The spot, whose main cloud layer is likely ammonia, appears to be an area of upwelling, in which clouds billow up from below. We’re still unsure as to the exact chemistry responsible for the spot’s brick-red color, as many Jovian storms boast a similar shade. Some other storms are white, however.
On Earth, hurricanes grow over oceans and dissipate soon after making landfall. But because Jupiter lacks a surface that slows or confines storms, Jovian winds and hurricanes last for centuries – if not longer. Sometimes Jupiter’s storms merge, combining to form even larger oval features. Bigger storms like the Great Red Spot gobble up smaller neighbors.
Although calling features like the spot “storms” is an accurate way to describe them, they are technically termed anticyclones (cyclones whirl in the other direction). For scientists, a “storm” usually refers to turbulent updrafts of material, which appear less frequently and produce lightning.
See how storms on Earth compare to Great Red Spot.
Click to find out how many Earths can fit inside the Great Red Spot
What is the Great Red Spot?