From Smithsonian Magazine:
The Martian landscape is an arid expanse of craters and sandstorms, but scientists have spotted several signs that at one point in its life, the Red Planet was awash with blue waters. Scientists have theorized that much of the planet’s water was lost to outer space as the atmosphere dissipated.
But the planet’s vast oceans couldn’t have been lost to space fast enough to account for other milestones in Mars’ existence. The water must have gone somewhere else. A new study presents a solution: the water became incorporated into the chemical makeup of the ground itself. The research uses new computer models and found that if Mars once had a global ocean between 328 and 4,900 feet deep, then a significant amount of that water might now be stored in the planet’s crust.
“The fact that we can tell that there used to be a lot of water on Mars has really big implications for the potential for Mars to have had life in the past,” says planetary scientist Tanya Harrison, director of science strategy of Planet Labs, to Inverse’s Passant Rabie.
Read more: Mars’ Missing Water Might Be Hiding in Its Minerals by Theresa Machemer