Mars' Long-Lost Atmosphere Might Be Hiding in Plain Sight

Newsweek writes that the missing atmosphere of Mars 'may be locked up in the planet's clay-rich surface, a new study by MIT geologists has suggested.'
According to the researchers, ancient water trickling through Mars' rocks could have triggered a series of chemical reactions, converting CO2 into methane and trapping the carbon in clay minerals for billions of years...
The dominant explanation relies on an interaction between the sun's rays and gases in the atmosphere. Mars lost its protective magnetic field billions of years ago, likely allowing high-energy solar particles to strike the upper atmosphere, kicking molecules off into space, according to NASA... But this might not be the whole story. The researchers focused on a type of clay mineral called smectite, known for its ability to trap carbon. These minerals, abundant on Mars, contain tiny folds that can store carbon molecules for aeons. The study was published in the journal Science Advances.
'There is plenty of evidence for a thick clay layer on the Martian surface. Almost 80 percent of satellite spectra detect these high-surface-area clay minerals on the Martian surface. Clay has been detected in craters as deep as 17 kilometers [10.5 miles],' [lead author Joshua] Murray said... Their model suggested that Mars' surface could contain up to 1.7 bar of CO2 — roughly 80 percent of its early atmospheric volume — sequestered as methane within clay deposits. This methane could still be present today, lying beneath the planet's dry and barren crust. 'We know this process happens, and it is well-documented on Earth. And these rocks and clays exist on Mars,' Oliver Jagoutz, the study's author, said in a statement. 'So, we wanted to try and connect the dots.'

The discovery that Mars' ancient atmosphere could be hidden within its surface clays offers a new perspective on the planet's history and raises intriguing possibilities for future exploration. For example, if the sequestered carbon could be recovered and converted, it could serve as a propellant for future space missions between Earth, Mars and beyond.

'In some ways, Mars' missing atmosphere could be hiding in plain sight,' says the study's lead author — and the article adds that this raises some interesting possibilities.

'For example, if the sequestered carbon could be recovered and converted, it could serve as a propellant for future space missions between Earth, Mars and beyond...'

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