NEW YORK: Mars once had a large ocean of water, some parts of it more than a kilometre and a half deep. But most of this was lost into space leaving Mars the desert we see today, according to research from the US National Aeronautics and Space Administration.
The scientists believe it could have contained 20 million cubic kilometres of water, about the volume of the Arctic Ocean. But 87 per cent of this evaporated and drifted off the planet over the past billion years or so.
What remains is held as ice mainly at the planet’s poles and probably under parts of the arid Martian surface.
“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, first author of a paper published in the journal Science.
If Mars were a perfectly smooth ball this much water would have covered the whole planet to a depth of 137 metres. But it is not smooth and the water would have accumulated in a large low spot, which on Mars means the great northern plains, the scientists say.
The resulting ocean would have covered half of the planet’s northern hemisphere, in some places to a considerable depth.
Obviously the scientists based at the Goddard Space Flight Centre in Maryland had no visual record to make their prediction, they had to calculate it in a round-about way by looking at the ratio of two kinds of water molecule.
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