Revisiting timeline that pinpoints when Mars lost its dynamo — Harvard Gazette

“This confirmed that the generally accepted timeline for the Mars magnetic subject can’t be right,” added Fu. “It’s doubtless it lasted not less than 200 million years longer and doubtless even longer.”

The state-of-the-art quantum diamond microscope in Fu’s lab that supported the analysis examined samples from the Allan Hills 84001 meteorite, which had been retrieved from Antarctica in 1984. This tremendous delicate software revealed that iron-sulfide minerals have been strongly magnetized in several instructions billions of years in the past — again when the meteorite was nonetheless on Mars. Very similar to a compass is drawn to the magnetism of Earth’s North Pole, these minerals have been reacting to Mars’ magnetic subject.

These findings construct on information gleaned by NASA’s Mars Ambiance and Unstable Evolution (MAVEN) mission, which orbited the planet starting in 2014 and, amongst different analysis, labored to interpret remaining magnetic alerts emanating from the crust, mentioned Fu.

The info from Steele and Fu’s group additionally reveal that Mars’ magnetic subject doubtless reversed at occasions, a lot as Earth’s does. Whereas these reversals are presently not understood, in the end they might provide some clues about Mars’ core, mentioned Steele. “In the previous couple of 12 months we’ve gotten higher estimates of how large the core is, and discovered that it’s principally, or presumably fully, liquid. Mars may need a stable interior core, but when it does, it’s very small.” Against this, Earth has each a stable interior core and a liquid outer core. “That tells us that a number of the chemistry in Mars’ deep inside is fairly totally different from what it’s on Earth, which has some broader implications for the way the planet was fashioned,” she mentioned.

The researchers stress that a lot continues to be unknown about our planetary neighbor; nonetheless, the findings do permit some hypothesis.

“If the magnetic subject on Mars was just like Earth’s, then maybe it additionally did job of protecting Mars from this energetic photo voltaic wind,” posited Steele. “Then, when the dynamo shut down, that might have been what truly prompted Mars to lose its environment. From that time, the environment might have quickly eroded away … And that then results in the top of water — or liquid water — on Mars’ floor.”

There are counterarguments, together with the suggestion that the magnetic subject might have truly accelerated atmospheric escape, “so a longer-lived dynamo may need even helped Mars lose its water,” mentioned Steele. “That will be actually fascinating since we’re nonetheless undecided how Mars misplaced a lot of its water and environment so shortly.”

On the very least, the discovering “offers a greater foothold for environment evolution fashions to attempt to perceive which processes have been truly driving the local weather change occasion that Mars went by way of.”

“It’s related to understanding of atmospheric loss extra usually,” mentioned Fu. “That is a part of a bigger-picture change within the subject.”

This work was partially funded by the NASA Rising Worlds program.


Gaia Stucky de Quay.

Sediments on Mars.


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