STANFORD UNIVERSITY
EE 350 RADIOSCIENCE SEMINAR
Professor Len Tyler

Fall 2000-2001

Date: Wednesday, November 15, 2000
Time: 4:15-5:30 PM; Refreshments at 4:00 PM
Location: SEQ Teaching Center, Room #201


An Oasis in Space and Time

Prof. Donald Brownlee
Department of Atmospheric Sciences University of Washington

Abstract

Our planet is unique among known astronomical bodies for its ability to provide environments suitable for the long term survival of animals. Its "Garden of Eden" surface environment is the result of a remarkable sequence of astronomical, geophysical and biological events that cannot be expected to commonly occur elsewhere. In addition to its rarity in space, the Earth "as we know it" is also rare in time. For most of its 4.5 billion year lifetime, the Earth has been quite inhospitable to animal life. The window of habitability is small and the present age of animals will soon end as the Sun continues to brighten. In time our oceans will be lost to space, our moon will crash into us and Earth will again become just another lifeless planet in the Universe. The ultimate fate of Earth is uncertain. It might remain in solar orbit, it might escape solar system or it might fall into the swollen red giant sun.

About the speaker

Donald Brownlee is with the Department of Astronomy at the University of Washington (Seattle) where his primary research interest is the origin of the solar system as revealed through study of meteorites, comets and cosmic dust. As part of this work, he has devised methods for collection of dust using high-altitude aircraft. These materials, drifting downward through the atmosphere after being swept up by the Earth in its regular orbital motion, are now referred to as 'Brownlee Particles.' Professor Brownlee is Principal Investigator on NASA's Discovery Program sample return mission STARDUST, currently en route to a 2004 encounter with Comet Wild 2. He is also active in the field of astrobiology and is co-author of Rare Earth, a book dealing with the relationship of Earth's history, astrobiology, and the prevalence of intelligent life in the universe. Professor Brownlee is a member of the National Academy of Sciences and is a Fellow of the American Association for the Advancement of Science, the Meteoritical Society, and the American Geophysical Union.