Metal in Mars atmosphere, NASA MAVEN spacecraft detects electrically charged atoms around red planet

NASA’s MAVEN (Mars Atmosphere and Volatile Evolution Mission) spacecraft has detected electrically charged metal atoms high in the atmosphere of the red planet. The new data can reveal previously invisible activity found in the mysterious electrically charged ionosphere of Mars.

NASA’s MAVEN spacecraft is studying the upper atmosphere of Mars to know how the red planet lost most of its air, transforming from a world that could have supported life billions of years ago into a cold desert planet that it is today.

According to researchers, understanding ionospheric activity may throw some light on how the Mars atmosphere is lost to space, researchers said.

“MAVEN has made the first direct detection of the permanent presence of metal ions in the ionosphere of a planet other than Earth,” said Joseph Grebowsky of NASA’s Goddard Space Flight Centre in the US.

“Because metallic ions have long lifetimes and are transported far from their region of origin by neutral winds and electric fields, they can be used to infer motion in the ionosphere, similar to the way we use a lofted leaf to reveal which way the wind is blowing,” said Grebowsky.

A constant rain of tiny meteoroids onto Mars gave birth to the metal.

When a high-speed meteoroid hits the atmosphere of Mars, it evaporates. In the vapour trail, other charged atoms and molecules in the ionosphere tear away the electrons of metal atoms, transforming them into electrically charged ions.

MAVEN has detected iron, magnesium, and sodium ions in the upper atmosphere of the red planet over the last two years using its Neutral Gas and Ion Mass Spectrometer instrument, giving the team confidence that the metal ions are a permanent feature.

“We detected metal ions associated with the close passage of Comet Siding Spring in 2014, but that was a unique event and it didn’t tell us about the long-term presence of the ions,” said Grebowsky.

According to the team, the interplanetary dust that causes the meteor showers is common throughout our solar system, so it is likely that all solar system planets and moons with substantial atmospheres have metal ions.

Metal ion layers high in the atmosphere above Earth have been detected by sounding rockets, radar and satellite measurements. There has also been indirect evidence for metal ions above other planets in our solar system.

When spacecraft are exploring these worlds from orbit, sometimes their radio signals pass through the planet’s atmosphere on the way to Earth, and sometimes portions of the signal have been blocked.

This has been interpreted as interference from electrons in the ionosphere, some of which are thought to be associated with metal ions.

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However, long-term direct detection of the metal ions by MAVEN is the first conclusive evidence that these ions exist on another planet and that they are a permanent feature there. The research was published in the journal Geophysical Research Letters. 

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(With inputs from PTI)