Weather phenomena and systems on other planets are consideration to be similar to those on Earth, but often occur on a much bigger scale or involve different substances to those familiar to Earth dwellers. The Cassini-Huygens mission to Titan, for example, discovered clouds produced from methane or ethane which deposit rain composed of liquid methane and other organic compounds.
Extra-terrestrial weather systems can be extremely stable; one of the most famed landmarks in the solar system, Jupiter's Great Red Spot is an anticyclonic storm known to have existed for at least 300 years. On other gas giants, the lack of a surface allows the wind to reach huge speeds: gusts of up to 400 meters per second have been measured on the planet Neptune. This has created a puzzle for planetary scientists: The weather is created by the differential action of the Sun's energy on different places and the amount of energy received by Neptune is very, very small, relative to the Earth, yet the strength and magnitude of weather phenomena on Neptune is far, far greater than on Earth. This mystery is still to be solved.