[Rockhounds] "Mars' missing atmosphere could be hiding in plain sight."

[Kreigh Tomaszewski]

New research suggests the atmosphere of Mars may be hiding in plain sight,
having been absorbed by minerals in the Red Planet's clays. If Mars'
envelope of gas did "go to ground" over 3 billion years ago, this could
explain how Earth's neighboring planet became so different from our world,
potentially losing its capability to host life.

Scientists know that the Red Planet
<https://www.space.com/47-mars-the-red-planet-fourth-planet-from-the-sun.html>
wasn't
always the arid and barren landscape that the Mars rovers Perseverance
<https://www.space.com/perseverance-rover-mars-2020-mission> and Curiosity
<https://www.space.com/17963-mars-curiosity.html> trundle across today.
Both of NASA's rolling robots have uncovered evidence that abundant water
flowed over Mars <https://www.space.com/17048-water-on-mars.html> early in
its 4.6 billion-year history. But for Mars to have had liquid water, it
must also have possessed an atmosphere to stop this water from freezing.
The big question for decades has been: where did this atmosphere go when
disappeared?

A team of researchers think that the answer has been under the noses (or
the tracks) of Curiosity and Perseverance all this time. In a paper
published in Science Advances, they argue that while water was present on
the Red Planet, it may have trickled through certain rock types and set off
a slow series of reactions that slurped carbon dioxide out of the
atmosphere. This would have then been converted into methane
<https://www.space.com/18339-mars-methane-alien-life.html>, a form of
carbon, and locked up in the clay surface of Mars
<https://www.space.com/13475-ancient-mars-water-underground-evidence.html>.
https://www.space.com/mars-missing-atmosphere-hiding-plain-sight-clay-methane