Jupiter has the Great Red Spot, a giant storm in its atmosphere. The feature is a persistent anticyclonic storm located in Jupiter’s southern hemisphere.
The Great Red Spot is wider than Earth, although its size has changed over time and it has gradually contracted since modern measurements began. Its reddish color varies, and scientists have proposed several explanations involving atmospheric chemistry, ultraviolet light, and material brought upward from deeper layers.
Astronomers have observed the storm for at least several centuries. Giovanni Domenico Cassini reported a spot on Jupiter in the seventeenth century, but researchers cannot prove that his observation was the same continuous storm seen today. The first unambiguous modern observations date from the nineteenth century.
Jupiter’s rapid rotation and powerful atmospheric bands help organize long-lived vortices. The planet’s atmosphere is mostly hydrogen and helium, with clouds of ammonia and other compounds. NASA’s Juno spacecraft has studied Jupiter’s polar regions, atmosphere, magnetic field, and the Great Red Spot since entering orbit in 2016.