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Copyright 2001 Agence France Presse   

                     Agence France Presse 

            June 8, 2001, Friday 6:08 AM, Eastern Time 

SECTION: Domestic, non-Washington, general news item 

LENGTH: 657 words 

HEADLINE: Eavesdropping on the universe 

BYLINE: Louise Daly 

DATELINE: CHICAGO, June 8 

BODY: When MIT oceanographer Nicholas Makris invited one of NASA's
chief scientists to speak to a group of students in August last year,
he never thought he would end up giving his guest a few pointers on
the subject of space exploration.

But from that random encounter evolved a collaboration which NASA and
Makris hope could help solve one of the remaining riddles of the
universe: "Is there life on Europa?"

The planet -- one of Jupiter's moons -- may not have the same name
recognition as Mars, but as one of just two planets in the solar
system that could potentially harbour "life as we know it," it's been
the subject of much scientific speculation.

At the root of debate is the question of whether the planet's ice
crust conceals a vast ocean capable of sustaining aquatic life, or
merely a slushy ice field that would support rudimentary bacterial
organisms at best.

"When Torrence Johnson addressed my group of freshmen, he said NASA
was considering landing a probe on the planet and using an implement
to burn its way through the ice cap to see what's underneath," said
Makris.

Staggered by the idea that NASA scientists might try to burn their way
through an ice cap that could extend as much as 100 kilometers down
into the planet's core, the professor of ocean engineering at the
Massachusetts Institute of Technology suggested a simpler alternative.

"I said why not use the sound-wave technology that we use to explore
oceans on earth?" recalled Makris, who was speaking here Tuesday at a
meeting of the Acoustical Society of America.

"They had talked to geologists, but it never occurred to them to talk
to oceanographers," explained Makris.

"The MIT group showed us the extraordinarily large amount of
information that you could get from a relatively simple and robust
device like a geophone (an acoustic sensor)," concurred Johnson, who
heads NASA's Galileo project.

"We're interested in doing the simplest type of experiment we can that
will tell us something about the planet."

The project to probe Europa's interior using ambient noise is based on
the assumption that the huge ridges seen criss-crossing the planet's
icy surface in pictures are in fact fractures in the ice cap.

These fractures would allow a series of surface microphones or sensors
to pick up acoustic energy from any naturally occurring sound to
determine whether the planet does in fact have a liquid interior.

Early indications are encouraging: magnetic data collected by NASA's
Galileo probe and published last year, suggest a layer of electrically
conducting liquid beneath the surface.

It could be decades, however, before the fruits of this collaboration
are seen: for now the only expedition the National Aeronautics and
Space Administration is contemplating to Europa is one that is still
some seven years off.

And the orbiter would not land on the planet, only circle it,
measuring movements in the moon's ice crust from space.

"We're maybe 20 years out," said Makris.

Such a long lead-in time for a space expedition is par for the course,
noted Aaron Thode, a researcher who has worked with Makris on the
project at the prestigious technical and engineering university in
Cambridge, Massachusetts.

"NASA started planning for the Galileo probe (which orbits Jupiter) in
the 1970s. It wasn't launched until 1989 and it took another six years
for it to reach Jupiter," he pointed out.

Meanwhile, the first step to any subsequent Europa expedition, would
be to test the technology on terra firma, possibly on the sub-glacial
Lake Vostock in Russian-controlled Antarctica.

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