Mars still has oceans of water buried below the surface, study finds

Billions of years ago, geological evidence suggests that the cold, dry red planet was much bluer. There was enough water collected from pools, lakes, and deep oceans to cover the entire planet in an ocean about 100 to 1,500 meters (330 to 4,920 feet) deep. This is roughly equivalent to half of the terrestrial Atlantic Ocean.

The question is: what exactly happened to all that water?

While water can be found frozen in the Martian polar caps, scientists had previously suggested that the water flowing on Mars had escaped into space due to the planet’s low gravity.. And while water did leave Mars that way, new study backed by NASA says a lot of its water is still on the planet, trapped in its crust.

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“Atmospheric escape does not fully explain the data we have on how much water once existed on Mars,” said Eva Scheller, lead author of the article published in the journal Science.

How the researchers estimated the water on March

Scheller and his colleagues used data from Mars rovers and orbiters as well as analyzed meteorites to study the amount of water on the Red Planet. at the start and how much he lost over time.

One way to do this is to analyze the hydrogen levels in the planet’s atmosphere and rocks. Water is made up of both hydrogen and oxygen, but not all hydrogen atoms are created equal. Most of them have only one proton in the nucleus of the atom, while the so-called “heavy” hydrogen has an extra neutron.

NASA / JPL

Ordinary hydrogen has little trouble escaping the gravity of a planet than heavier deuterium. The ratio of deuterium to hydrogen (D / H) in the planet’s atmosphere therefore reflects the loss of Martian water.

“Atmospheric escapes clearly played a role in the loss of water, but findings from the last decade of missions to Mars showed that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased availability. of water over time, “says Bethany Ehlmann, professor. of Planetary Science and Associate Director of the Keck Institute for Space Studies.

When water and rock meet, a process called chemical weathering can take place, forming clays and other hydrated minerals that contain water. as part of their mineral structure.

And while Mars still has between 30% and 99% of its water trapped in the crust, Scheller warns that it won’t be easy for future astronauts to easily extract water for their use.