Theory: Catastrophe Created Mars' Moons

The two moons of Mars � Phobos and Deimos � could be the byproducts of a breakup of a huge moon that once circled the red planet, according to a new theory.

The capture of a large Martian satellite may have taken place during or shortly after the formation of the planet, with Phobos and Deimos now the surviving remnants.

Full Story: www.space.com...

I really think they should focus on figuring out where OUR moon came from rather than Mars's.



Phobos and Diemos are basically just really big asteroids anyway, they're REALLY small in comparison to our moon, and they're not even clost to being spherical (especially diemos). Phobos does have one unique feature though... an enormous crater on it's surface (Stickney crater) which measures 12 by 17 miles. The impact must've almost destroyed the only (averaging) 14 mile diameter moon. (remember, it's not really spherical).

I read in ASTRONOMY magazine a couple of years ago (will have to find a link for it somewhere online), that a rather plausible theory for Phobos and/or Deimos was that approximately 1.5-1 billion years ago, Mars had an atmosphere approximately 1/3 to 1/2 of earth normal, complete with liquid water. (Presently Mars has an atmospheric pressure of 1/100 earth normal)

Somewhere around 1.5 and 1 billion years ago, a very large asteroid impact occurred, at a very oblique angle, greater than 45 degrees. The resulting shock wave, almost parrallel to the planet surface, would have ripped most of the atmosphere off the planet. In such a scenario, the impactor could have "skipped" off the surface with enough velocity to attain orbit, (IE, Phobos and/or Deimos).

Surface expression of the impact could have been covered up by a puncture at the impact site into the magmatic mantel, which would have filled the impact crater with magma, creating a "Mare".

Incidentally, this scenario provides explaination for why volcanism on Mars was known to exist in the past, but not currently. Such an impact would have released such a volume of magma as to interrupt the normal internal seismic/tectonic processes.