NEPTUNE: SUPERSONIC WINDS Winds on Neptune travel faster than the speed of sound. Neptune, the eighth and farthest planet from the sun, has the strongest winds in the solar system. At high altitudes speeds can exceed 1,100 mph. That is 1.5 times faster than the speed of sound. In 1989, NASA's Voyager 2 spacecraft made the first and only close-up observations of Neptune. Detailed images taken by the spacecraft revealed bright, white clouds and two colossal storms whipping around the planet's atmo