Jupiter Has the Shortest Day of Any Planet

The biggest planet is also the quickest spinner. NASA states that Jupiter has the shortest day in the solar system, taking about 9.9 hours to spin around once on its axis. That is less than half an Earth day, on a planet so large that, in NASA’s words, 1,000 Earths could fit inside if it were a hollow shell. What a visitor would see spinning past is weather. NASA describes Jupiter’s signature stripes and swirls as cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. The dark orange stripes are called belts and the lighter bands are called zones, and they flow east and west in opposite directions.