Radical. That's the word on the changes Neptune has undergone since 1989, according to Heidi Hammel of the Massachusetts Institute of Technology. Recent images from the Hubble Space Telescope reveal that a new spot has emerged in the northern hemisphere of this aquamarine-colored gaseous planet(see photo inset). The new spot, believed to be a huge storm system, is a near mirror-image of a previous spot in the southern hemisphere, which was discovered by Voyager 2 in a 1989 fly-by. Last June, Hubble images revealed that this first great dark spot had disappeared.