Ocean Existed on Mars, Evidence Indicates

It wasn’t anywhere near as big as Noah’s worldwide flood – but evidence is pouring in from a Mars-orbiting satellite that a vast plain on the Red Planet must once have held a deep ocean bigger than all the Great Lakes put together.

And if indeed that ocean was so huge, scientists say, then its waters must have warmed the martian climate – enough, perhaps, for some forms of life to evolve.

The plain is where the rover Opportunity landed in January, and the new observations come from instruments aboard NASA’s Mars Odyssey satellite, which has been orbiting the planet for three years and already has detected signs of water or ice in many other areas near the surface.

“It’s the strongest evidence yet for a large body of water on Mars long ago, and obviously water is a key to the existence of life,” said planetary geologist Brian Hynek at the University of Colorado’s Laboratory for Atmospheric and Space Physics. “This isn’t evidence arguing for life itself, although it does argue for the possible habitability for life.

“It certainly argues that this martian area we’ve examined is a place where future missions should be looking for signs that life may once have existed there.”

In a report published yesterday in the journal Nature, Hynek estimates that Odyssey’s ocean must have covered at least 127,000 square miles. He predicts that continued findings by the spacecraft will show the body of water was considerably larger.

The ocean, he said, probably covered the martian plain some 3.7 billion years ago, and left layered stacks of sediments as the waters vanished over the millennia.

Hynek has analyzed images from the Odyssey spacecraft’s camera and readings from its thermal emission spectrometer, which measures the particle sizes of the material on the martian surface.

When Opportunity landed inside a small martian crater on the plain, its instruments detected abundant evidence of an iron oxide mineral called gray hematite – a chemical that is almost always formed from iron in standing water.

The Opportunity scientists, led by Steven Squyres of Cornell, also detected sulfates in the crater’s bedrock. Taken together, the hematite and the sulfates provided strong evidence that the water in the crater had been salty, Squyres said.