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Chippy Family

December 10, 2010

Most of us don't think of a trail of ice chips as a family, but astronomers do. Over the last few years, they've been studying a trail of ice chips that's related to Haumea, one of four "dwarf planets" beyond the orbit of Neptune.

Haumea is shaped like a long potato, with an average diameter of about 800 miles, give or take a hundred -- a bit more than half the size of Pluto, the most famous dwarf planet. It spins in a hurry -- once every four hours. And it has two known moons.

About 10 smaller objects follow similar orbits around the Sun. And their surfaces have a similar composition to the surface of Haumea -- pure water.

That means the smaller objects are probably bits of debris chipped off in a collision between Haumea and another body.

A recent study says that Haumea itself probably began as a "rubble pile" -- a clump of smaller chunks of rock and ice. They formed an elongated shape like a thick loaf of french bread.

Another large body then hit Haumea. This weakened it enough that it eventually split apart. The larger fragment is what we see today as Haumea. The other was later shattered by another impact. Haumea held on to some of the fragments, which are its present-day moons. But the others were kicked away from the small world, entering their own orbits around the Sun -- forming an extended family.


Script by Damond Benningfield, Copyright 2010


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