
The density parameter, Ω
24
Deep Imaging of Galaxies
24
Evolution of Large-Scale Structure Back in Time
25
Supernovae, Quasars, and Absorption Line Systems: Probes for Cosmology
25
Gravitational Lenses
27
What are gravitational lenses, and why are they important?
27
Measuring cosmological parameters with gravitational lenses
28
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Cosmology: A Research Briefing
V.
PHYSICS OF THE EARLY UNIVERSE
30
Primordial Nucleosynthesis and Dark Matter
31
Epoch of Inflation and Grand Unified Theories of Matter
32
Particle Theory and Dark Matter Candidates
33
WIMPs
34
Axions
35
Neutrinos
35
Summary of the Study of the Early Universe
36
VI.
CONCLUSION
37
GLOSSARY
38
REFERENCES AND FURTHER READING
41