Mars’s atmosphere harbours a layer of electrically charged metal atoms, and they’re not behaving as expected.
NASA’s MAVEN (Mars Atmosphere and Volatile Emission) spacecraft found layers of atmospheric metal ions that defy models based loosely on Earth’s atmosphere.
“Mars is giving us observations both like and unlike Earth, and that’s very exciting,” says Joseph Grebowsky at the NASA Goddard Space Flight Center in Greenbelt, Maryland, head of the team that found these Martian metals.
The space between planets is full of metallic dust and rocks. As they are drawn into a planet’s atmosphere, they burn up, leaving behind metal particles like iron and magnesium. On Earth, the behaviour of those particles is mostly controlled by the planet’s strong magnetic field. They use magnetic fields as a sort of highway, and stream along the magnetic field lines to form thin layers throughout the atmosphere.
But Mars has no such field. The planet does have small regions with weak magnetic fields in its southern hemisphere, but without a global field like Earth’s, it should not be able to form the layers that MAVEN sees.
“Something is causing these layers – something is pushing them around – but we don’t know what,” says Grebowsky. Mars’s nubs of magnetic field certainly play a part, and winds through the atmosphere probably do as well, but the exact mechanism must be different from the one at work on Earth.
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