October 6, 2003
Geobiologist Kenneth Nealson to discuss the search
for life on other planets in public lecture
By Tim Stephens
If life exists on Mars, how would we know? Scientists have been grappling
with this deceptively simple question for years.
The basic proposition is this: If you have a rock from Mars,
or any other extraterrestrial site, what can you do to decide
if life is, or ever was, present?
Kenneth Nealson, the Wrigley Professor of Geobiology at the University
of Southern California, is a leading authority on this issue, which
he will address in a public lecture on Thursday, October 16.
Nealson's talk is the third Halliday Lecture, a public lecture series
sponsored by the UCSC Department of Astronomy and Astrophysics and the
UC Observatories/Lick Observatory. The lecture, "Recognizing Life
Under Strange and Distant Rocks," begins at 8 p.m. in the Music
Center Recital Hall. It is free and open to the public.
Nealson is a recognized pioneer of the young interdisciplinary field
of geobiology, which studies the interrelation between the chemistry
of life and the mineral and metal composition of the Earth. His recent
interests have been directed toward the microbiology of life in extreme
environments. He has chaired several NASA task groups charged with evaluating
techniques in the search for nonterrestrial life in the solar system,
particularly on Mars.
The basic proposition is this: If you have a rock from Mars, or any
other extraterrestrial site, what can you do to decide if life is, or
ever was, present? Life on other planets may take forms completely unlike
those on Earth. But scientists can use physical and chemical measurements
to search for things that "shouldn't be there," Nealson says.
This inferential method may be necessary for finding unknown extraterrestrial
life forms, and it involves a decidedly nonbiological approach, he says.
At USC, Nealson is affiliated with the Departments of Earth Sciences
and Biological Sciences. Before joining the USC faculty in 2001, he
was a senior scientist at the Jet Propulsion Laboratory in Pasadena.
The Halliday Lecture Series is made possible through the generous support
of John Halliday to promote public awareness and appreciation for astronomy
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