The Evolutionary Biology Lecture of the Week for August 28, 2006 is now
available at:

http://aics-research.com/lotw/

The talks center primarily around evolutionary biology, in all of its aspects:
cosmology, astronomy, planetology, geology, astrobiology, ecology, ethology,
biogeography, phylogenetics and evolutionary biology itself, and are presented
at a professional level, that of one scientist talking to another. All of the
talks were recorded live at conferences.

This is the fifteenth lecture in a summer-long series on the new science of
astrobiology.

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August 28, 2006

Part XV: Astrobiology

Life and Death on Ice-Covered Worlds

Jere Lipps

University of California, Berkeley

24 min.

"Three feet of ice does not result from one day of cold weather."

— Chinese proverb

The notion that the sciences of paleontology and astrobiology would be somehow
linked seems quite jarring at first, but it only takes a moment's thought to
see the logic in the connection.

Water appears to be the sine qua non of life. Where liquid water disappears,
the life we know similarly disappears. Although water is now rare on the inner
planets of our solar system, it wasn't when the system was young. Mars and
Venus have since lost their oceans, and the Earth is destined to do so as well.
But there are places where water should persist for as long as the Sun exists.

In our search for life in the solar system, we're certainly going to look for
the signs of ancient life in the former ocean basins of the inner planets, and
thus paleontologists are likely to become a preeminent part of the
astrobiological community.

There are however other bodies in the solar system that appear to have large
extant oceans of water, such as the icy moons of Jupiter and Saturn, although
they are covered by kilometers of ice. While life could never exist on the
surface of these small worlds, here too — at least initially — we're going to
have to rely on standard paleontological processes while surveying the surfaces
to detect any life that may exist in the interior oceans.