By Xinhua
Beijing : Scientists believe that early life forms on Mars were most likely snuffed out by the extremely salty water on the Red Planet, media reported Monday.
“In fact, it was salty enough that only a handful of known terrestrial organisms would have a ghost of a chance of surviving there when conditions were at their best,” said Harvard biologist Andrew Knoll, a member of the Mars rover science team.
When people add in the earlier findings about how acidic Martian water was, back in the era when the rocks now being studied were formed, the picture of the Martian environment becomes so forbidding that Knoll couldn’t think of any organism on earth that could survive.
“There aren’t that many of those environments around,” he observed. The organisms would have had to withstand the corrosiveness of water draining out from an acid mine as well as the salinity of water pooled on a salt flat.
Knoll’s findings are based on an analysis of the minerals sampled by Opportunity as it explored the Martian plain known as Meridiani Planum, where it landed just over four years ago.
The analysis looked at the present-day chemical content and worked backward in time, using a computer model as a “gauge of paleosalinity,” Knoll said.
Other evidence comes from an analysis of one of the more recent pictures to come from Opportunity, a close-up of a rock known as Gilbert. The slab is covered with the blueberry-like stones that have often been seen in Meridiani Planum. But it also sports what Knoll called “Cadillac-like fins” along an edge. He said those fins tell geologists that the rocks were formed by fluid flow but have been exposed to the elements for a long time.
“If there is a habitable niche, it’s underground” on the planet, said the head scientist for the mission, astronomist Steven Squyres of Cornell University in New York state.