Storm - Extraterrestrial Storms

Extraterrestrial Storms

Storms are not unique to Earth; other planetary bodies with a sufficient atmosphere (gas giants in particular) also undergo stormy weather. A famous example is the Great Red Spot on Jupiter. Though technically an anticyclone with greater than hurricane wind speeds, it is larger than the earth and has been raging for at least 340 years, having first been observed by astronomer Galileo Galilei. Neptune also had its own lesser known Great Dark Spot.

In September 1994 Hubble telescope using Wide Field Planetary Camera 2 imaged the storms on Saturn, generated by upwelling of warmer air, similar to a terrestrial thunderhead. The east-west extent of the same-year storm was equal to the diameter of Earth. The storm was observed earlier in September 1990 and acquired the name Dragon Storm.

The dust storms of Mars are variable in size, but can often cover the entire planet. They tend to occur when Mars is closest to the Sun, and have been shown to increase the global temperature.

One particularly large extraterrestrial storm was exhaustively studied up close simply due to coincidental timing. When the first spacecraft to be successfully put into orbit around another planet, Mariner 9, arrived and successfully orbited Mars on 14 November 1971, planetary scientists were surprised to find the atmosphere was thick with "a planet-wide robe of dust, the largest storm ever observed." The surface was totally obscured. Mariner 9's computer was reprogrammed from Earth to delay imaging of the surface for a couple of months until the dust settled. However, the surface-obscured images contributed much to the collection of Mars atmospheric and planetary surface science.

Two known extrasolar planets have known to be possess storms: HD 209458 b and HD 80606 b. The former's storm was discovered on June 23, 2010 and measured at 6,200 km/h, while the latter has shockwave storms whipping around the planet in 12 hours.