As far as we know, we’re the only habitable planet in the Solar System. We have yet to discover life elsewhere, but Mars – even today – is a pretty good bet. It’s got salty, liquid water on its surface, and although its atmosphere is thin and insubstantial, microbial life could lurk within the sediments, where it’s shielded from incoming solar radiation.
However, as researchers are continuously discovering, Mars was likely once far more habitable. Recent data from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission revealed that its once-thick atmosphere, held in place by a wavering magnetosphere, was stripped away by major solar storms. Now, another NASA mission called SOFIA – the Stratospheric Observatory for Infrared Astronomy – has found that there are traces of atomic oxygen still lingering in the gaseous envelope that surrounds the Red Planet.
Atomic oxygen was first detected in the Martian atmosphere 40 years ago by the Viking and Mariner missions, but it hasn’t been picked up since. “Atomic oxygen in the Martian atmosphere is notoriously difficult to measure,” said Pamela Marcum, SOFIA project scientist, in a statement.
SOFIA, a flying observatory attached to a Boeing 747 S P, looks at the infrared part of the electromagnetic spectrum. It’s designed to peer into the hearts of stars, the complex clouds of planetary nebulae, and the atmospheres of planets – both outside the Solar System and those right next door to us.