for ; Mon, 23 Mar 1998 10:19:31 -0500 (EST)
From: Stig_Agermose@online.pol.dk (Stig Agermose)
To: updates@globalserve.net
Date: Mon, 23 Mar 1998 12:50:21 +0100
Subject: Carried By Comets? Life Forms In 100,000-Year-Old Antarctic Ice=20
>From the San Francisco Chronicle. URL:
Scientists Find Life Forms in 100,000-Year-Old Antarctic Ice
They may be clues to whether there's also life on Europa
=20
David Perlman, Chronicle Science Editor=BF
Tuesday,=BFMarch 17, 1998=20
                                                  =20
American and Russian scientists, seeking clues to possible life on one
of Jupiter's major moons, have found an astonishing array of living
organisms in layers of Antarctic ice hundreds of thousands of years
old.=20
The search for new evidence of how extremely hardy Earth life can be
has been spurred by recent dramatic images of the Jovian moon Europa.
Deep cracks, ridges and gaps in Europa's icy surface have revealed
slush and icebergs that apparently float on seas of water.=20
To assess whether the slush or water might hold life, researchers have
been exploring deep Antarctic ice cores more than 100,000 years old --
and have detected a variety of bacteria, algae, fungus spores and other
one-celled plants called diatoms.=20
This week, two of the scientists, astronomer Richard Hoover and his
research partner Sabit S. Abyzov of the Russian Institute of
Microbiology in Moscow, are working at NASA's Jet Propulsion Laboratory
in Pasadena to analyze samples from the ice cores, which were retrieved
by the Russians after drilling nearly a mile deep at their Vostok
research station in Antarctica.=20
ANCIENT COMETS=20
The frozen organisms may have been carried to Earth inside ancient
comets, the scientists believe.=20
Hoover, an expert on diatoms, is from NASA's Marshall Space Flight
Center in Huntsville, Ala., the place where Abyzov recently brought
samples of the deep Vostok ice cores. There, he and Hoover examined
them with the center's highly specialized Environmental Scanning
Electron Microscope.=20
This instrument uses X-rays to scan samples, but unlike more
conventional versions of such microscopes, the samples do not need to
be coated with gold to reflect the X-rays. Thus, signs of life in the
material are not hidden by the gold coating, Hoover said.=20
"We've seen some really bizarre things that we've never seen before,"
Hoover said.=20
At the Jet Propulsion Laboratory, meanwhile, Hoover and Abyzov are
enlisting the help of microbiologist Kenneth Nealson in an effort to
identify the species of the microscopic organisms they have seen.
Nealson is part of the laboratory's new astrobiology division, where
scientists are studying the evolution of planets and life both within
and beyond the solar system.=20
GALILEO SPACECRAFT=20
When the first images of Europa were transmitted to Earth last year
from the Galileo spacecraft that is now orbiting Jupiter and its major
moons, the pictures showed clear evidence that what was once thought to
be a solidly frozen ice crust covering the planet's entire surface is
actually warmed in part by some interior heat source.=20
That discovery, in turn, aroused fervent speculation about the
possibility of life.=20
"The combination of interior heat, liquid water and infall of organic
material from comets and meteorites means that Europa has the key
ingredients for life," declared Brown University geologist James Head,
a member of the Galileo team when the latest images from Europa were
released earlier this month.=20
Hoover goes even further, noting in an interview that some of the
clearest images of Europa's icy regions show colored material. Some
spots on the slush, he said, seem to be reddish, some bear a green tint
and some are golden brown.=20
"I get excited in Antarctica when I see golden brown ice," Hoover said,
"because to me golden brown means diatoms, and that's what shows up in
the ice cores from Vostok, too. It's a safe guess that colors like that
could come from biology anywhere."=20
Even deeper core samples from the Vostok station are still stored in a
laboratory freezer in St. Petersburg, and later this month Hoover and
Abyzov will bring them back to Hoover's laboratory for analysis.=20
The stored samples, the deepest of all the Antarctic cores, came from a
drilling venture that was deliberately stopped at 3,610 meters -- more
than two miles down, where the ice layer is 400,000 years old.=20
The reason for the halt was a dramatic one: The spot was almost exactly
100 meters above the surface of a 155-mile-long warm water lake that
Soviet radar showed to be directly beneath their research station.=20
UNCONTAMINATED LAKE=20
Russian and American scientists do not want to risk contaminating the
lake with coring equipment because they eventually hope to seek
evidence of life in the lake itself.=20
As a result, the National Aeronautics and Space Administration,
together with Russian researchers, is planning ways to design a
completely sterile robotic life-detecting instrument that can reach the
lake and emerge with uncontaminated water samples. The device has
already been named a "Cryobot," and teams from both nations will be
meeting in San Diego this summer to discuss strategies for building it.=20
"That lake is one of the most precious resources on Earth," Hoover
said. "It's the best analogue of Europa we have, and when we hunt for
life down there, we'll have to be as careful about contamination as we
would be when we bring back samples from the planets." Get a
printer-friendly version of this article=20
=A91998 San Francisco Chronicle=BF
=20
ON THE GATE
Wire up, plug in, and log on: *Technology on The Gate.=20
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