Rainbows on Titan

Saturn's moon Titan is wet, according to the ESA's Huygens probe, but Titan's "water" is not like Earth's.
When the European Space Agency's Huygens probe visited Saturn's moon Titan in January 2005, the probe parachuted through humid clouds. It photographed river channels and beaches and things that look like islands. Finally, descending through swirling fog, Huygens landed in mud.
To make a long story short, Titan is wet.
Christian Huygens wouldn't have been a bit surprised. In 1698, three hundred years before the Huygens probe left Earth, the Dutch astronomer wrote these words:
"Since 'tis certain that Earth and Jupiter have their Water and Clouds, there is no reason why the other Planets should be without them. I can't say that they are exactly of the same nature with our Water; but that they should be liquid their use requires, as their beauty does that they be clear. This Water of ours, in Jupiter or Saturn, would be frozen up instantly by reason of the vast distance of the Sun. Every Planet therefore must have its own Waters of such a temper not liable to Frost."