Kleopatra and her kids

The entire universe in blog form
March 26 2011 7:00 AM

Kleopatra and her kids

One of my favorite asteroids is Kleopatra: a big, 217 km (135 mile) long main-belt rock that's a wee bit weird. This image may give you a hint as to why:

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It's shaped like a cartoon dog bone! It circles the Sun out past Mars, tumbling end-over-end, and its origins have always been something of a mystery. However, new observations and analysis reveal quite a bit about how this asteroid got its unusual shape. I won't spoil it, but instead simply point you to Emily Lakdawalla's excellent summary of Kleopatra on The Planetary Society blog. It's a tale of collisions, spin, and eventual reconciliation, as many good stories are.

One thing I didn't know is that Kleo has two moons: Alexhelios and Cleoselene. They orbit the asteroid in the plane of the its rotation, and may be cast-offs from the formation of Kleo itself. Read Emily's article for the whole scoop.

Man, the solar system is a cool place. And there's still so much left to see!


Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death from the Skies!