Life on Mars?

Huge seas once existed on Mars, and it was warmer and wetter than first thought according to new evidence from NASA instruments orbiting and exploring the red planet.

A geological mapping project – using data from the Viking orbiter, Mars Global Surveyor and Mars Odyssey – found sedimentary deposits in a large region called Hellas Planitia, which suggests a large sea once stood there.

“This mapping makes geological interpretations consistent with previous studies, and constrains the timing of these putative lakes to the early-middle Noachian period on Mars,” said Dr Leslie Bleamaster, research scientist at the Planetary Science Institute.

Researchers believe fine-layered outcrops around the eastern rim of Hellas – a giant impact crater 2,000km-wide and 8km-deep – are likely to be sedimentary deposits formed through the erosion and transport of rock and soil from the Martian highlands into a standing body of water.

The data supports a lake in this area between 4.5 and 3.5 billion years ago, and that conditions on Mars may have been more favourable to support life at that time than they were on Earth.

NASA Mars Exploration Rover Spirit also suggests that Martian rocks found in the Columbia Hills of the Gusev Crater are rich in carbonate minerals. The carbonate shows the water was chemically neutral which also suggests more permissive conditions for life of the early planet.

Richard Morris, a NASA scientist from the Johnson Space centre said the rocks are 25% carbonate by weight – more than previously expected. “This is a significant jump,” he said. “And the amount is compelling evidence that there was some kind of water there.”

The mineral comes from carbonate-rich water interacting with rock which suggests to a warmer planet according to Dr Morris.

Further research in the region could provide clues about how the climate of Mars changed and where the water went.