the-actual-universe: PhobosThis image was taken by ESA’s Mars Express spacecraft in 2010 and s

the-actual-universe:

Phobos

This image was taken by ESA’s Mars Express spacecraft in 2010 and shows Phobos, the larger of Mars’s moons, with the smeared surface of Mars in the background. Phobos is believed to be an asteroid captured from the asteroid belt by Mars’s gravity and is one of the darkest moons anywhere in the solar system.

It orbits only 6000 kilometers above Mars’s surface and it is being pulled gradually into the surface by Mars’s gravity. By some estimates, in about 50 million years, it will end up impacting Mars’s surface at a highly oblique angle. One wonders if Phobos is the first “moon” of Mars in the planet’s 4.56 billion year history with this lifestyle; a captured asteroid that orbited for millions of years prior to impact. If any other moon had this trajectory previously, it would simply be a crater today, hard to tell from any of the other ones on the planet’s surface.

-JBB

Image credit: ESA

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