Jupiter's Great Red Spot - A Super Storm

False-color image of Jupiter's Great Red Spot. (Voyager 1)The most prominent and well-known feature of the planet Jupiter is the Great Red Spot. It is not a surface feature, as the hard core of Jupiter lies at the bottom of an atmosphere that is thousands of miles deep. So what can explain something as seemingly permanent as the Great Red Spot?

The Spot is actually a spinning storm in the Southern hemisphere of Jupiter, like a hurricane here on Earth, with very high winds, but thousands of times larger. In fact, three Earths wouldn't cover the Giant Red Spot completely. The comparison to a hurricane is not exactly accurate. The Spot is a high-pressure system, that is several miles (kms) higher than the clouds around it, while a hurricane is a low-pressure system that spins in the opposite direction.

The Spot pre-dates at least the time of Galileo in the early 1600s, when humans first began using telescopes to observe the heavens. That means this particular storm has been raging continuously for over 400 years. Certainly the composition of Jupiter's atmosphere, the planet's density, mass and volume all contribute to the storm's longevity. But what about its color? Although Jupiter's atmosphere is made up mostly of hydrogen and helium, there is speculation that the Spot's noticeable red color is due to a higher concentration of phosphorus within the storm.

About the Author

Gene Mascoli, JD

Gene MascoliGene Mascoli is a founder and publisher of He holds a J.D. degree from the University of Santa Clara and a B.A. in English. In 1997 Gene launched, an online science education portal where he brought together his love of writing with his interest in the sciences. Gene collaborated with David Gamon on the popular digital book “The Internet Guide to NASA on the Net” and has also produced two popular science CD-ROMs on astronomy and space science.