It is exceedingly frustrating that we can’t go drill into other worlds, and when we try to study other planets like Mars, we have to make do with whatever we can get. Today, that means looking at rocks from Mars that were launched our way during giant impacts and studying the measurements of modern-day missions on and orbiting the red planet. 

Meteorites from Mars contain trapped pockets of gas from the past while missions reveal modern atmospheric ingredients. Remarkably, we find that neon, an easy-to-lose element, has been around on Mars for a long time. Since neon doesn’t stay around, its abiding presence indicates that while individual neon atoms may be escaping, the neon in Mars’s atmosphere is being constantly replenished from somewhere. 

The most likely source is volcanic eruptions, and according to a new paper in Icarus that is led by Hiroyuki Kurokawa, this implies volcanic eruptions as recently as within the past 50,000 years! Further, since Mars still has neon to give off, it must have a lot of neon inside, and that means Mars formed fast and that neon was mixed into Mars’s internal structure before the Sun began to clear out the inner solar system with its winds.

Now, while this explanation is the most exciting and seems the most likely, it is also possible that dust, asteroids, and/or comets carried neon to Mars. To really understand what happened, we need a better understanding of the exact isotope of neon on Mars, and that means we need more rocks. Those being collected by the Mars Perseverance rover may already have the info we need locked away.

More Information

Noble Gas Hints at Mars’s Rapid Formation (Eos)

“Mars’ atmospheric neon suggests volatile-rich primitive mantle,” Hiroyuki Kurokawa et al., 2021 September 4, Icarus