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Further evidence that Mars once had oceans emerges


February 8, 2012

Mars Express has used its MARSIS radar to give strong evidence for a former ocean of Mars (Image: ESA, C. Carreau)

Mars Express has used its MARSIS radar to give strong evidence for a former ocean of Mars (Image: ESA, C. Carreau)

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The European Space Agency (ESA) has provided more evidence that suggests the surface of Mars was once home to an ocean. Featuring ground-penetrating radar capabilities, the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) radar aboard the ESA's Mars Express spacecraft has detected sediments like that seen on an ocean floor.

In 1877, with the aid of a 22 cm (8.6 in) telescope, Italian astronomer Giovanni Sciaparelli produced the first detailed map of Mars, which featured what he called canali. Although canali actually means "channels" in English, it was popularly mistranslated as "canals," which, along with books by Percival Lowell, helped foster the popular notion of water and life - including Martians - on the Red Planet's surface. Although these "canals" were later proven to be an optical illusion, these myths weren't dispelled until NASA's Mariner missions in the 1960's.

Yet more recent mapping efforts still point to there being liquid water on the planet's surface at some point in its history. It is within the boundaries of features tentatively identified in images from various spacecraft as shorelines that MARSIS detected sedimentary deposits reminiscent of an ocean floor.

"MARSIS penetrates deep into the ground, revealing the first 60 - 80 meters (197 - 262 ft) of the planet's subsurface," says Wlodek Kofman, leader of the radar team at the Institut de Planétologie et d'Astrophysique de Grenoble (IPAG). "Throughout all of this depth, we see the evidence for sedimentary material and ice."

The sediments detected by MARSIS are areas of low radar reflectivity, which typically indicates low-density granular materials that have been eroded away by water and carried to their final resting place.

"We interpret these as sedimentary deposits, maybe ice-rich. It is a strong new indication that there was once an ocean here," says Jérémie Mouginot, from IPAG and the University of California, Irvine.

Two oceans at different times in Mars' history have been proposed - one 4 billion years ago when warmer conditions prevailed, and one 3 billion years ago when geothermal activity may have caused subsurface ice to melt and flow into areas of low elevation.

Dr Mouginot estimates that this latter ocean would have lasted only a million years or less, with the water either being frozen in place underground again, or turned into vapor and released into the atmosphere.

"I don't think it could have stayed as an ocean long enough for life to form," he says, suggesting astrobiologists would have to look further back into Mars' history when liquid water existed for much longer periods.

But the ESA says the MARSIS findings provide some of the best evidence yet that large bodies of water once existed on the surface of Mars and that liquid water played a role in martian geological history.

"Previous Mars Express results about water on Mars came from the study of images and mineralogical data, as well as atmospheric measurements. Now we have the view from the subsurface radar," says Olivier Witasse, ESA's Mars Express Project Scientist. "This adds new pieces of information to the puzzle but the question remains: where did all the water go?"

The ESA says the Mars Express spacecraft, which was launched in 2003 and has been granted five mission extensions - the latest until 2014 - will continue its investigations with the hope of providing an answer.

Source: ESA

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Now I\'m for sure not going there. No oceans mean no fishing!


waste of money, what they are going to start shipping water to mars now ? there is no life stop wasting money. we have life here on earth spend that money and built something that would stop it from becoming another mars.

Sukhpreet Singh Boparai

@ Sukhpreet Singh Boparai

You sound like one of those people that don't want any exploration at all. You'd still have us living in caves and hunting meat with spears. There are way to many nay-sayers in this world as it is. If you don't like it fine. Then ignore it. There are more than enough people with vision to see the benefits of going there. There probably were people saying what is the use of the new world in Columbus's time also. Stop being so pessimistic about all new ideas.


Some day earth will be uninhabitable. It has happened about four times. It could happen any time in less than a generation. We (our species) has had a great run. Time to leave. Just as we had to leave the womb to grow and survive, our place is in space. Our future is there. Those who stay will perish. Not maybe, but for sure, someday. I was born ready, psychologically. We just need to shake off our chains (government) and get going.


Is there any live in their? and what are they? may be\"

Okechukwu D Odinaka

Here is a thought. Mars looks like it may have suffered a direct hit by a planetoid. A direct hit on one side of the planet would send a shock wave thru the planet which would erupt on the opposite side, sending a large portion of the planet off into space. Maybe causing the creation of Deimos or Phobos and blasting away surface water.

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