Jupiter’s Great Red Spot (GRS) has long been a mystery to astronomers.
This massive storm, larger than Earth, has swirled in Jupiter’s atmosphere for over 150 years, but scientists recently made an unexpected discovery.
Using NASA’s Hubble Space Telescope, researchers observed that the storm is wobbling and changing in size over time, almost as if it’s “jiggling like a bowl of gelatin.”
From December 2023 to March 2024, Hubble captured images of the GRS every day, allowing scientists to create a time-lapse movie showing the storm’s unusual behavior.
Normally thought of as steady and stable, the Great Red Spot was seen shifting shape and size, expanding and contracting in an unexpected oscillation cycle over 90 days.
“While we knew its location could vary, we didn’t expect to see its size change this way,” said Amy Simon from NASA’s Goddard Space Flight Center.
One reason for this strange movement could be the powerful jet streams to the north and south of the GRS, which act like barriers, trapping the storm in its place.
According to Mike Wong from the University of California, these jet streams may be squeezing the GRS, causing it to bulge out and shrink back in, like too much filling in a sandwich. This adds extra pressure to the storm, impacting its shape.
Hubble’s observations also revealed that the core of the GRS becomes brighter when it is at its largest.
This could mean that less haze in Jupiter’s upper atmosphere allows more sunlight to reflect off the storm.
The researchers believe that the GRS may continue shrinking, eventually stabilizing into a more compact form. For now, however, its changes remain a mystery, and the cause of the 90-day cycle is still unknown.
The findings have given scientists new insights into the giant storm, helping them understand not only Jupiter’s atmosphere but also how massive storms might behave on planets outside our solar system.
The team presented their results at the 56th annual meeting of the American Astronomical Society’s Division for Planetary Sciences.
Researchers hope that with future high-resolution images, they may uncover more details about the cause of this oscillation.
Until then, the Great Red Spot keeps astronomers on their toes, as it wobbles and shrinks on its journey across Jupiter’s skies.
