What Is the Wind Speed on Neptune?

History

• Neptune was only discovered in the early 1800s. The identity of the first astronomer to actually find Neptune is still under debate. Until then, it was thought to be just another star in the sky. It could not be determined if Neptune had an atmosphere or winds. Both of these were discovered by the NASA spacecraft Voyager 2, which took extensive data readings in 1989. The Hubble Space Telescope managed to get images of Neptune's storms in 1994. More information about Neptune's atmosphere was obtained through photos captured from the Keck II telescope at Hawaii's Keck Observatory in 2000.

How Neptune's Winds Were Clocked

• No satellite has gone through Neptune's atmosphere to obtain wind speed information. Wind speed was determined by NASA scientists looking at how quickly clouds traveled across the surface of the planet, on the assumption that the clouds are pushed along by the wind. Other determining factors include how heavy the air pressure is and the estimated temperature of that area of the planet.

Neptune's Atmosphere

• Neptune is a gas giant, so even though it is four times the size of the Earth, most of it is made up of gas. The outer atmospheric layer is thought to be mostly helium, some hydrogen and traces of methane. Some of this methane may be frozen. It's the methane that gives Neptune its blue hue, because it absorbs the color red. It is guessed that the lower atmosphere layers (troposphere and stratosphere) are made up of ammonia, hydrogen sulfide, hydrogen cyanide and carbon monoxide. It is unknown if water or previously undiscovered chemicals exist on Neptune.

Neptune's Storms

• Neptune has two main storm systems that are similar to the Great Red Spot storm system on Jupiter (another gas giant). The biggest is called the Great Dark Spot, thought to be 13,000 by 6,000 kilometers (about eight by three miles). It's a dark blue in color, hence its name. The second storm, the Scooter, makes a white spot on Neptune's southern half and circumnavigates the planet about every 16 hours. It is unknown how old these storms are or when they will die out.

Significance

• The possibility of life on Neptune is practically nil partially because of the atmosphere but mostly due to the wind speeds reached. The possibility of even landing a small unmanned craft on Neptune is also doubtful because of the wind speeds, though the Great Dark Spot and the Scooter do not travel over the entire planet.