The potential for life on other planets is one of the topics that NASA scientists will explore during the American Geophysical Union’s fall meeting in San Francisco.

A discussion about the search for extraterrestrial life will be held on Friday, Dec. 12, at 10:20 a.m. PST in room 2002-2004 of the Moscone Convention Center, San Francisco. During the session, “Astrobiology as a Unifying Theme for Solar System Exploration,” scientists also will discuss efforts to understand the origin and history of life on Earth. Astrobiology is an emerging interdisciplinary field that deals with life in the universe: its origin, evolution, distribution and future.

“The session is intended to examine the habitability of the planets in our solar system, to summarize our expectations about life (past or present) on other planets in this early stage of study and to develop strategies and instruments to be used in flight missions that will advance our understanding of life beyond Earth,” said David Morrison, senior scientist with the NASA Astrobiology Institute (NAI) at NASA Ames Research Center in California’s Silicon Valley, who will be one of the conveners of the session. Bruce Runnegar, director of the NAI, will be the other convener.

“This is an exciting time for astrobiology,” said Runnegar. “The flotilla of spacecraft that is heading toward Mars is expected to reveal features of the surface environment and geochemistry that will set the stage for future astrobiological missions,” Runnegar added.

“In proposing this session, we took advantage of several ‘focus groups’ formed under the auspices of the NASA Astrobiology Institute to bring together experts from many fields to address specific scientific problems or mission opportunities in astrobiology,” Runnegar said.

Speakers scheduled to participate in the session include: Bruce Jakosky, from the University of Colorado, Boulder; Jack Farmer and Ronald Greeley, both from Arizona State University, Tempe; Jonathan Lunine of the University of Arizona, Tucson; and David Des Marais from NASA Ames.

“Astrobiology compels us to understand the crucial details about how a host planet sustains its biosphere and influences its evolution,” Des Marais said. “Understanding how other planets might have sustained life, either today or in the distant past, requires a research program that fully integrates the fields of biology, planetary science and astronomy,” Des Marais added.

“This discussion comes at an appropriate time, as NASA is accelerating its exploration of the solar system by spacecraft,” Morrison said. Missions and plans to be discussed include: the Mars Exploration Rover (MER) mission (http://mars.jpl.nasa.gov/mer), the Mars Express missions (http://mars.jpl.nasa.gov/express/), the Huygens Titan Probe (http://saturn.jpl.nasa.gov/index.cfm) and the Jupiter Icy Moons Orbiter plans for future exploration of Europa, a Jupiter moon, (http://www.jpl.nasa.gov/jimo/).

So far, scientists have not discovered any direct evidence of life at any location beyond Earth, Morrison said. “Therefore, a great deal of the research now being carried out in astrobiology is directed at a better understanding of the origin and evolution of life on Earth,” Morrison explained.

During its first three billion years, only microbes populated Earth, according to Morrison. “This was not a stagnant time, however, as these microbes evolved sophisticated and varied capacities to live in a wide range of environments — environments that we call extreme — but that worked just fine for them,” he explained. “As we explore beyond Earth, we are looking primarily for microbial life. Thus, scientists use the microbes on Earth as a model or analog for what we may find beyond our own planet,” Morrison concluded.

More information about astrobiology is on the World Wide Web at:

http://nai.arc.nasa.gov and

http://astrobiology.arc.nasa.gov