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Cosmologists, physicists to ponder earliest moments of the universe at Cosmo-02 workshop Sept. 18 to 21 in Chicago

Journalists are invited to attend the workshop at no charge. To register, send an e-mail to

An international group of more than 200 scientists will attempt to shed light on the dark side of the universe and what happened in the first few fractions of a second of its existence at the Cosmo-02 workshop Sept. 18 to 21 at the Adler Planetarium and Astronomy Museum in Chicago.

The workshop is co-organized by the Center for Cosmological Physics at the University of Chicago, by the Adler Planetarium and by the Fermi National Accelerator Laboratory. The Center for Cosmological Physics is a Physics Frontier Center of the National Science Foundation.

Most of the presentations will focus on theoretical science, said workshop co-chair Sean Carroll, Assistant Professor in Physics at the University of Chicago. Over the last five years, observational astronomers working at their telescopes have answered one set of questions while opening up a whole new set, Carroll said. "Now it’s really turned over to the theorists to figure out how to make sense of this. We know much and we understand nothing."

They know, for example, that the observable stars and galaxies account for only 5 percent of the mass and energy in the universe. They call the mysterious 95 percent of the remaining universe "dark matter and dark energy." Dark matter is thought to consist of hypothetical particles that have not yet been observed in particle accelerators, but whose existence is inferred by measuring their gravitational pull. Dark energy is an exotic form of energy that causes distant galaxies to accelerate away from Earth.

"We’ve learned to describe these things about the universe, the dark matter and the dark energy, but we still don’t know what they are," Carroll said. "So I think that getting theorists together to talk about some of the crazier ideas is something for which the timing is right."

One important development that bolsters the workshop’s importance is the recent set of discoveries about subatomic particles called neutrinos and their interactions, said workshop co-chair John Beacom, the David N. Schramm Research Fellow at Fermilab. Neutrinos once were touted as a candidate for the dark matter.

"We’ve recently learned that neutrinos really can’t be a substantial component of the dark matter," Beacom said. "That puts us in an interesting position. No particle that we’ve ever seen in an accelerator or other laboratory could be the dark matter. That’s exciting."

The annual Cosmo workshop, which first met in 1997, brings together physicists and cosmologists who are attempting to merge two fields of study: particle physics and cosmology.

"It’s bringing together a unique group of people," said conference co-chair Evalyn Gates, vice president for research and education at Adler Planetarium. "It’s very international. It’s definitely going to be a series of talks about what’s going on at the very edge of this vibrant, active field."

The workshop participants this year will place a special emphasis on the extremely early universe, string theory and extra dimensions.

In this case, the extremely early universe means "the first zero seconds," Carroll said. Much research in recent years has focused on cosmic inflation, when the universe underwent a gigantic growth spurt in a fraction of a second just moments after the big bang.

"We’re at a state right now where people are beginning to think seriously about what happened before inflation," Carroll said.

String theory attempts to unite the four fundamental forces of nature that govern the motion of everything from the smallest subatomic particles to the largest galaxy clusters. In theory, a string is the fundamental building block of the universe that gives rise to all particles and exists in 10 dimensions rather than the three spatial dimensions of the known universe. Scientists are interested in string theory because it may help explain the conditions that appear to have prevailed in the earliest moments of the big bang.

"People believe that general relativity just breaks down at that point," Carroll said. "On the other hand, they don’t know how it breaks down or what replaces it. String theory is supposed to replace it and people are trying to think very hard right now about how that could actually work."

The conference will feature 27 plenary talks, as well as 72 talks in parallel sessions. Among the workshop speakers will be Wendy Freedman of the Carnegie Observatories and a leader in the effort to use the Hubble Space Telescope to measure the expansion rate of the universe. Freedman will present the opening remarks.

Other plenary speakers will be Alan Guth of the Massachusetts Institute of Technology and Lisa Randall of Harvard. Guth, who originated the widely accepted cosmological theory of inflation, will discuss "eternal inflation," the idea that inflation could still be occurring in certain regions of the universe. He also will give a public lecture at 7 p.m. on Thursday, Sept. 19, at the Adler Planetarium titled "Inflationary Cosmology and the Accelerating Universe."

Randall, a particle theorist, has proposed an influential scenario in which the known universe is embedded in an invisible extra dimension of spacetime.

The public is invited to view an electronic poster session put together by the scientists that may contain video clips, plots, and a variety of other images and graphics. As many as 12 different posters will be on view each day throughout the conference on 37-inch computer screens.

Poster sessions have long been a mainstay of academic conferences, but an electronic poster session is a new concept, Gates said. "This is an experiment. It’s never been done anywhere."

Although the posters will contain highly technical material, "the public can see science as it’s being done at the very edge," Gates said.

For more information, see the workshop Web site at

High-quality photos are available here.
Last modified at 01:55 PM CST on Friday, September 12, 2003.

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