Bruce Jakosky, Ph.D., professor of geological sciences and director of the University of Colorado Center for Astrobiology, will speak at 7:30 p.m. April 19 in Brown Hall, Room 100. The lecture is free and open to the public.

Jakosky will explore the connections -- scientific and human -- between space exploration and our society.

"Twenty years ago, we thought that there was exactly one planet in our solar system on which life could exist: the Earth," Jakosky said. "Since then, revolutions in our understanding of life on Earth and of the nature of the planets and satellites in our solar system have changed this view. Today, we believe that life might have originated, or might exist, on up to a half-dozen planets or satellites in our solar system, and we are actively exploring Mars and Europa to look for life."

The recent discovery of planets orbiting other stars opens up the possibility that Earth-like planets and life could be widespread throughout our galaxy. As well as being of scientific interest, the issues of life elsewhere attract great public attention.

There are strong connections between science and society, especially between exploration and society, and, said Jakosky, these are all too often ignored by the science community.

"In particular, I will discuss the philosophical significance of our searching for extraterrestrial life, and what it would mean to find it -- or to search and not find it," he said.

The McDonnell Center for the Space Sciences is a consortium of Washington University faculty, research staff and students from the departments of Earth and Planetary Sciences, Physics and Chemistry, all in Arts & Sciences, and also the electrical engineering department. The center exists to encourage collaborative research efforts among scientists working on space science problems and projects that span traditional scientific disciplines through the sponsorship of cooperative research and formal activities such as the McDonnell Lectures.