Connecting Quarks with the Cosmos Eleven Science Questions for the New Century Committee on the Physics of the Universe Board on Physics and Astronomy Division on Engineering and Physical Sciences THE NATIONAL ACADEMIES PRESS Washington, D.C. www.nap.edu THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Govern- ing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineer- ing, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This project was supported by Grant No. DE-FG02-00ER41141 between the Na- tional Academy of Sciences and the Department of Energy, Grant No. NAG5-9268 between the National Academy of Sciences and the National Aeronautics and Space Administration, and Grant No. PHY-0079915 between the National Academy of Sciences and the National Science Foundation. Any opinions, findings, and conclu- sions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that pro- vided support for the project. International Standard Book Number 0-309-07406-1 Library of Congress Control Number 2003100888 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu and Board on Physics and Astronomy, National Research Council, NA 922, 500 Fifth Street, N.W., Washington, DC 20001; Internet, http://www.national-academies.org/bpa. Cover: Artwork 2002 by Don Dixon/cosmographica.com Copyright 2003 by the National Academy of Sciences. All rights reserved. Printed in the United States of America The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engi- neers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineer- ing programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Wm. A. Wulf is presi- dent of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sci- ences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Coun- cil is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Wm. A. Wulf are chair and vice chair, respectively, of the National Research Council. www.national-academies.org COMMITTEE ON THE PHYSICS OF THE UNIVERSE MICHAEL S. TURNER, University of Chicago, Chair ERIC G. ADELBERGER, University of Washington2 ARTHUR I. BIENENSTOCK, Stanford University2 ROGER D. BLANDFORD, California Institute of Technology SANDRA M. FABER, University of California at Santa Cruz1 THOMAS K. GAISSER, University of Delaware FIONA HARRISON, California Institute of Technology JOHN P. HUCHRA, Harvard-Smithsonian Center for Astrophysics JOHN C. MATHER, NASA Goddard Space Flight Center2 JOHN PEOPLES, JR., Fermi National Accelerator Laboratory2 HELEN R. QUINN, Stanford Linear Accelerator Center R.G. HAMISH ROBERTSON, University of Washington BERNARD SADOULET, University of California at Berkeley FRANK J. SCIULLI, Columbia University DAVID N. SPERGEL, Princeton University1 HARVEY TANANBAUM, Smithsonian Astrophysical Observatory2 J. ANTHONY TYSON, Lucent Technologies FRANK A. WILCZEK, Massachusetts Institute of Technology CLIFFORD WILL, Washington University, St. Louis BRUCE D. WINSTEIN, University of Chicago EDWARD L. (NED) WRIGHT, University of California at Los Angeles2 Staff DONALD C. SHAPERO, Director JOEL R. PARRIOTT, Senior Program Officer MICHAEL H. MOLONEY, Program Officer TIMOTHY I. MEYER, Program Associate CYRA A. CHOUDHURY, Project Associate NELSON QUIÑONES, Project Assistant VAN AN, Financial Associate 1,2Served for only phase 1 or 2 of the study (see Preface). v BOARD ON PHYSICS AND ASTRONOMY JOHN P. HUCHRA, Harvard-Smithsonian Center for Astrophysics, Chair ROBERT C. RICHARDSON, Cornell University, Vice Chair JONATHON A. BAGGER, Johns Hopkins University GORDON A. BAYM, University of Illinois at Urbana-Champaign CLAUDE R. CANIZARES, Massachusetts Institute of Technology WILLIAM EATON, National Institutes of Health WENDY L. FREEDMAN, Carnegie Observatories FRANCES HELLMAN, University of California at San Diego KATHY LEVIN, University of Chicago CHUAN SHENG LIU, University of Maryland LINDA J. (LEE) MAGID, University of Tennessee THOMAS M. O’NEIL, University of California at San Diego JULIA M. PHILLIPS, Sandia National Laboratories BURTON RICHTER, Stanford University ANNEILA I. SARGENT, California Institute of Technology JOSEPH H. TAYLOR, JR., Princeton University KATHLEEN C. TAYLOR, General Motors Corporation THOMAS N. THEIS, IBM T.J. Watson Research Center CARL E. WIEMAN, University of Colorado/JILA Staff DONALD C. SHAPERO, Director JOEL R. PARRIOTT, Senior Program Officer ROBERT L. RIEMER, Senior Program Officer MICHAEL H. MOLONEY, Program Officer TIMOTHY I. MEYER, Program Associate CYRA A. CHOUDHURY, Project Associate PAMELA A. LEWIS, Project Associate NELSON QUIÑONES, Project Assistant VAN AN, Financial Associate vi Preface The fall 1999 meeting of the National Research Council’s (NRC’s) Board on Physics and Astronomy (BPA) featured a stimulating science session on the frontiers of research at the intersection of physics and astronomy. Na- tional Aeronautics and Space Administration (NASA) administrator Daniel Goldin attended the session and at its conclusion asked the BPA to assess the science opportunities in this interdisciplinary area and devise a plan for realizing those opportunities. Robert Eisenstein, assistant director of the National Science Foundation’s (NSF’s) Mathematical and Physical Sciences Directorate, and S. Peter Rosen, associate director for high-energy and nu- clear physics at the Department of Energy (DOE), expressed their desire to work with NASA and supported the initiation of this study. The Committee on the Physics of the Universe was formed and held the first of its eight meetings in March 2000 (see Appendix A). Mr. Goldin strongly urged the BPA to finish the report in time for the recommendations to play a role in the science planning of the new admin- istration that would be taking office in 2001. To meet that ambitious goal, the BPA decided to divide the study into two phases: a first phase to assess the science opportunities and a second phase to address the implementa- tion of those opportunities. In carrying out the study, the BPA enlisted the help of the Space Studies Board (SSB). The charge to the committee was as follows: The committee will prepare a science assessment and strategy for this area of research at the intersection of astronomy and physics. The study will encompass astrophysical phenomena that give insight into funda- mental physics as well as fundamental physics that is relevant to under- standing astrophysical phenomena and the structure and evolution of the universe. The science assessment will be carried out as the first phase of the study over a period of 1 year. The assessment will summarize progress in ad- vii viii PREFACE dressing the key research issues facing the research community and evalu- ate opportunities for further progress. Among the science topics to be included in the science assessment are cosmology, the creation of matter and energy at the initiation of the universe, the dark matter known to pervade the cosmos, the dark energy that appears to be causing the expan- sion of the universe to accelerate, additional dimensions beyond the usual three of space and one of time, strong-field