Astronomy
Properties of Jupiter's Great Red Spot Storm
Quick fact
At its current size, the Great Red Spot is roughly as wide as one and a half Earths, yet it is a single storm that has raged for at least 150 years—and likely much longer—making it the largest known storm in the solar system.
Why this is interesting
You have probably seen Jupiter's Great Red Spot in photos, but have you ever wondered why a storm there is bigger than Earth and has lasted for centuries? What keeps that gigantic oval spinning?
Read the full explanation
Understanding Properties of Jupiter's Great Red Spot Storm
Imagine taking the fiercest ocean whirlpool you know and scaling it up until it could swallow whole continents. That's Jupiter's Great Red Spot. More formally, it is an anticyclone—a weather system with high pressure at its center. On Jupiter, winds move in opposite directions along parallel bands, and the Great Red Spot sits between two of these jet streams. The storm spins counterclockwise (in Jupiter's southern hemisphere) and rises above the surrounding cloud deck. Its famous reddish color likely comes from trace chemicals brought up from deeper in the atmosphere and altered by sunlight. The spot is enormous—more than any storm on Earth—but it is also an extremely stable structure, maintaining its shape for decades while slowly drifting westward.
A deeper explanation
Why is the Great Red Spot so persistent? The key is Jupiter's rapid rotation and its deep, turbulent atmosphere. Jupiter spins once every 10 hours, which creates strong westward/eastward jet streams. Two opposing jets trap the vortex between them, acting like a corridor that prevents the storm from breaking apart. Because the spot is a high-pressure anticyclone, it rotates in the opposite direction of the Coriolis effect that would spin up a low-pressure storm on Earth—yet the enormous rotation of the planet provides a stabilizing force. Scientists believe the spot is not just a surface cloud pattern but a deep columnar vortex that extends many kilometers down into Jupiter's atmosphere. It has been shrinking for decades, but it still demonstrates how large, long-lived vortices can form in a gas giant. Studying it helps scientists understand not only Jupiter's weather, but also the general physics of rotating fluids—a principle that applies to Earth's hurricanes, ocean currents, and the atmospheres of exoplanets.