Nearby, Recent Interplanetary Collision Inferred

The Bad Astronomer writes about a new discovery by the Spitzer Space Telescope, which detected signs of an interplanetary smashup only 100 light-years from here, and only a few thousand years ago. There's a NASA-produced animation of the collision between a Mercury-sized planet and a moon-sized impactor. The collision's aftermath was detected by the presence of what are essentially glass shards in orbit around the star. Here's NASA's writeup.

Comments

Neat video, but not very accurate

[olsmeister]

the guy posting the blog states: "the shock wave ring travels around the planet as shown, but when the ring converges on the point opposite the collision point, there would be a huge explosion and a vast plume of material launched into space. No one ever puts that in their animations"

I thought the same thing when I watched the video - there would be a godawful explosion at the antipode

Re:Neat video, but not very accurate

[JuzzFunky]

It is interesting that the animation shows a direct hit head on collision rather than a glancing blow. Most of matter from the planet and impactor seems to combine into a single mass. Would a glancing blow that shatters the impactor result in more debris?

Re:Neat video, but not very accurate

[pintpusher]

I immediately wondered if there were any such antipodal geology evident on earth. A quick google turned up this presentation which is pretty darn interesting. IANAGeologist, and can't speak to the accuracy of the claims, but it's still darn cool!