NASA’s Hubble Observes Jupiter’s Red Spot Behaving Like a Stress Ball

Astronomers have observed Jupiter’s famous Great Red Spot (GRS), an anticyclone large enough to engulf Earth, for at least 150 years. But there are always new surprises – especially when the Hubble Space Telescope’s NASA is taking a closer look.

New Hubble observations of the famous red storm, collected over 90 days between December 2023 and March 2024, reveal that the GRS is not as stable as it might seem. The latest data shows the GRS shaking like a bowl of gelatin. The combined Hubble images allowed astronomers to compile a long-term movie of the GRS’s erratic behavior.

“Although we knew that its oscillations varied slightly along its length, we did not expect to see the magnitude of the oscillate again. As far as we know, it has not been known before,” said Amy Simon of NASA Goddard Space Flight Center in Greenbelt. Maryland, lead author of a scientific paper published in The Planetary Science Journal. “This is really the first time we’ve had a proper image of the GRS. With Hubble’s high resolution we can say that the GRS is in and out at the same time as it moves through fast and slow. That was very unexpected, and there are currently no hydrodynamic explanations.”

Hubble monitors Jupiter and other exoplanets every year through the Outer Planet Atmospheres Legacy (OPAL) program led by Simon, but these observations came from a program dedicated to GRS. Understanding the patterns of the largest storms in the solar system puts the concept of hurricanes on Earth in a broader universe, which can be used to better understand the weather on planets around other stars.

Simon’s team used Hubble to zoom in on the GRS for a closer look at its size, shape and subtle color changes. “When we look closely, we see a lot of things are changing every day,” said Simon. This includes observations of ultraviolet light that show that the isolated core of the storm is brightest when the GRS is at its largest during its oscillation cycle. This indicates less haze absorption in the upper region.

“As it accelerates and decelerates, the GRS pushes jet streams of air north and south of it,” said co-researcher Mike Wong of the University of California, Berkeley. “It’s like a sandwich where the slices of bread are forced out when there’s too much filling in the middle.” Wong compared this to Neptune, where dark spots can drift freely in latitude without strong jet streams to catch them. Jupiter’s Great Red Spot has been held in the southern part of the latitude, trapped between the jet streams, for the measurement of the observations of the telescopes of the Earth.

The group has continued to watch the GRS decline since the OPAL program began 10 years ago. They predict that it will continue to shrink before taking on a stable, low-elevation shape. “Now it’s filling its latitude sheet more than the airspace. Once it shrinks into that band the winds will really take hold,” said Simon. The team predicts that the GRS may be stable in size, but so far Hubble has only observed one oscillation cycle.

The researchers hope that in the future more high-resolution images from Hubble may identify other Jovian features that show the main cause of the oscillation.

The results are presented at the 56th annual meeting of the American Astronomical Society Division for Planetary Sciences, Boise, Idaho.

The Hubble Space Telescope has been in operation for more than three decades and continues to make important discoveries that affect our fundamental understanding of the universe. Hubble is an international collaboration project between NASA and ESA (European Space Agency). NASA’s Goddard Space Center in Greenbelt, Maryland, manages the telescope and mission. Lockheed Martin Space, based in Denver, Colorado, also supports missions at Goddard. The Space Telescope Science Center in Baltimore, Maryland, managed by the Association of Universities for Research in Astronomy, manages Hubble’s scientific activities for NASA.