PARIS --Three-quarters of the 250 Mars science experts meeting to analyze the resultsfrom U.S. and European Mars probes believe life could have existed on Mars inthe past, and 25 percent think life could be there even now, according to apoll released Feb. 25.
The pollwas announced during a press briefing following the First Mars ExpressConference, held Feb. 21-25 at the European Space Agency's Estectechnology center in Noordwijk, Netherlands.
The resultsperhaps reflect the sober caution of scientists who refuse to jump toconclusions before conclusive evidence is in about the No. 1 issue on the mindsof everyone attending the conference, held to review a year's operations of Europe's Mars Express orbiter.
Everett K.Gibson of NASA's Johnson Space Center in Houston, who attended the meeting as aMars interdisciplinary scientist reviewing the results of all the Mars experiments,said the available data lends credence -- but as yet offers no proof -- to theidea that the methane and formaldehyde present in Mars' atmosphere is evidenceof underground life.
Gibson saiddefinitive proof likely will require a future Mars mission carryingsophisticated drills to penetrate beneath the Mars surface to take samplesdirectly or -- a preferred option -- to return them to Earth for laboratoryevaluation. "Mars is revealing her secrets, but slowly," Gibson said. "We needthose samples or in-situ measurements."
In a seriesof presentations on each of Mars Express' seven experiments, several scientistsstopped just short of saying that the evidence so far points to life buriedunder the surface of Mars away from the ravages of the solar wind.
Onepossible explanation for the absence of liquid water on the surface of theplanet is that Mars, which unlike Earth does not havea protective magnetic field, is being shorn of its surface by the solar wind.An estimated 100,000 kilograms per day of Mars surface material is blown offthe planet, according to Stas Barabash,lead scientists for the Mars Express ASPERA-3 experiment, which measures thephenomenon.
Vittorio Formisano, lead scientist for the Mars Express PlanetaryFourier Spectrometer, which is investigating Mars' atmosphere, said thediffering levels of concentration of methane and formaldehyde are cause foroptimism that life exists under the surface.
"We needmore work for a final conclusion," Formisano said,adding: "Life is probably the only source that could produce so much methane.The question is not any more, Was there life on Mars?The question is: Is there life on Mars today?"