February 6, 2012
New Research Shows Ocean Existed On Ancient Mars
The European Space Agency's Mars Express has revealed strong evidence that an ocean once covered part of Mars.
The spacecraft detected sediments reminiscent of an ocean floor within the boundaries of previously identified shorelines on Mars.
"We interpret these as sedimentary deposits, maybe ice-rich," researcher Dr Mouginot said in a statement. "It is a strong new indication that there was once an ocean here."
Other studies have concluded that Mars once had oceans, but the issue still remains controversial among scientists.
ESA said two oceans have been proposed, including one about 4 billion years ago, and another 3 billion years ago.
The ocean that occurred 4 billion years ago was during a time that the Red Planet had warmer conditions. The second ocean theorized was during a time when subsurface ice melted after a large impact, which created outflow channels that drained the water into areas of low elevation.
"MARSIS penetrates deep into the ground, revealing the first 60—80 meters of the planet's subsurface," Wlodek Kofman, leader of the radar team at IPAG, said in a press release. "Throughout all of this depth, we see the evidence for sedimentary material and ice."
The sediments revealed by the radar on MARSIS are low-density granular materials that have been eroded away by water and carried to their final destination.
Mouginot believes the water in the ocean would have either frozen back in place and been preserved underground, or turned into vapor within a million years or less.
"I don't think it could have stayed as an ocean long enough for life to form," Mouginot said in the press release.
ESA said this research helps provide some of the best evidence yet that there was an ocean on Mars.
The next step for astrobiologists is to look further back in Mars history when liquid water existed for longer periods.
Image Caption: New results from the MARSIS radar on Mars Express give strong evidence for a former ocean of Mars. The radar detected sediments reminiscent of an ocean floor inside previously identified, ancient shorelines on the red planet. The ocean would have covered the northern plains billions of years ago. Credits: ESA, C. Carreau
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