From: LARRY KLAES (ljk4@msn.com)
Date: Sun Oct 27 2002 - 10:56:11 PST
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Fri, Oct 25, 2002, 10:13am To: rcleonw@webtv.net Subject: Fwd:
CU-Boulder Space Team Studying Water, Ice and Potential Life On Jupiter
Moon, Europa
Date: Fri, Oct 25, 2002, 10:06am From: baalke@jpl.nasa.gov
Subject: CU-Boulder Space Team Studying Water, Ice and Potential
Life On Jupiter Moon, Europa Reply to:
galileo-owner@www.jpl.nasa.gov To: undisclosed-recipients: ;
Office of News Services
University of Colorado-Boulder
3100 Marine Street, 5th Floor
584 UCB
Boulder, Colorado 80309-0584
(303) 492-6431
CONTACT:
Robert Pappalardo, (303) 492-6423, robert.pappalardo@colorado.edu Jim
Scott, (303) 492-3114
Oct. 24, 2002
CU-BOULDER SPACE TEAM STUDYING WATER, ICE AND POTENTIAL LIFE ON JUPITER
MOON, EUROPA
The oozing of glacial material in the floating ice shell on Jupiter's
moon Europa has important implications for future exploration of the
enigmatic moon and prospects of life in its ice-covered ocean, according
to a University of Colorado at Boulder professor.
Robert Pappalardo, an assistant professor in the astrophysical and
planetary sciences department and one of the world's foremost Europa
experts, said the icy moon is believed to contain an ocean some 13 miles
under its icy surface. Satellite images appear to indicate surface
warping -- including domes and reddish spots -- showing that "elevators"
of sorts transport material up and down from the ocean to the surface,
said the planetary scientist.
"Europa acts like a planetary lava lamp, carrying material from near the
surface down to the ocean, and, if they exist, potentially transporting
organisms from the ocean up toward the surface," he said. "Just a mile
or two beneath the surface, the conditions may be warm enough to allow
organisms to survive the journey."
The "thick shell" model of Europa has implications for the future
exploration of the moon and whether the existence of life is possible in
the lightless depths beneath the planet's surface, said Pappalardo. "It
would be very difficult for a future spacecraft to drill all the way
through a 13-mile-deep ice shell to search for life in the underlying
ocean. But the motions of glacial ice may transport ocean material, and
any life it might contain, to the surface."
Pappalardo and his research group at CU-Boulder's Laboratory for
Atmospheric and Space Physics are attempting to tie together pieces of
an elaborate puzzle to assemble a comprehensive model of how Europa
functions. The results are being reported at the Geological Society of
America meeting in Denver Oct. 27 to Nov. 1.
Under similar conditions in Arctic ice on Earth, organisms can remain in
a state of hibernation until exposed to warmer and wetter conditions, he
said. "If life exists in Europa's ocean, organisms might be carried on a
slow ride from the bottom to the top of Europa's icy crust. Sampling the
surface composition may provide direct insights into the nature of the
ocean deep below, and could plausibly reveal dormant organisms if they
exist within Europa."
CU-Boulder graduate student Amy Barr is developing a computer model to
illustrate the Europa ice motions, said Pappalardo. She is modifying a
computer model that has been used to understand Earth's plate tectonics
and to better understand Europa's geology, including how nutrients
created by ice irradiation at Europa's surface might be transported down
to the moon's oceans.
Barr's ice-convection model, the most sophisticated yet applied to
Europa, may show that organisms could thrive below the thick cap of ice,
Pappalardo said. It incorporates information on how the satellite's
thick ice shell is heated and how it flows as it is squeezed by the
gravity of Jupiter, which raises huge tides on Europa.
CU undergraduate Michelle Stempel is analyzing Europa's pattern of
cracks and ridges to understand how the Jupiter tides have fractured the
surface, and over what time scales the cracking has occurred. By
matching stress patterns to surface geological features, she is studying
where and how the surface cracks are created in response to short- and
long-term deformation of the thick icy shell overlying an ocean.
Pappalardo also has teamed with Francis Nimmo of University College,
London, to understand the similarities and differences between Europa
and its sibling Jovian moon, Ganymede. Ganymede may hide an ocean
beneath its icy crust much deeper than Europa's, although Ganymede's era
of geological activity has likely long ceased. By analyzing the
topography of fractures on Ganymede, the two scientists have determined
that Ganymede was once nearly as warm inside as Europa is today.
"This has important implications for the history of Ganymede, and also
for how Europa's surface is shaped today," Pappalardo said. "Ganymede
may be a fossil version of Europa." The two scientists found similar
internal and external forces that probably have influenced the two
moons, but with different geological expressions.
In addition, Pappalardo is working with Nick Makris of the Massachusetts
Institute of Technology to study how a future Europa lander could
precisely determine the depth and thickness of Europa's ocean, using the
same techniques routinely used by the Navy to measure the depth and
composition of Earth's oceans. The two are presenting back-to-back talks
at Denver's GSA meeting to illustrate how the proven terrestrial
technique can apply to the exotic environment of Europa.
Pappalardo recently served on a National Research Council panel that
reaffirmed a spacecraft should be launched in the coming decade with the
goal of orbiting Europa. The Europa Geophysical Explorer would have
scientific objectives that include confirming the presence of an ocean,
remotely measuring the composition of the surface and scouting out
potential landing sites for a follow-on lander mission.
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