April 13-15, 2000

Though speculations about our place in the cosmos are as old as thought itself, such speculations have remained largely theoretical in the past. But technical advances over the course of the last century have transformed cosmology from speculation to serious science, vastly expanding our horizons in space and time. A number of recent developments in our understanding of the universe have accounted for what some are calling a “golden age” in cosmology. It is clear that the time is right to explore the innovations that promise new cosmologies in the 21st century.

The confluence of powerful ideas and a flood of data made possible by new instruments and observatories (such as the Hubble Space Telescope and Keck telescopes, the Sloan Digital Sky Survey, and Tevatron at Chicago’s own Fermilab) are leading to great advances in our understanding of the origin and evolution of the universe. Scientists are now able to calculate with increasing accuracy the history of the Universe from the “quark soup” that existed a fraction of a second after the beginning to the highly stuctured universe we see 14 billion years later—with galaxies, clusters of galaxies, and even great walls of galaxies.

Several developments in particular are promising to revolutionize cosmological research in the coming decades. Theoretical work on the phenomenon of inflation is dramatically reshaping our conception of how the big bang and ultimately all matter and energy originated. New measurements have begun to support predictions from the theory of inflation, including the indication that the universe is flat. Thanks to satellite, balloon-borne, and South Pole based instruments, we are able to produce more detailed maps of the cosmic microwave background, the observable radiation left over from the big bang, and we are beginning to understand the nature of the elementary particles (called Cold Dark Matter) that hold the universe together.

There are some puzzles that remain to be worked out. Foremost among them is why the universe is speeding up and not slowing down! This discovery made two years ago was greeted with much excitement—the mysterious dark energy which is causing the Universe to speed up both the total amount of matter and energy known in the universe to that required to make it flat, as indicated by measurements of the microwave background. However, at the moment, we don’t have a clue as to what this dark energy is. There is also the mystery of the highest energy cosmic ray particles—where did they come from and how did they achieve such high energies?

Calling on expert voices in physics and astronomy, our seminar will explore in detail the hot big-bang model and its implications. In addition to offering an overview of recent changes in the cosmological picture, we will discuss the state of contemporary research on such topics as the cosmic microwave background, the intergalactic medium, the dark side of the universe, the large-scale structure of the universe, and other exciting developments in cosmology.

Speakers will include John Carlstrom (Astronomy and Astrophysics & Director, Center for Astrophysical Research in Antartica), Sean Carroll (Physics), Joshua Frieman (Astronomy and Astrophysics), René Ong (Physics), Michael Turner (Astronomy and Astrophysics & Physics), and Don York (Astronomy and Astrophysics).