On Oct. 19, NASA reported on its website that the James Webb Space Telescope had discovered an equatorial jet stream on Jupiter, moving at 320 mph. It spans about 3,000 miles, and sits about 25 miles above the cloud layer in the lower stratosphere. The research, published on Oct. 19 in Nature Astronomy, points out that the jet stream is traveling 70 meters per second “faster than the zonal winds at the cloud level.”
Although high-level winds in Jupiter’s atmosphere have been known since the time of the Cassini mission (1997 to 2017)—a mission which snapped fabulous close-up images of Jupiter in a flyby as it made its way to its ultimate goal, Saturn—what is different this time is that with the combination of the Webb and Hubble telescopes’ images, scientists can create a 3-D image of the Jovian atmosphere, allowing them to investigate it more deeply than before. Insights they gain can be applied to Earth’s weather patterns, even though the two planets are extremely different. Several remarkable videos composed of still images by Cassini were published by NASA in June 2012.
Unlike the jet streams on Earth (two each in the North and South Hemispheres), which can snake around the Earth in undulating patterns, causing dramatic shifts in weather patterns, Jupiter’s jet stream travels in a straight band around the Equator; it also has been observed to have waves that move up and down along the length of the jet stream. Other anomalies called “chevrons"—V-shaped cloud formations on the edges of the jet stream—are as yet unexplained. Scientists are still puzzled by the ability of storms, such as the Great Red Spot, to persist in a stable pattern for hundreds of years, and for distinct bands of prevailing winds to exist and move in opposite directions from each other, and some in the opposite direction to Jupiter’s rotation.
“Jupiter has a complicated but repeatable pattern of winds and temperatures in its equatorial stratosphere, high above the winds in the clouds and hazes measured at these wavelengths,” explained team member Leigh Fletcher of the U.K.’s University of Leicester. “If the strength of this new jet is connected to this oscillating stratospheric pattern, we might expect the jet to vary considerably over the next 2 to 4 years—it’ll be really exciting to test this theory in the years to come…. It’s amazing to me that, after years of tracking Jupiter’s clouds and winds from numerous observatories, we still have more to learn about Jupiter, and features like this jet can remain hidden from view until these new NIRCam images were taken in 2022,” continued Fletcher.
