Meteorite from Mercury

This just landed in my inbox from NPR:

http://www.npr.org/2013/04/11/176714430/origin-of-meteorite-is-a-puzzle-to-scientists?ft=3&f=122101520&sc=nl&cc=sh-20130413

It's about a meteorite that could have possibly come from mercury... although it turns out it probably didn't. 

I guess it has a similar chemical makeup as Mercury. It's very low in iron which was one of the things that ruled out it coming from Mars or simply being an Earth rock.

Furthermore, it turns out that this rock has the same magnetic field as Mercury. I'm not exactly what that means but it seems pretty far out. I should do some reading on magnetic fields. 

The one chink in this theory is that the meteorite is extremely old. So old that it predates Mercury being solid enough to create such rocks. The current theory is that it actually comes from the asteroid belt.

Either way this is apparently a very fascinating meteorite. There's a great slide show of a bunch of other meteorites on the page linked above. It includes a one from Mars, one from the moon, and one that's actually the oldest rock ever found. It was formed in the gas cloud that used to surround the sun!

It never occurred to me that meteorites could be from other planets. I always assumed they where just free floating rocks in space. Now that we're learning about how all this works it makes much more sense that more relatively large rocks would be formed on other planets than that they would form on their own in space.