Scientists have been hunting for evidence of water on Mars ever since we started looking at the Red Planet through telescopes. But Mars does have water, and lots of it; solid water in the form of ice locked up in its polar caps and buried under its surface. And, if observations made by ESA’s Mars Express are indicative of similar processes seen on Earth, these ancient hills may also hold hidden deposits of underground ice.
It’s been thought for some time that Saturn’s largest moon Titan has a complex internal structure consisting of multiple layers of ice and liquid water. At one point it was even suggested that there are water ice “cryovolcanoes” on Titan, where watery slush oozes to the surface and freezes solid in the moon’s 270-degree-below temperatures, in very much the same way that liquid rock does on Earth. Now, thanks to recent gravitational observations by Cassini (and who else?) some researchers think that Titan’s icy shell may be much thicker in places than once thought, making the existence of ice volcanoes and Earthlike plate tectonics much less likely.
Although surface temperatures on Titan are cold enough that methane can exist as a liquid, filling lakes and flowing in streams, it may sometimes get so cold that even the liquid methane and ethane freezes, forming floes and icebergs of frozen hydrocarbons. This Titanic revelation was announced today during the 221st American Astronomical Society meeting in Long Beach, CA.
Who says Mercury’s too hot to be really cool? Even three times closer to the Sun than we are, lacking atmosphere and with scorching daytime temperatures of 425 ºC (800 ºF), Mercury still has places more than cold enough to hide ice. This is the most recent announcement from the MESSENGER mission team: (very nearly) confirmed ice on the first rock from the Sun!
Although made mostly of ice and rock, Saturn’s moon Dione (pronounced DEE-oh-nee) does have some color to it — although mostly chilly hues of steel blue, as seen in this color-composite made from raw images acquired by Cassini on July 23.