NASA's Messenger has found very strong indications of frozen water in Mercury. But how can there be frozen water in a hell like Mercury, the closest planet to the sun, boiling at 400C?
The answer is something called cold traps, areas of the surface of Mercury that are constantly cold because of the planet's position in relation to the sun. This position makes some craters to have a permanent shadow, where the temperatures have remained low enough to retain the frozen water that was originally in the planet. The yellow parts in the image line up perfectly with those permanently shadowed parts.
The discovery — which is being published in Science — was made by a team of scientists from Johns Hopkins University Applied Physics Laboratory. They superimposed the Mercury surface data obtained by the Arecibo Observatory in 2011 — which indicated the presence of water much to the surprise and disbelief of scientists — with the precise topographical information obtained by Messenger's Mercury Dual Imaging System (MDIS). The result is what you can see here, and clear indication that, indeed, water most probably exists in hell.
The bad news: we can't say "when hell freezes over" anymore. [Messenger]