Nobody can pin a date on when Jupiter’s Great Red Spot will vanish, and anyone who claims otherwise is guessing. The storm has been shrinking steadily for well over a century, narrowing from a width that could have swallowed three Earths side by side to one that barely fits a single Earth today. That trend has led to periodic headlines predicting the Spot’s imminent death, sometimes within a decade or two. But recent spacecraft data from NASA’s Juno mission and the James Webb Space Telescope reveal a storm that is deeper, more energetic, and more structurally complex than the shrinking outline visible through a backyard telescope would suggest.
A Century and a Half of Shrinking
The Great Red Spot has been continuously observed since at least the 1830s, and a feature in approximately the same location was sketched by astronomers as far back as the late 1600s, though whether that was the same storm remains debated. What is not debated is the direction of change. In the late 1800s, the Spot stretched roughly 40,000 kilometers across its long axis. By the Voyager flybys in 1979, it had narrowed to about 23,000 kilometers. Today it spans roughly 16,000 kilometers, and its shape has shifted from a pronounced oval toward something closer to a circle. The rate of shrinkage has not been constant; it has accelerated somewhat in recent decades, which is part of what fuels worry that the storm could be on its last legs.
But size is only one variable, and not necessarily the most important one. A storm that is smaller is not automatically a storm that is weaker or dying. To understand whether the Great Red Spot is actually winding down, you have to look at what is happening inside it.
The Winds Are Actually Speeding Up
One of the more surprising findings of the past few years came from a Hubble Space Telescope study tracking the high-speed ring of winds that defines the Spot’s outer boundary. Over a full Jovian year of observations (roughly twelve Earth years), researchers found that the mean wind speeds in that ring increased by about four to eight percent between 2009 and 2020, even as the Spot continued to get smaller.1Geophysical Research Letters. Evolution of the Horizontal Winds in Jupiter’s Great Red Spot From One Jovian Year of HST/WFC3 Maps That finding undercuts the simple narrative that the storm is fading away. If a vortex were truly dissipating, you would expect its winds to slow. Instead, the storm appears to be tightening, concentrating its energy into a smaller footprint.
Think of an ice skater pulling their arms in during a spin. The skater’s body gets smaller, but the spin speeds up because angular momentum is being conserved. Something loosely analogous may be happening with the Great Red Spot. A shrinking circumference does not mean less total rotational energy; it can mean the same energy packed more densely. Whether that process can continue indefinitely or whether the storm will eventually hit some physical limit is one of the open questions in planetary science.
How Deep the Storm Reaches
For centuries, astronomers could only see the cloud tops of the Great Red Spot. Juno changed that. Using gravity measurements from twelve encounters with Jupiter, including two direct overflights of the Spot, researchers determined that the storm’s density structure extends down to roughly 500 kilometers below the visible cloud level.2PubMed. The depth of Jupiter’s Great Red Spot constrained by Juno gravity overflights A separate analysis using Juno’s microwave radiometer confirmed the vortex extends at least a couple of hundred kilometers deep.3The Astrophysical Journal Letters. Determining the Depth of Jupiter’s Great Red Spot with Juno: A Slepian Approach
That matters because it tells us the Great Red Spot is not a superficial weather pattern skimming the top of the atmosphere. The microwave radiometer data showed that the vortex roots extend deeper than the altitude where water is expected to condense, and density inversion layers were identified within the structure.4PubMed. Microwave observations reveal the deep extent and structure of Jupiter’s atmospheric vortices In other words, the storm has deep plumbing that connects it to layers of the atmosphere well below anything visible from the outside. A storm anchored hundreds of kilometers deep is not something that fizzles out because its cloud-top outline shrinks a few thousand kilometers.
What Keeps the Storm Fed
On Earth, hurricanes draw their energy from warm ocean water and lose it quickly once that fuel source is cut off, which is why they weaken over land or cold currents. Jupiter has no ocean surface at all. The Great Red Spot sits in a hydrogen-helium atmosphere that extends thousands of kilometers deep, and the planet itself radiates substantially more energy than it receives from the Sun. That internal heat, thought to come from the slow gravitational contraction of the planet’s interior, drives convection and weather systems across Jupiter’s atmosphere.
The role of moist convection, specifically the latent heat released when water vapor condenses at depth, also appears significant. A dramatic example came during the 2010–2011 revival of Jupiter’s South Equatorial Belt, when convective eruptions triggered over roughly a hundred days were powered by the energy released as water condensed. The plumes rose from the water cloud base and diverged in the upper troposphere, creating massive disturbances visible from Earth.5Icarus. Moist convection and the 2010–2011 revival of Jupiter’s South Equatorial Belt The Great Red Spot likely taps into similar convective processes, meaning it has access to a fuel supply that is not going away any time soon.
