For the last two years the NASA spacecraft Messenger has been orbiting the planet Mercury. Of the eight planets in the solar system, it’s the closest to the Sun. Lacking much in the way of an atmosphere, it experiences unreal temperature differentials that range between minus 200 C during night time to 450 C during the day. As the planet rotates slowly in its orbit, the entire surface experiences this temperature fluctuation every few months or so, which makes for interesting climate conditions on the planet. Only at the poles is there never any direct sunlight, and water ice has been found there.
The other day NASA scientists released a colour enhanced image of the planet (that’s a shot of it above) where the different colours represent different geological formations. Similar in size to the Moon, Mercury apparently has a relatively large iron core for its size. It also has large surface deposits of sulphur and potassium. You can read more in this report from The Independent.