Looking for Life Beyond Earth
Is There Anybody Out There?
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ON THIS PAGE
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After a
slump resulting from the "disappointing" Viking missions, the hunt
for ET is back.
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"If this discovery is confirmed,
it will surely be one of the most stunning insights into our universe that
science has ever uncovered."
-- Former President Clinton on possible Martian microbes
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Once it was asked in
whispers, or with winks. The timid among us, though undeniably curious, feared
raised eyebrows. Jokes about little green men.
Who could take such a
question seriously, yank it from the misty realms of science fiction and drop
it under the searchlight of science? Well, our national space agency, for one.
What's more, NASA seems pretty confident these days about the answer:
Astrobiology, as defined on an official agency web site, is "the study of
the living universe."
James Kasting is a bit more
guarded. Astrobiology is the search for life in the universe, the Penn State
professor of geosciences and meteorology says. Although the term itself may be
recent, "This is not a new field," Kasting said.
He got his first taste of
it as an undergraduate, reading Intelligent Life in the Universe, a 1966
book by Russian astronomer I.S. Shklovskii and a young American named Carl
Sagan, who later wrote, "We have every reason to believe that there are
many water-rich worlds something like our own." Kasting was hooked.
In recent decades, Kasting
acknowledged, the field has known a bit of a slump. It fell out of favor after
the 1976 Viking mission to Mars.
"Viking was very successful," he explained. "We learned a lot --
but we didn't find life. The perception was that all that money was
wasted."
Today, astrobiology is
back. The reports, over the last five years, of several planets
spotted outside our solar system -- the first of these by Penn State
astronomer Alexander Wolszczan -- have made all those potential watery Earths
that Sagan speculated about less hypothetical.
A great stir, too, has been
caused by the discovery, in a melon-sized meteorite plucked from the ice of
Antarctica, of a fossil-like remnant that, according to Kasting, looks a lot
like Earthly bacteria -- "except smaller by a factor of ten."
Martian microbes? Opinions
vary. The possibility was strong enough, however, to warrant a press conference
at which President Clinton said, "If this discovery is confirmed, it will
surely be one of the most stunning insights into our universe that science has
ever uncovered."
There have been other,
quieter, advances. We know now, for instance, that organic, i.e., carbon-based,
molecules -- crucial to any sort of life we can imagine -- are virtually
everywhere in the universe. And that, here on Earth, living organisms thrive in
what once seemed the unlikeliest of places, from hot springs to frozen lakes --
even far below the planet's crust.
ASTROBIOLOGY
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From a Warm Little Pond
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