Martian Ocean Held More Water than the Arctic
The National Aeronautics and Space Administration say there was once more water on the planet Mars than in the Arctic Ocean on Earth.
In a new study in the journal Science, space agency researchers say they compared the ratio of two different types of water found in the Martian atmosphere with the ratio of those waters trapped in a Martian meteorite dating back 4.5 billion years.
“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 at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper. “With this work, we can better understand the history of water on Mars.”
They say more than 4 billion years ago, Mars was covered with water 137 meters deep and that nearly all of it has since evaporated.
An ancient ocean containing the lost water would have covered 19% of the planet's surface. It would have had a greater volume than the Arctic Ocean, which contains 18,750,000 cubic kilometres (11.7 million cubic miles) of water.
By comparison, the Atlantic Ocean covers 17% of the surface of the Earth and contains more than 310 million cubic kilometres (192.6 million cubic miles).
By comparing the ratio of HDO to H2O in water on Mars today and comparing it with the ratio in water trapped in a Mars meteorite dating from about 4.5 billion years ago, scientists can measure the subsequent atmospheric changes and determine how much water has escaped into space.
The scientists say water may have covered Mars for a greater period than previously thought, meaning there may have been some form of life on Mars longer than what has been believed.
Michael Mumma, a senior scientist at Goddard who was also a lead author, added: “With Mars losing that much water, the planet was very likely wet for a longer period of time than was previously thought, suggesting the planet might have been habitable for longer.”
The planet is now largely a desert. NASA said its researchers were especially interested in regions near the north and south poles, because the polar ice caps are the planet`s largest known reservoir of water.
