23rd Annual Great Lecture in Astronomy

"Alien Worlds"

Dr. William Cochran
Research Professor
Department of Astronomy
McDonald Observatory
The Univesity of Texas at Austin

1:00 p.m. in POB 2.302 (Avaya Auditorium)

The public is invited to attend this lecture, which is sponsored by The University of Texas at Austin McDonald Observatory and Department of Astronomy Board of Visitors.

Abstract:
The last 20 years has seen a huge revolution in our understanding of planetary systems around other stars. Up until 1995, our solar system was the only one we knew about; now there are nearly 2000 known extra-solar planets. The Kepler spacecraft has revolutionized our knowledge of these systems, introducing us to types of planets we had never imagined could exist. If we make simple and logical extrapolations from the Kepler results, we come to the astonishing conclusion that nearly every star in the sky is accompanied by a planetary system! Planets probably started forming early in the history of our galaxy. There are nearby planetary systems that are more than twice the age of our solar system. The next logical question is: Do these other planetary systems also harbor life? Right now, we can only speculate on this. But the new generation of large telescopes, such as the GMT, will begin to provide some answers to these questions. The large aperture of GMT, along with its advanced technology instruments and detectors, will enable us to probe the atmospheres of nearby Earth-like planets. We will look carefully for evidence that life on these planets may have left detectable chemical signatures in their atmospheres. Perhaps we can finally begin to discover our neighbors. 

The Speaker:
When Bill Cochran first arrived at The University of Texas at Austin, he conducted observations and modeling of the atmospheres of the outer planets of our Solar System. He then became interested in planets around other stars, and in the late 1980s he started one of the early radial-velocity planetsearch programs. The search now uses the McDonald Observatory’s Harlan J. Smith (107-inch) Telescope and Hobby-Eberly Telescope. This research program has grown tremendously to include characterization of the planets, their atmospheres and the systems in which they live. He is a co-Investigator on the NASA Kepler spacecraft mission, which is now in its “K2” extended mission.