- Ten million years ago it was awash with oceans of water.
Now it is desert dry. But research published today shows that organic life
could still be lurking on Mars.
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- Scientists will be poring over a slew of papers published
by the teams from the US space agency Nasa reporting the results garnered
from the two rovers, Spirit and Opportunity, that landed at the beginning
of this year and are still exploring opposite sides of the Red Planet.
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- Even before today's formal publication in the journal
Science, many scientists were abuzz over the earliest of the findings,
which suggested that water once flowed all over the surface, and is now
sequestered beneath it, probably still in liquid form. Furthermore the
gas methane, normally associated with biological activity, has been detected
in the atmosphere.
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- "Their findings such as sedimentary rocks [which
indicate oceanic activity] are very exciting," said Professor Colin
Pillinger, of the Open University, who led the team that developed the
European Space Agency's Beagle 2 lander.
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- "And they are also saying that there's methane in
the atmosphere there - which must mean a continuous supply, or it would
disappear. My preference is that [methane] is generated through a biological
supply - even the reprocessing of already-dead biological material by another
living source."
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- For Professor Pillinger the findings lend extra frustration
to the loss of the Beagle 2 lander, last heard of heading towards the Martian
atmosphere on Christmas Eve. But he declined to express regret: "We'll
get there one day," he said. "I wrote a letter to Nasa three
weeks ago suggesting a Beagle 3 lander as a stand-alone element to be included
with their 2009 Mars Science Laboratory mission. " He has yet to hear
back from the agency.
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- The work represents the most thorough geological examination
ever of a planet other than Earth, offering key insights into how its development
resembled and departed from that of our own.
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- The key surprise, said Dr Karl Miller, of the planetary
science group at Lancaster University, was the discovery of rock outcrops
- which in turn indicated how the planet's surface was eroded. He said:
"Most of Mars is covered with a thin veneer of dust, from millions
of years of wind erosion. That means you can't see much of what's been
going on, geologically speaking."
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- But seeing an outcrop told scientists what they needed
to know: that the rocks were formed by water action, and that huge volumes
of water must have flowed over the surface.
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- "Currently, the surface of Mars is incredibly dry,"
Dr Miller said. "But we think there's water in the poles, as ice,
and underground. It must have been driven to the surface by volcanic activity
until relatively recently - about 10 million years ago. That's only 1 per
cent of Mars's lifetime, because it is 4.5 billion years old. If it could
happen then, it could happen again."
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- The deep-lying water had to be liquid, because it would
be impossible for a volcano to melt enough ice quickly enough to flood
the areas shown to have been affected. "It would require about one
million cubic metres per second, which would be devastating on Earth,"
Dr Miller said.
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- The plethora of findings has deepened understanding of
Mars, and justified the $820m (£510m) cost of the landers - which
are still working, having long outlasted their planned mission of 90 Martian
days, 92 Earth days. Funding to run the landers runs out at the end of
September.
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- However, Dr Miller said it was still important eventually
to send humans to investigate the planet. "A geologist can notice
things and react in a way a machine can't," he said. "But right
now you can't get humans out there, and robots are becoming extremely impressive
- what these ones did wouldn't have been possible a few years ago."
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- Professor Pillinger cautioned: "I don't think it
would be responsible to send people until we're sure that there's life
there. And we should be very careful about bringing it back."
- © 2004 Independent Digital (UK) Ltd
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- http://news.independent.co.uk/world/
- science_technology/story.jsp?story=548380
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