The oceans that Mars lost


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The lost oceans of Mars

New data from a six year study of the water in the modern Martian atmosphere have allowed scientists to estimate the amount of water Mars once had.

About four billion years ago, the young planet would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres. “Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, a scientist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA, and lead author of the new paper.

The image on the right is an artist’s conception of the oceans that would have existed on Mars, based on modern elevation data.

I must note that this conclusion, the size of the lost Martian ocean, is based on the assumption that the isotope ratios of Martian water started out the same as the Earth’s. While this is a reasonable assumption, it does not have to be true. Nonetheless, these conclusions, using ground-based telescopes, do match up with similar data obtained by Curiosity.

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4 comments

  • Ezzy G

    I have recently turned my attention to the study of Mars and the inner asteroid belt. One theory is that there was a collision of two bodies that stripped the now Red Planet of it’s atmosphere and left a heck of mess that we now call the asteroid belt… My question is: Why the 4 Billion year date on the Mars ocean account? How is that being calculated? I believe Mars may have had oceans at some point in the past but this is not compatable with the 4 Billion year timeframe… Could it have happened several thousand years ago? If not, why and how can we say with any authority?

  • PeterF

    One theory that would seem plausible is that Mars was hit by a large asteroid creating both the Hellas Basin and Tharsis Mons. In the trilogy; “Red Mars, Green Mars, Blue Mars” the central theme is the terraforming of the planet, exploring some of the foreseeable problems (not the least of which is the opposing political groups). An interesting point the books made was that even if the oceans were recreated, the highlands would still have an almost airless environment.

  • Max

    I also have a problem with the 4 billion year timescale. It seems to be a wild guess… unless it was formulated on the observation of the lack of large salt basins in the low spots (Hellas Basin) on the planet that would indicate leftover residue from a large ocean. In 4 billion years the salts can be broken down by sunlight or covered in Martian dust. (meteor impacts would uncover much that the Rovers could easily find)

    The timescale, for example, Pangaea. When all of our continents were hooked together in one mass, was a mere half a billion years ago.
    I believe this is when the moon collided with the earth and deposited 2 miles deep of the lunar crust exposing the moons mantle.
    This is what created our continents. (it also explains Continental drift, fossil fuels, heavy metals in the crust of the earth, the black scorch marks of obsidian seas on the moon, ect…)
    As for Mars having an ocean, I believe that would give mars enough mass to retain that ocean permanently as well as a thick atmosphere. But it doesn’t have either.
    It could have been a moon of the planet that created the astroid belt, and it may have been covered in ice of methane and ammonia like Jupiters Moons before it came to close to the sun and the lighter gases evaporated and melted away into space. The ice caps is all that is left.

    If I was to terraform a planet in our solar system, I would first do Venus, and then Saturn. Genetically modified resilient bacteria that will float in the upper atmosphere of both planets would eat the carbon dioxide and release oxygen, converting their atmospheres to water. With plenty of food, and self replicating bacteria. No natural enemies or control agents, the planets would soon be covered in the dead bodies of bacteria (carbon rich soil) that will grow plant life. Both planets may end up being Waterworlds, but humans could live there comfortably. (Saturn only has one 10th more gravity than the earth and both planets are much too hot in there present condition, but water will cool them off quickly as it does on our planet)(I know, it would take thousands of years but it would be worth it for the future)
    I think colonizing the airless low gravity of the moon or mercury makes much more sense than the nearly airless slightly higher gravity of Mars. Either way the colonist will need to live underground or in domed cities.

  • pzatchok

    Mars can not be terraformed because of its lack of magnetic field.

    Like Earth it needs that field to keep the solar winds from scavenging any atmosphere away and sending it off into space.

    http://www.planetary.org/blogs/emily-lakdawalla/2008/1710.html

    “Mars’ current magnetic field is very weak, with strengths of at most about 1.5 nanotesla. Earth’s, by comparison, is about 50 microtesla, which is 50,000 nanotesla, or more than 3,000 times stronger than Mars’. Earth’s magnetic field is supported by an internal dynamo; Mars must once have had a dynamo, which would have magnetized its rocks, but then the dynamo shut down. “

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