From studies of the martian surface we believe there is conclusive evidence that running water existed on Mars some time before 2 billion years ago. Because Mars has such a small mass, its gravitational field could not have held onto an atmosphere thick enough to allow liquid water to exist on its surface probably sometime after its first billion years of existence, so it would seem the most favorable, Earth-like conditions for life existed when Mars was about 1-2 billion years old. This also coincides with Earth fossil records which show bacterial life existing on Earth between 700 million and 1 billion years after Earth was formed. We think that life could have arisen simultaneously on Earth and Mars, but that soon after it established itself on Mars, the planet's surface water evaporated, or solidified as permafrost below the martian surface, and the planet's atmosphere finally evaporated. Hopefully, there is bacterial martian life existing today under the surface of Mars. bacteria are very hardy and adaptable, and do not need free gases to survive. They do need some form of water. We don't know if bacteria can live on ice!
The evidence for large bodies of liquid water is pretty convincing as this Brown University press release implies from recent NASA Mars Orbiter studies: .
In an article to be published in Science magazine Dec. 10, 1999, Brown University planetary geologist James Head and five colleagues present topographical measurements which they say are consistent with an ocean that dried up hundreds of millions of years ago. The measurements were taken by the Mars Orbiter Laser Altimeter, an instrument aboard the unmanned spacecraft Mars Global Surveyor which is circling the planet. Head's team set out to test the hypotheses of scientists who suggested the possibility of oceans on Mars in 1989 and 1991. The team used data from the Mars Orbiter Laser Altimeter, which beamed a pulsing laser to Mars' surface. Scientists measured the time it took for the laser to return to the satellite; the laser traveled a shorter length of time from mountain peaks and longer from craters. MOLA is the first instrument to provide scientists the information required to construct a topographic map of the entire surface of the planet. For years, scientists have known about channels in which water once flowed into the northern lowlands on the surface of Mars. "The question is whether it collected in large standing bodies," Head said. "This is the first time we could get instruments to comprehensively test these ideas."
The above picture represents what Mars would have looked like with its major ocean reinstated.
Copyright 1997 Dr. Sten Odenwald
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