Mercury Isn’t Alone in Orbit, and Scientists Don’t Know Why

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https://eos.org/articles/mercury-isnt-alone-in-orbit-and-scientists-dont-know-why

By Jure Japelj, Eos/AGU. 

Excerpt: A cloud of dust traces the innermost planet’s orbital path. By all accounts, it shouldn’t be there. ...In a new study published in the Planetary Science Journal, scientists tried to trace the genesis of Mercury’s dust. And although they still don’t know how this improbable cloud formed, they do know that it probably has a different origin story than the one escorting our own planet. ...Earth’s dust ring formed from the immense cloud of dust, called a zodiacal or interplanetary dust cloud, that pervades the space between planets. ...Earth and Venus are massive enough to stall migrating dust, but Mercury is not. That close to the Sun, phenomena including solar winds, solar light, and strong magnetic fields should, quite literally, kick the dust up, and Mercury isn’t large enough to trap the celestial debris in its gravitational pull. ...Using data from NASA’s MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) spacecraft, the team identified two craters larger than 40 kilometers in diameter on Mercury’s surface that might be younger than 50 million years. Perhaps collateral debris from these strikes billowed out into space....

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