The Great Dark Spot is thought to represent a hole in the methane cloud deck of Neptune. The spot was observed at different times with different sizes and shapes. ... Unlike the clouds on Earth, however, which are composed of crystals of ice, Neptune's cirrus clouds are made up of crystals of frozen methane.The Great Dark Spot was a huge spinning storm in the southern atmosphere of Neptune which was about the size of the entire Earth. Winds in this storm were measured at speeds of up to 1,500 miles per hour. These were the strongest winds ever recorded on any planet in the solar system! The Great Dark Spot was first discovered when the Voyager 2 spacecraft flew by Neptune in 1989. When the Hubble Space Telescope looked at Neptune in 1994, the Great Dark Spot was gone and a different dark spot had appeared in the northern atmosphere of Neptune. Pick out some you need
