The Great Dark Spot (also known as GDS-89) is a dark spot on Neptune similar in appearance to Jupiter's Great Red Spot. It was discovered in 1989 by NASA's Voyager 2 probe. Although it appears similar to Jupiter's spot, which is an anticyclonic storm (this is like a hurricane), it is believed that the Great Dark Spot is an atmospheric hole similar to the hole in Earth's ozone layer. view more...