If you look at a picture of our solar system’s biggest planet, your eye goes straight to it. That angry, swirling crimson blemish. People often ask what is the storm on Jupiter called, and the answer is the Great Red Spot. It's iconic. Honestly, it’s arguably the most famous feature in the entire solar system outside of Saturn's rings. But calling it just a "storm" feels like calling the Pacific Ocean a "puddle."
It’s huge. It’s ancient. It’s weirdly persistent.
While Earthly hurricanes usually fizzle out once they hit land or cold water, the Great Red Spot has been spinning for centuries. We have records from astronomers in the 1800s—and potentially as far back as the 1600s with Giovanni Cassini—describing a "permanent spot" on Jupiter. Imagine a storm that started before the United States was even a country and is still raining down hell today. That is the scale we are dealing with.
The Physics of the Great Red Spot
So, why hasn't it stopped? On Earth, storms lose energy because they create friction with the ground. Jupiter is a gas giant. There is no ground. It’s just layers of hydrogen and helium that get denser and hotter the deeper you go. Without a solid surface to grind against, a vortex can just... keep going.
The Great Red Spot is technically an anticyclone. On Earth, most of our destructive storms are low-pressure systems (cyclones). This thing is a high-pressure system. It rotates counterclockwise in Jupiter’s southern hemisphere, completing a full bridge-to-bridge rotation every six Earth days or so.
It's sandwiched between two powerful jet streams that move in opposite directions. Think of it like a ball bearing caught between two conveyor belts moving at different speeds. The northern belt pushes one way, the southern belt pushes the other, and the Great Red Spot just rolls in the middle, trapped in its own lane. This atmospheric "conveyor belt" is exactly what keeps it fueled. It sucks up smaller storms and eddies, devouring them to maintain its own momentum.
What’s with the color?
Nobody actually knows for sure why it’s red. That’s the dirty little secret of planetary science. If you took a scoop of Jupiter's upper atmosphere, it’s mostly colorless ammonia ice. Scientists like Dr. Amy Simon from NASA’s Goddard Space Flight Center have proposed that the color comes from "photochemical" reactions. Basically, solar radiation hits chemicals like ammonium hydrosulfide or phosphine that have been dredged up from deep inside the planet.
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Think of it like a cosmic sunburn. When these chemicals are exposed to UV light from the sun, they turn a deep, rusty red. The higher the storm reaches into the atmosphere, the more sun it gets, and the redder it looks. If it sinks, it fades to a pale salmon or even white.
Is the Great Red Spot actually disappearing?
Here is the thing: the storm is shrinking.
In the late 1800s, the Great Red Spot was massive. It was estimated to be about 41,000 kilometers wide. You could have fit three Earths inside it side-by-side. When the Voyager 1 and 2 spacecraft flew by in 1979, it had already shrunk to about 23,000 kilometers.
Today? It’s roughly 16,000 kilometers wide. Now, that’s still wider than Earth (which is about 12,742 km), but it’s definitely "dieting." It's also becoming more circular rather than oval-shaped.
Some astronomers have speculated it might vanish within our lifetime. In 2019, observers saw "flakes" or "blades" of red clouds peeling off the main storm. It looked like the Great Red Spot was literally unraveling. However, data from the Juno spacecraft suggested these were just superficial interactions with other smaller storms. The deep "roots" of the storm—the part that actually drives the engine—seem to be intact.
How deep does the rabbit hole go?
For a long time, we thought this was just a surface-level weather event. We were wrong. NASA’s Juno mission, which has been orbiting Jupiter since 2016, used a Microwave Radiometer to peer beneath the clouds.
It turns out the Great Red Spot is incredibly deep. It extends about 300 to 500 kilometers down into the planet. To put that in perspective, the International Space Station orbits Earth at about 400 kilometers high. The storm is as deep as the ISS is high.
The roots are warmer than the top. This temperature difference is what fuels the vertical winds. It’s a massive heat engine. Interestingly, even though it's shrinking in width, some evidence suggests it might actually be getting taller. As it gets squeezed by the surrounding jet streams, it stretches upward, much like a lump of clay being squeezed in your hand.
Why the "What is the storm on Jupiter called" question matters for Earth
It’s easy to look at Jupiter and think it’s just a cool screensaver. But studying the Great Red Spot is basically "Fluid Dynamics 101" on a massive scale. By understanding how Jupiter’s atmosphere works without the "interference" of landmasses or oceans, meteorologists can build better models for Earth’s weather.
Jupiter is essentially a laboratory for extreme physics. The winds at the edge of the spot can reach 430 to 680 kilometers per hour. That’s double the speed of the strongest Category 5 hurricanes on Earth. If we can figure out what keeps that engine running for 300 years, we might better understand the long-term stability of high-pressure systems on our own planet, which often cause heatwaves and droughts.
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Other storms you should know about
The Great Red Spot isn't the only show in town. Jupiter is a violent place.
- Oval BA (Red Junior): This storm formed in 2000 when three smaller white spots collided. It eventually turned red, just like its big brother, proving that the red color is likely a result of height and sun exposure.
- The Polar Cyclones: When Juno flew over the poles, it found something bizarre. At the North Pole, there are eight huge cyclones surrounding a central one. At the South Pole, there are six. They stay in these perfect geometric patterns—polygons of storms—and they don’t merge. We still don’t fully understand why they stay locked in that formation.
- The Great Cold Spot: Discovered more recently in the upper atmosphere, this is a localized dark spot that is much cooler than its surroundings, likely caused by the planet’s powerful auroras.
What to watch for in the coming years
If you have a decent backyard telescope, you can actually see the Great Red Spot yourself. It looks like a tiny, pale brick-colored smudge against the white and tan stripes of Jupiter’s cloud belts. Because Jupiter rotates so fast (a "day" is only 10 hours), you have to time your viewing for when the spot is facing Earth.
Astronomers are currently keeping a close eye on the "flaking" events. Every time a smaller storm hits the Great Red Spot, it causes a stir. Some think these collisions are actually what keeps the spot alive by injecting fresh angular momentum. Others think they are slowly chipping away at its structure.
Actionable insights for space enthusiasts
If you want to stay updated on the status of Jupiter’s massive storm, don’t just wait for NASA press releases. The community of amateur planetary photographers is often the first to spot changes.
- Check the JunoCam Image Gallery: NASA uploads raw data from the Juno mission directly to the public. You can see the latest high-resolution "perijove" (close approach) photos before they are even processed by the media.
- Use a Transit App: If you own a telescope, use a "Jupiter Transit" calculator or an app like SkySafari. It will tell you exactly when the Great Red Spot will be visible from your specific location.
- Follow the "Flaking" News: Keep an eye on reports from the Hubble Space Telescope’s OPAL program (Outer Planet Atmospheres Legacy). They release yearly "maps" of Jupiter that show exactly how much the spot has shrunk since the year before.
Jupiter’s atmosphere is a chaotic, beautiful mess. The Great Red Spot is the anchor of that chaos. Whether it’s a permanent fixture of the solar system or a dying giant, it remains the ultimate reminder of just how small and quiet Earth’s weather really is.
Next Steps for Deepening Your Knowledge:
- Monitor the Juno Mission's data: Visit the mission's official site to view the latest infrared maps which show the heat signature of the storm's roots.
- Compare historical sketches: Look up the "Hooke" and "Cassini" drawings from the 17th century to see how much the storm's appearance has shifted over 350 years.
- Explore the "Red Junior" phenomenon: Research how Oval BA formed to understand the life cycle of Jupiter's smaller, high-pressure vortices.