Jupiter's Great Red Spot wobbles like Jell-o, according to Hubble snaps

After observing Jupiter's Great Red Spot (GRS) with the Hubble Space Telescope for 90 days, scientists have determined that it behaves like a "bowl of gelatin."

That finding, which challenges conventional wisdom that the extraterrestrial anticyclone is relatively stable, appeared in a paper published on Wednesday and summarized by NASA on the same day.

Ninety days is considered a single oscillation cycle for the GRS. Eight dates were chosen during the cycle in which scientists measured various of the storm's characteristics, including longitudinal position, size and shape.

"While we knew its motion varies slightly in its longitude, we didn't expect to see the size oscillate. As far as we know, it's not been identified before," explained Amy Simon, who leads NASA's Outer Planet Atmospheres Legacy program (OPAL) and authored the study.

"This is really the first time we've had the proper imaging cadence of the GRS. With Hubble's high resolution we can say that the GRS is definitively squeezing in and out at the same time as it moves faster and slower. That was very unexpected, and at present there are no hydrodynamic explanations," she noted.

Here's the wobble in a vid.

Youtube Video

• Severe solar storm could disrupt power, communications
• Netflix on Mars? Yeah maybe, thanks to NASA's laser comms demo
• NASA switches off Voyager 2 plasma instrument to stretch out juice
• US govt hiding top hurricane forecast model sparks outrage after deadly Helene

Simon's co-author Mike Wong chose to refer to the GRS as a different food product. He compared the storm to a sandwich in which "the slices of bread are forced to bulge out when there's too much filling in the middle." In this comparison, the bread on the sandwich is windy jet streams that accelerate and decelerate, but ultimately hold the storm within a fixed zone.

That bulging will ultimately stop as the storm shrinks and takes on a less-elongated, more stable shape, predicted the scientist.

The debate over whether it resembles a bowl of Jell-o or a sandwich leads The Reg to wonder if perhaps the scientists are feeling a bit hungry.

Another finding discovered during the 90-day observation is that the core of the storm had an increase in UV brightness when the storm was at its largest – indicating less absorption of light by haze. That larger width occurred when the spot was it its slowest absolute drift – in other words, when it changed the least longitudinally.

"The GRS may interact with the surrounding flow more when accelerating and then relax toward equilibrium in between," the authors wrote.

The "high-velocity red collar" also changed in hue, but out of phase with oscillations.

The oscillations are common among other vortices – like those on Jupiter and Neptune – but the cause of the GRS's oscillations is unknown.

The researchers advocated for longer, more frequent studies of the spot, particularly as it continues to decrease in size. They suggested that now size changes are better understood, the vast database of amateur observation and GRS measurements can be mined to learn more about Jupiter's atmosphere and storms.

Extending the imaging wavelength coverage – particularly into long wavelengths – would also be useful, and could help determine if the wind changes speed below the GRS. Detailed circulation modelling could provide even deeper insights, noted the scientists.

According to NASA, understanding the mechanisms underpinning the solar system's largest storm puts the study of hurricanes on Earth "into a broader cosmic context." ®