They were wrong: Mars has much more water than formerly known


  • Mars is long known to be a dry planet.
  • Recently, researchers claimed that it has much more water than previously declared.
  • Its water never escaped into space, but has gone into its soil, rocks and clay.

Mars has long been known as a dry planet after it lost its magnetic field more than four billion years ago, exhausting its warmth and moisture. But researchers at the California Institute of Technology published a study on March 16, saying that this pre-conception is all wrong.

Mars is relatively dry, but the scholars posited that it still has much water, from 30 percent to a staggering 99 percent. Originally, Mars’ global equivalent layer (GEL), a unit of measure on the depth of water that spread evenly across the entire planet, was roughly ranging wide from 100 to 1,500 meters. Today, its water on the surface, almost trapped in its polar ice caps, has a GEL of only 20 to 40 meters.

The water only retreated into the Martian rocks and clay, instead of sputtering off into space.

In the process, water molecules rose into and escaped from the atmosphere, they split into free hydrogen and oxygen atoms — with hydrogen coming in two forms: ordinary hydrogen (with a single proton in its nucleus) and deuterium (with a proton and a neutron).

“The vast majority of hydrogen in the universe is just hydrogen,” said Bethany Ehlmann, professor of planetary science at Caltech and a co-author of the paper. “But there’s that tiny fraction that is deuterium. In the Earth’s ocean it’s almost one [heavy water molecule] in a million.”

Hydrogen behaves differently in the Martian atmosphere with the greater weight of deuterium. Free deuterium weighs amply to hang around in the air, as free hydrogen atoms that were once part of a water molecule escape into space.

Eventually, more hydrogen floats off the planet as more deuterium stays behind. This causes the ratio of deuterium to hydrogen to slow down.

“The loss of hydrogen is a sort of constant removal,” Eva Lingh Scheller, Caltech PhD candidate and the lead author of the paper, said. “Removing it from the total volume is going to give you a larger D/H ratio.”

The planet’s current D/H ratio is too low as discovered by the scientists. A great amount of Mars’ water never escaped, but has gone into the soil, rocks and clay, which is the most lavish mineral on Mars.

“If you suck the water out a different way and let the remainder escape to space, that solves the [D/H] conundrum,” said Ehlmann.

The fact that Mars could be greatly hydrated does not necessarily equate to the possibility of Martian life, as water molecules are dragged into the rocks and clay.

“You heat your rock to 300º or 400º C and then it would release its water,” Scheller said. “But there’s only a little there so you’d have to cook up a lot of rocks to get any appreciable water.”

Source: TIME

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