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European Space Agency scientists think that there was and could even still be life on Mars and want another European mission to the red planet to take new samples, a conference heard over the weekend.
"Mars is the most Earth-like planet in our solar system," said Agustin Chicarro, an ESA Mars Express project scientist said at the end of a week-long conference during which scientists from around the world discussed ESA's Mars mission findings so far.
They found a large ice sea near Mars' equator that was formed less than 5 million years ago and believe volcanic activity is still continuing on the planet's northern pole.
The findings, a year after a European launch started orbiting the planet, also serve as a stark warning to earthlings - Mars has no protective ozone layer and the surface is blasted by solar storms and deadly ultraviolet light.
Water vapour destroyed ozone on Mars and a recent increase of water vapour in Earth's stratosphere could be a potential threat to this planet's protective ozone layer that is probably linked to global warming, said scientist Jean-Loup Bertaux.
"Hints of life on Mars are getting stronger," said Vittorio Formisano, whose team found methane and formaldehyde on Mars.
He said there was so much methane produced on Mars that there was reason to believe the gas had organic origins. "Life is probably the only source that can produce so much methane," Formisano said.
Everett Gibson, of NASA's Johnson Space Center, said he held a poll among the 250 scientists at the conference on the question of whether they thought there had been life on Mars.
Some, 75 percent said yes. Asked whether they believed there to be life there now, 25 percent said they believed there is, and it is most likely in the form of bacteria, Gibson said.
Ice water
Jean-Pierre Bibring led a team looking for traces of water. "We found water, but not in the form we envisioned. "
There was no evidence of permanent oceans or lakes during the past three billion years and no extended areas with carbonates, and water on Mars today is only present as ice.
Gerhard Neukum, of the High Resolution Stereo Camera team, showed several pictures of a "frozen sea" near the equator. The area is some 800 by 900 kilometers and the original depth was some 50 meters with ice rafts of up to 30 kilometers in size.
Mars remains a very hostile environment - a fierce solar wind is blowing away planetary materials and penetrates deep down the dayside atmosphere while during polar nights, the atmosphere is minus 130 C to minus 143 C.
But David Southwood, ESA director of science, said Europe should return to Mars and needs to find money for a second mission to probe deeper into its mysteries.
(China Daily February 28, 2005)
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