The Windy Planet

Neptune as seen by NASA's Hubble Space Telescope. This image is one of a series of pictures that has been made into a movie loop showing a full rotation of the eighth planet from the sun. Neptune's powerful winds whip around its equator at an estimated 900 mph. The cause of Neptune's blustery weather is an enigma, said Lawrence Sromovsky, the University of Wisconsin-Madison Space Science and Engineering Center scientist who made the observations. On Earth, winds are driven by the sun's energy, which heats the atmosphere and oceans. On planets farther from the sun, like Neptune where the sun is 900 times dimmer, winds should be weaker. But Neptune's weather is among the most dynamic in the solar system with changes occurring on time scales ranging from minutes to decades.