NASA launched the Messenger space probe back in August of 2004 and now Messenger has arrived closer to its destination and has started taking images of the planet Mercury.
Thousands of images will be taken and provided January 30, 2008. Scientists hope to learn more about Mercury including the composition of Mercury.
Earth is about 3x the distance from the Sun as Mercury is so the Sun facing part of Mercury is much hotter, however Mercury's slow rotation makes the side facing away from the Sun very cold. Mercury is smaller than Earth and much more dense. It is believed that more than half of Mercury is made of iron ore.