The Great Red Spot
The Great Red Spot is a great anti-cyclonic (high pressure) storm akin to a hurricane on Earth, but it is enormous (three Earths would fit within its boundaries) and it has persisted for at least the 400 years that humans have observed it through telescopes. Since it is anti-cyclonic in Jupiter's Southern hemisphere, the rotation is counterclockwise, with a period of about 6 days. (A hurricane in Earth's Southern hemisphere rotates clockwise because it is a low pressure system.) The clouds associated with the Spot appear to be about 8 km above neighboring cloud tops. The following two figures show a recent Galileo view of the Great Red Spot, and a closeup of the turbulence in its vicinity. The Coriolis effects that are responsible for cyclones and anti-cyclones on Earth are greatly magnified on Jupiter, which has a rotational frequency about 2 1/2 times that of Earth, but this alone would not account for the persistence and size of the Great Red Spot. There are other fe...