Three-dimensional simulations of turbulent convection in rotating spherical shells offer another piece of the puzzle. These models show that rotating turbulent convection naturally generates deep, axially aligned cyclones and anticyclones, and that Jupiter’s deep magnetic dynamo may actually promote the formation of additional large anticyclones in overlying atmospheric layers.6PubMed Central. Deep convection-driven vortex formation on Jupiter and Saturn The Great Red Spot is an anticyclone, a high-pressure system spinning counter to the surrounding flow. If Jupiter’s internal dynamics actively favor the creation and maintenance of such vortices, the Spot is not just a relic clinging to life. It is a feature the planet’s physics wants to produce.
Connections to the Upper Atmosphere
The influence of the Great Red Spot extends far above its visible cloud tops, not just below them. Observations have identified a temperature hotspot in Jupiter’s upper atmosphere directly above the storm, hundreds of kilometers higher than the weather layer. That hotspot cannot be explained by solar heating or any mechanism acting from above. By process of elimination, researchers concluded it must be heated from below, providing strong evidence that acoustic or gravity waves propagate upward from the storm into the upper atmosphere.7PubMed. Heating of Jupiter’s upper atmosphere above the Great Red Spot
This is relevant to the disappearance question because it shows the Great Red Spot is not an isolated bubble of swirling cloud. It is dynamically coupled to regions of Jupiter’s atmosphere both above and below it. That kind of coupling makes it harder for the storm to quietly wind down. Its energy budget is entangled with large-scale atmospheric processes, which means the Spot’s fate probably depends less on its own internal dynamics and more on broad shifts in Jupiter’s global circulation patterns.
What JWST Is Revealing
The James Webb Space Telescope has added a new layer of detail that earlier instruments could not provide. In July and August 2022, JWST’s Mid-Infrared Instrument mapped the Great Red Spot across wavelengths from about 5 to 28 micrometers, coordinated with simultaneous observations from Hubble, ground-based telescopes, and amateur astronomers to build a comprehensive picture of the storm’s thermal structure and chemical composition.8Journal of Geophysical Research: Planets. The Thermal Structure and Composition of Jupiter’s Great Red Spot From JWST/MIRI
Mid-infrared data are especially valuable because they reveal temperature gradients and chemical abundances at different altitudes, information that cloud-top imagery alone cannot provide. These observations help scientists distinguish between a storm whose deep structure is genuinely weakening and one whose visible outline is changing for other reasons, such as shifts in the altitude or opacity of the cloud layer that makes the Spot visible in the first place. If the storm’s thermal signature remains robust even as its visible footprint contracts, that would support the idea that the shrinkage is more cosmetic than structural.
JWST’s capabilities also allow long-term monitoring that was previously impossible at these wavelengths with this resolution. Repeated observations over the coming years should help settle whether the Spot’s internal temperature and chemical profile are trending in a direction consistent with decay, or whether they remain stable even as the cloud outline evolves.
Lessons from Neptune’s Vanishing Storms
To appreciate what makes Jupiter’s storm unusual, it helps to look at what happens on other giant planets. Neptune has its own large vortices, and they behave very differently. When Voyager 2 flew past Neptune in 1989, it photographed a massive storm dubbed the Great Dark Spot. By the time the Hubble Space Telescope looked at Neptune a few years later, that storm had disappeared entirely. Neptune then produced a new large dark spot, and that one vanished too.
In 2018, Hubble discovered yet another new Great Dark Spot in Neptune’s northern hemisphere, spanning roughly 11,000 by 5,000 kilometers at about 23 degrees north latitude, similar in size and drift rate to the original Voyager-era spot near 22 degrees south.9Geophysical Research Letters. Formation of a New Great Dark Spot on Neptune in 2018 Neptune’s pattern, then, is one of storm formation, dissipation, and reformation on timescales of just a few years. These storms appear, grow, and die with relative ease.
Jupiter’s Great Red Spot has done nothing of the sort. It has persisted for at least 190 years and possibly much longer, making it an extreme outlier among known planetary storms. The difference likely comes down to Jupiter’s greater mass, stronger internal heat output, and the specific dynamics of its banded zonal winds, which create stable “tracks” that a large vortex can ride for centuries. Neptune’s thinner atmosphere and different wind structure apparently cannot sustain large vortices for long. The comparison suggests that the Great Red Spot exists not by accident but because Jupiter’s atmosphere is structurally suited to maintaining it.
