So… yes, Mercury!
NASA just released their new pictures of Mercury. The Messenger (MErcury Surface, Space ENvironment, GEochemistry and Ranging) space craft, launched back in August 2004, got into orbit around Mercury 17th March and has finally sent back its pictures. This is the first time a craft has gotten into orbit around Mercury. Mercury is a weird-ass planet; it is incredibly dense, containing a metallic core. The exact composition is unknown. Up until now, only 45% of the planet has been observed, getting the Messenger probe into orbit around the planet means being able to observe the rest of it. Other interesting quirks include the fact that Mercury, like Earth has a magnetic field (other planets, Venus and Mars do not); the Messenger mission aims, amongst other things, to determine why this is the case.
From a physics point of view, getting a satellite into orbit around Mercury is a bit of a faff because just aiming a spaceship at Mercury would simply lead to the craft being pulled into the sun. To get around this, the Messenger spacecraft performed a couple of flybys of Earth, Venus and Mercury, in order to slow the craft down enough to get it into orbit around Mercury. It’s basically been corkscrewing its way to Mercury:
So yeah – NASA just posted the first photos 😀