spacetoday.net: Study finds Mars has been cold for 4 billion years

Posted: Sat, Jul 23, 2005, 11:01 AM ET (1501 GMT)
Hubble image of Mars

An analysis of meteorites of Mars has led scientists to conclude that the planet was too cold to support liquid water for the last four billion years, a finding that may diminish hopes of finding evidence of past or present life there. In a paper published in the July 22 issue of the journal Science, researchers at MIT and Caltech studied two nakhlite meteorites that came to the Earth from Mars. By measuring the amount of argon trapped in the rocks, they concluded that they had never been above the freezing point for more than brief periods of time over the last four billion years. The scientists note that this does not mean isolated oases of liquid water might have existed on the planet, but it does rule out wider expanses of liquid water on the planet in the last four billion years. That would mean that any microbial life that formed on the planet either died out billions of years ago or were restricted to any isolated warm spots.