New Map Suggests Huge Ocean Once Dominated Mars' Northern Hemisphere

By Andrew Moseman | November 27, 2009 8:05 am

marsocean425Scientists have long suspected that Mars was once a wet place, and that water helped to shape the geography we see there today. Now, thanks to a study published in the Journal of Geophysical Research, we don’t have to simply imagine what a watery Mars might have looked like long ago—geographers have created this new map of the Red Planet covered in blue water.

This new research addresses the longstanding question of whether surface water carved features, or whether other processes like groundwater sapping could’ve been involved. The new map, created by a computerised analysis of satellite data, shows that some regions of Mars had valley networks almost as dense as those on Earth. ”It is now difficult to argue against runoff erosion as the major mechanism of Martian valley networks,” said Professor Wei Luo, from Northern Illinois University in the US, who led the research [The Telegraph]. Instead, he argues, there must have been rivers on Mars long ago to create such dense networks.

The only previous map of martian valleys, created by hand and based on 1990s satellite images, showed a far less extensive river system. But Luo’s map was created “semi-automatically” by processing new satellite data, which extrapolated the existence of a huge ocean in the planet’s northern half. The Martian surface is characterized by lowlands located mostly in the northern hemisphere and highlands located mostly in the southern hemisphere. Given this topography, water would accumulate in the northern hemisphere, where surface elevations are lower than the rest of the planet, thus forming an ocean, the researchers said in a statement today [].

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Image: Wei Luo, Northern Illinois University

MORE ABOUT: geography, Mars, water
  • Brendy

    Would there have been a large ice cap in the Northern region leading to a lower sea level?

  • Jeff

    Where’s the water now?

  • Louis2

    I wonder what the size of Mars was then…and what its gravity was…if it still had its magnetic field

    then the other interesting question is…whether there is anything that could be done to terraform mars back into something similar and thus more liveable?

  • Nova Terata

    Jeff. The current pressure and temperature on Mars allows for Ice and vapor, but not liquid water, so the permafrost evaporates instead of liquifies. The lack of a strong magnetic field means there is little protection from solar winds. So the water evaporated into the atmosphere which was blown off into space by the solar winds.

  • Brian

    As Nova Terata says their is much less water now because of the magnetic field being so weak. Which in turn is due to the core not being like Earths or it being to small to sustain the planet. It is difficult to say but it could be due to the size of Mars that leads to the core being the way it is. I often wonder if Earth did not have the collision with planet Thea we would be in the same position today.

  • Beefarino

    Did Mars have a deflective magnetic field once?
    Can oceans of water form without protection from chaffing solar winds? I hope we can see a Martian fossil in our lifetime, much less a Martian shrimp living under ground now. I bet they are delicious.

  • terra incognita

    so who wants to earn extra credit points and overlay this map
    with the one in the article to see if cydonia could have had an ocean view – lateral, not vertical…?


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