In this image, the colors and contrasts were modified to emphasize the planetтАЩs atmospheric features. The winds in NeptuneтАЩs atmosphere can reach the speed of sound or more. NeptuneтАЩs Great Dark Spot stands out as the most prominent feature on the left. Several features, including the fainter Dark Spot 2 and the South Polar Feature, are locked to the planetтАЩs rotation, which allowed Karkoschka to precisely determine how long a day lasts on Neptune. Erich Karkoschka