Why the Predictions Keep Being Wrong
Predictions of the Great Red Spot’s demise have surfaced periodically for decades. In 2019, dramatic images showed the Spot apparently shedding red material in what some observers described as “flaking,” prompting a wave of news coverage suggesting the storm was falling apart. Professional analysis told a calmer story: the Spot was interacting with smaller anticyclonic vortices that were being swept into its periphery, a process that has been documented many times before and does not indicate structural failure.
The core problem with forecasting is that no one has a predictive model of the Great Red Spot that reliably reproduces its behavior over long timescales. Simulations can generate vortices that resemble the Spot, and they can identify the mechanisms that sustain it, but they cannot yet tell you with confidence what the storm will look like in fifty years. The atmosphere is too complex, the interactions too nonlinear, and the observational record too short relative to the storm’s lifetime.
Some researchers have extrapolated the shrinkage trend linearly and arrived at dates in the 2030s or 2040s when the Spot’s visible outline would reach zero. But linear extrapolation of a nonlinear system is unreliable. It is the equivalent of noting that a child grew four inches last year and predicting they will be twelve feet tall by age thirty. The shrinkage rate could slow, plateau, or even reverse. And as the wind-speed data show, a smaller visible outline does not necessarily mean a weaker storm.
Could the Spot Survive but Change Beyond Recognition
There is a version of the story where the Great Red Spot “disappears” without actually dying. Its red color has varied over the centuries, sometimes darkening to a deep brick red and sometimes fading to a pale salmon or even blending into the surrounding clouds so thoroughly that it becomes hard to see visually. If the Spot shrank to a size where it was no longer the dramatic landmark amateur astronomers have come to expect, and if its color faded to something closer to the background clouds, it could effectively vanish from casual observation while still existing as a coherent atmospheric vortex.
The color itself is not well understood. The reddish hue is thought to come from complex organic molecules or sulfur-containing compounds produced by photochemical reactions in the upper cloud layers, but the exact chromophore has not been definitively identified. Changes in color could reflect shifts in the altitude of the cloud deck, variations in chemical composition, or changes in the amount of ultraviolet radiation reaching the relevant atmospheric layer. None of these necessarily have anything to do with the storm’s structural health. A Great Red Spot that turned white and shrank to the size of a typical Jovian oval would still be a major atmospheric vortex by any physical measure, even if it lost its status as the most photogenic feature in the solar system.
It is also worth considering that Jupiter has produced other long-lived ovals over the observed record. Oval BA, sometimes called “Red Spot Junior,” formed in the early 2000s from the merger of three smaller white ovals that had themselves persisted for about sixty years. Oval BA turned reddish for a time, then faded. The atmosphere clearly has the capacity to create and sustain large vortices over decades, and the Great Red Spot may be better understood as the largest and most persistent member of a population of such features rather than a unique, irreplaceable phenomenon.
What Amateur Observers Actually See
If you own a telescope and want to watch the Great Red Spot yourself, the practical reality is that the feature is still plainly visible in instruments as small as six inches of aperture under good seeing conditions. Its contrast against the surrounding South Tropical Zone varies from year to year and even month to month. During periods when the South Equatorial Belt fades (a phenomenon that has happened multiple times in the past century), the Spot can actually appear more prominent because its dark surroundings have brightened. During active periods, the Belt’s turbulence can make the Spot harder to pick out.
Amateur observers around the world contribute a surprising amount of useful data to professional researchers. Many of the 2019 “flaking” events were first documented by amateurs with backyard telescopes and planetary cameras. The JWST observations in 2022 were deliberately coordinated with amateur and ground-based professional monitoring to provide temporal context that a single space telescope snapshot cannot.8Journal of Geophysical Research: Planets. The Thermal Structure and Composition of Jupiter’s Great Red Spot From JWST/MIRI If the Spot does undergo dramatic changes in the coming years, the global network of amateur Jupiter observers will almost certainly catch it first, given that professional telescope time is limited and the Spot’s longitude rotates into view roughly once every ten hours.
For anyone worried they might miss their chance to see the Great Red Spot through a telescope, the honest assessment is that there is no reason to panic. The storm remains a substantial feature, its winds are stronger than they were a decade ago, and its deep structure extends hundreds of kilometers below the visible surface. Whether it will look the same in 2060 is genuinely uncertain, but its continued existence in some recognizable form over the next couple of decades seems far more likely than the dramatic collapse headlines have sometimes suggested.