If you were to look through a telescope at Jupiter tonight, you'd see a world that looks like a marble made of latte foam. But that one famous blemish, the Giant Red Spot, is basically the solar system’s most stubborn resident. It's been there since at least the 1830s. Maybe even since the 1600s, though scientists like Agustín Sánchez-Lavega have recently argued the "Permanent Spot" seen by Giovanni Cassini back then might actually be a completely different storm that died out before this one started.
People always say it’s big enough to swallow three Earths.
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Honestly? That’s old news. It’s shrinking. Fast.
Today, the Giant Red Spot is barely wider than a single Earth. It’s roughly 10,000 miles across now. Compare that to the 19th-century measurements of 25,000 miles, and you realize we’re watching a legend slowly deflate. But while it's getting skinnier, it's also getting taller. Think of it like a piece of clay on a potter's wheel. As you squeeze the sides, the top stretches upward. NASA’s Juno mission recently proved this thing has "roots" that go about 200 to 300 miles deep.
Why the Giant Red Spot hasn't died yet
On Earth, a hurricane hits the coast of Florida and peters out because it loses its heat source and hits solid ground. Jupiter has no ground. It’s just gas and liquid all the way down until things get weirdly metallic at the core. Because there’s no friction from a landmass, the Giant Red Spot just keeps spinning.
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It’s an anticyclone. High pressure.
It sits between two massive jet streams that move in opposite directions. This basically acts like a pair of conveyor belts, keeping the storm spinning in a permanent tug-of-war. But in the last couple of years, things have gotten weird. In 2024 and 2025, the Hubble Space Telescope caught the spot "jiggling." Dr. Amy Simon from NASA Goddard described it as behaving like a bowl of gelatin. It squeezes in and out every 90 days. We still don't really know why.
The mystery of the red color
You’d think we’d know what makes it red by now. We don't.
Basically, the upper clouds of Jupiter are mostly ammonia, but that stuff is white. The leading theory is that the storm’s ferocious winds—which can top 400 miles per hour at the edges—are dredging up chemicals from deep inside the planet. Specifically, ammonium hydrosulfide. When these chemicals hit the harsh UV radiation from the Sun, they go through a chemical tan. They turn that iconic brick-red or burnt orange color.
- Wind speeds: Over 400 mph at the perimeter.
- Rotation: It completes a full lap every six Earth days (counter-clockwise).
- Depth: About 300 miles—roughly 50 to 100 times deeper than Earth's oceans.
- Current state: Shrinking in width but growing in height.
Sometimes it’s not even that red. Some years it looks more like a pale salmon or a dirty beige. Stargazers in 2026 are finding it a bit easier to spot though, because Jupiter is at opposition this January. It's the brightest it will be all year.
Is it actually disappearing?
There was a lot of talk a few years ago about "flaking." Amateur astronomers saw red clouds peeling off the main storm like skin from a sunburn. People panicked. They thought the Giant Red Spot was finally breaking apart.
But it turns out the storm was just "eating" smaller vortices. This is called vortex cannibalism. The spot stays alive by swallowing smaller storms that get too close. It’s a predator.
While it is shrinking, it might not disappear. Some models suggest it will eventually reach a "stable" size where the internal pressure matches the surrounding jet streams. It might just become the "Average Red Spot."
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What to do if you want to see it
If you have a backyard telescope, now is the time. Since Jupiter is reaching opposition in January 2026, it’s closer to Earth than it’s been in a long time—about 394 million miles.
- Find the constellation Gemini. Jupiter is the brightest "star" there. It won't twinkle.
- You’ll need a telescope with at least 150x magnification to see the spot clearly.
- Check a transit app. Because Jupiter rotates every 10 hours, the spot is only visible half the time. If you don't see it, wait five hours and try again.
- Look for the Southern Equatorial Belt. The spot sits right on the edge of it.
Don't expect a neon red dot. It usually looks like a subtle indentation in the cloud belts, sorta like a thumbprint in clay.
The best way to stay updated is to follow the Juno mission's raw image gallery. NASA posts the unprocessed data there, and citizen scientists often turn them into the most beautiful photos you've ever seen. If you want to dive deeper into the physics, check out the latest papers in The Planetary Science Journal regarding the 90-day oscillation cycle—it’s the "hot" topic in Jovian weather right now.
Keep an eye on the Southern Equatorial Belt too. It sometimes disappears entirely, making the Giant Red Spot stand out even more against the white clouds. It's a reminder that nothing on Jupiter is actually permanent.