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Recent information from Mars provides support for the controversial idea that large portions of Mars was covered by an ocean. Aside from moving science fiction closer to reality, if such a discovery is confirmed, it increases the chance of finding traces of life on the red planet.

An Ocean on Mars?

By: Jeffrey Caminsky

Mars--closest approach, 2007

Did Mars once have an ocean? Recent information from Mars provides support for this controversial idea, one that would move science fiction from bookshelves one step closer to reality.

Analyzing data from the Gamma Ray Spectrometer of NASA’s Mars Odyssey orbiter, an international team of scientists detected signs that suggest the presence of liquid oceans over much of the surface of our planetary neighbor. The spectrometer, which is capable of detecting elements buried more than a foot underground by tracing their gamma-ray emissions, picked up concentrations that have left intrigued scientists wondering whether they have finally found solid evidence of a liquid past on the now-dry planet.

In an article published in an special edition of Planetary and Space Science, the authors theorized that large bodies of water on Mars would leach out and concentrate elements like potassium, thorium, and iron along the ancient shorelines, as they often do here on Earth. So, taking data from the spectrometer, the scientists were able to compare the concentrations of these tell-tale elements with the topographical maps of the red planet, to see whether the patterns matched those we might find along a seashore. Their findings suggest the presence of two different oceans, perhaps covering a third of the planet and probably occurring at different times in Martian history. And their conclusions have spurred debate about the likelihood of finding traces of life on the cold and dusty planet.

Still, there is much work to be done, and not everyone is convinced. Due to the absence of tidal forces from a large moon, the shorelines on Mars look quite different than those on the Earth. And the source and fate of the water remains a mystery. Some speculate that volcanic eruptions heated the cold Martian air enough to usher in a warmer, wetter epoch for the planet; others remain as skeptical as ever.

The data adds information to fuel the debate, noted James M. Dohm, a planetary geologist from the University of Arizona who led the international team of scientists. But the debate would likely continue, he reflected—perhaps even after scientists are able walk the surface of the planet with instruments in hand.

Photo Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURAP, J. Bell (Cornell University), and M. Wolff (Space Science Institute, Boulder).