Topic: When worlds collide

[Nemesis]

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The Spitzer Space Telescope has detected signs of an interplanetary smashup, and oh, what a colossal event it was… apparently, 100 light years away around the young star HD 172555, an object the size of the Moon slammed into a planet the size of Mercury!

The best fit to the data suggest that one object was planet-sized and the other Moon-sized, meaning the collision would have been at very high speed — several kilometers per second — and launched an unimaginable amount of material into space. Furthermore, it couldn’t have happened too long ago, or else the material would have dissipated and wouldn’t have been seen. It looks like this was a recent event, then, occurring maybe only a few thousand years ago!