What Is the Great Red Spot of Jupiter?
The “Great Red Spot” of Jupiter is a persistent anticyclonic storm. It is a giant spinning storm of swirling gases in the southern hemisphere of the planet’s atmosphere. It is like a hurricane on Earth, but it is much larger. It is about 17,000 miles (28,000 km) long and 9,000 miles (14,000 km) wide; it is the biggest storm in this solar system.
This reddish eye-shaped storm is about three times the size of the Earth and can easily be seen with a telescope. Winds inside this storm reach speeds of about 270 miles per hour. Like an enormous thunderhead cloud, it towers above the planet’s massive cloud cover. The Great Red Spot has been a prominent feature of Jupiter’s atmosphere for at least 400 years.
It is not known exactly what causes the Great Red Spot’s reddish color. Theories supported by laboratory experiments suppose that the color may be caused by complex organic molecules, red phosphorus, or yet another sulfur compound. The colors we see are the result of chemical reactions occurring in the atmosphere. Its color is actually pink to orange. Its color sometimes fades and its size changes.
At the present time, it seems to be shrinking, but it may well last many hundreds of years more. Nobody knows when the Great Red Spot first appeared on Jupiter, but it has been seen on Jupiter ever since people started looking through telescopes. Jupiter’s Great Red Spot was discovered in 1664 by Robert Hooke.
Part of the reason it lasts so long in comparison with Earth storms (other than the huge difference in scale and the existence of an internal heat source on Jupiter) is that this storm never goes over land; on Earth, hurricanes loses most of their energy and die when they stray over land. The smaller white spots are also giant storms.