Great White Spot
periodic storms on Saturn
The Great White Spot, also known as Great White Oval (named by analogy to Jupiter's Great Red Spot) is a series of periodic storms on the planet Saturn that are large enough to be visible from Earth by telescope by their characteristic white appearance. The spots can be several thousands of kilometers wide.
The Cassini orbiter was able to track the 2010–11 instance of the storm, also known as the Northern Electrostatic Disturbance, because of an increase in radio and plasma interference, or the Great Springtime Storm.
Cassini data has revealed a loss of acetylene in the white clouds, an increase of phosphine, and an unusual temperature drop in the center of the storm. After the visible aspects of the storm subsided, in 2012, a "belch" of heat and ethylene was emitted from two hotspots that merged.
Occurrence
The phenomenon is somewhat periodic at 28.5-year intervals, when Saturn's northern hemisphere tilts most toward the Sun. Usually this is during the solar longitude of around 90-180°, only the 2010 GWS was ahead of its time shortly after equinox. The following is a list of recorded sightings. Six events are recognized as Great White Spots.
Equatorial (1.8°N to 9.8°N)
1876 – Observed by Asaph Hall.
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This entry incorporates text from “Great White Spot” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.