Space newsgroups are currently discussing on how astronomers have discovered a storm system on Titan the size of India. It popped up in April 2008 in the moon’s tropics, a latitude belt not known for cloudiness.

The clouds injected what one astronomer called “an explosion of energy” into Titan’s orange-tinted atmosphere, creating more clouds over the moon’s south pole and dense rain storms that the scientists believe must have filled the moon’s dry lake beds and deeply carved stream channels with a liquid that’s nothing at all like water.

In many ways Titan’s climate resembles that of Earth, but instead of a water cycle, Titan has a methane cycle. Clouds, rain and lakes all exist on Titan, but they are all made of methane. In the moon’s frigid climate, any water is frozen into rock-hard ice.

Scientists suspect the storm’s trigger may have been some kind of geologic activity on the moon’s surface, such as a geyser or new mountain range forming. Atmospheric effects may also have set off the storm. Whatever the cause, once the clouds were established they seem to have spread throughout Titan’s atmosphere in waves.