Mercury: Not Actually Made of Mercury

Except in the sense that people call dirt "Earth" sometimes. I suppose if you were on Venus you would call the soil "Venus." Anyway, this is all just an excuse for me to show some gratuitous Mercury shots. The MESSENGER Mission just got to Mercury and photographed it's barren, hostile, sunburnt surface in great detail. This is the first mission to the (now) littlist planet since the Mariner 10 mission in the seventies. I spent a lot of time pouring over glossy picture books about the planets when I was younger and I think I got the impression that Mercury was yellowish, even though I knew that it wasn't. Futurama got that idea too. And, amazingly, the NASA art staff got it too!

So for Mercury-huggers this mission is a bonanza. Surface composition, magnetic field, the core (which is liquid now apparently), and these "dazzling" photos, which are probably just doctored pictures of the moon.

The photo below was taken near the closest approach and shows a section of Mercury 500km across where smallest craters are only 1km or so. Seriously though, this is just the moon.

[Official Messenger Site, Photo 1, Photo 2, and the Planetary Society has an excellent article]