Billions of years ago, Mars hosted rivers and lakes, as well as a thick atmosphere not unlike that of modern-day Earth. But over time, the possibly once-blue planet lost its atmosphere to space, turning it into the cold, dry, inhospitable place we know today.
Scientists really want to learn what Mars ancient atmosphere was like in the past, as it could reveal a lot about what any hypothetical martian life would have been like. And now, according to
a recent paper published in Nature Geoscience, researchers think one of
Mars’ two puny moons could be key to unlocking the history of Mars’ primordial skies.
Phobos: A possible piece of the puzzle
Mars’ moon Phobos orbits the Red Planet 60 times closer than our Moon orbits Earth. And such a tight orbit means it’s entirely feasible that Phobos has been hit by particles shed from Mars over time, leaving clues to the planet’s past atmosphere ingrained in Phobos’ surface.
That’s why, one day over coffee, Andrew Poppe — a research scientists at the Space Science laboratory at the University of California, Berkeley, and co-author of the new study — asked if anyone had considered what Phobos could tell scientists about Mars. Surprisingly, he learned, nobody had ever looked into it before.
The idea of using a moon, like Phobos, as a proxy for a planet’s past isn’t unheard of, though. Earth’s Moon is considered one of the best archives available for the early solar system thanks to its lack of atmosphere, wind, and water.
“What we’ve seen in Apollo samples is that the Moon has been patiently recording individual atoms coming from the Sun and from Earth,” Poppe said in a
press release. “It’s a really cool historical record.”
So, using data from NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, Poppe, along with the study’s lead author, Quentin Nénon, a researcher at the Space Sciences Laboratory at the University of California, Berkeley, looked into the possibility that Phobos held a similar historical record of Mars.