Skip to comments.Was Mercury a ‘hit-and-run’ planet?
Posted on 01/25/2006 10:26:47 PM PST by Swordmaker
Computer modeling suggests that collision affected its formation
New computer modeling shows that the planet Mercury might have been formed in a hit-and-run collision that stripped off its outer layers.
Astronomers have long assumed that collisions played a huge role in planet formation. The early solar system would have been loaded with dust that became rock that became planets, the thinking goes. Computer models generally have objects sticking together to make ever-larger objects or in large crashes, two objects might become gravitationally bound.
In the new scenario, a glancing blow would dramatically alter the smaller object, even disintegrating it into pieces that could be some of the space rocks that land on Earth to this day.
. . .
"Imagine two planets colliding, one half as big as the other, at a typical impact angle of 45 degrees. About half of the smaller planet doesn't really intersect the larger planet, while the other half is stopped dead in its tracks," Asphaug said. "So there is enormous shearing going on, and then you've got incredibly powerful tidal forces acting at close distances. The combination works to pull the smaller planet apart even as it's leaving, so in the most severe cases the impactor loses a large fraction of its mantle, not to mention its atmosphere and crust."
(Excerpt) Read more at msnbc.msn.com ...
Mosaic of photos of Mercury
Thanks SM for posting it! I guess I didn't go to be after all (wound up working until 1 AM). Off I go now...
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Mercury's formation impact splattered Earth with materialNew computer simulations of Mercuryâs formation show the fate of material blasted out into space when a large proto-planet collided with a giant asteroid 4.5 billion years ago. The simulations, which track the material over several million years, shed light on why Mercury is denser than expected and show that some of the ejected material would have found its way to the Earth and Venus... "Mercury is an unusually dense planet, which suggests that it contains far more metal than would be expected for a planet of its size. We think that Mercury was created from a larger parent body that was involved in a catastrophic collision, but until these simulations we were not sure why so little of the planetâs outer layers were reaccreted following the impact,â said Dr Jonti Horner, who is presenting results at the Royal Astronomical Societyâs National Astronomy Meeting on 5th April.
Royal Astronomical Society
April 05, 2006
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