While this may seem like a Roadrunner and Sly Wolf cartoon (imagine that episode with giant magnets and “tornado seeds”), this is actually real science, and it's happening on Jupiter. ——Anthony
Magnetic tornadoes are stirring up haze at Jupiter's poles
Unusual magnetically driven eddies could produce Earth-sized concentrations of hydrocarbon haze
from UC Berkeley
While Jupiter's Great Red Spot has been a persistent feature of the planet for centuries, astronomers at the University of California, Berkeley, have discovered equally large spots at Jupiter's north and south poles that appear and disappear seemingly at random.
Visible only in ultraviolet wavelengths, these Earth-sized ovals are embedded in the layer of stratospheric haze that covers Earth's poles. When seen, the dark oval is almost always directly below each pole's bright auroral band, similar to Earth's northern and southern lights. These spots absorb more ultraviolet light than the surrounding area, making them appear darker in images from NASA's Hubble Space Telescope. In Hubble's annual images of the planet between 2015 and 2022, dark ovals appeared at the South Pole 75% of the time, while only one of eight images taken at the North Pole showed dark ovals.
The dark ultraviolet ovals hint at unusual processes occurring in Jupiter's strong magnetic field, which propagate down to the poles and deep into the atmosphere, much deeper than the magnetic processes that produce auroras on Earth.
Troy Tsubota and Michael Wong, University of California, Berkeley
Researchers at the University of California, Berkeley, and colleagues report this phenomenon today (November 26) in the journal natural astronomy.
Hubble first discovered dark ultraviolet ovals at the North and South Pole in the late 1990s, followed by the Cassini spacecraft that flew by Jupiter in 2000, but they attracted little attention. . However, when Troy Tsubota, an undergraduate student at the University of California, Berkeley, conducted a systematic study of recent Hubble images, he found that they were a common feature of the South Pole—he counted eight between 1994 and 2022. Southern Ultraviolet Dark Oval (SUDO). Dark ellipse (NUDO).
Most of Hubble's images were taken as part of the Outer Planet Atmosphere Legacy (OPAL) project, which was led by Amy Simon, a planetary scientist at NASA's Goddard Space Flight Center and co-author of the paper. (Amy Simon) Leadership. OPAL astronomers use Hubble to conduct annual observations of Jupiter, Saturn, Uranus and Neptune to understand their atmospheric dynamics and evolution over time.
“Within the first two months, we realized that these OPAL images were like a gold mine in a sense, and I was quickly able to set up this analysis pipeline and send all the images out to see what we got,” said Tsubota . “That's when we realized we could actually do some good science and real data analysis, and started talking with collaborators about why these phenomena were occurring.”
Huang and Pingtian consulted two experts on planetary atmospheres – Tom Stallard of Northumbria University in Newcastle upon Tyne, UK, and Zhang Xi of the University of California, Santa Cruz – to determine what causes these regions of thick fog. Stallard speculates that the dark ellipse is likely churned up from above by vortices created when Earth's magnetic field lines experience friction at two very distant locations: in the ionosphere, which Stallard and other astronomers have previously used using ground-based telescopes. Detecting rotational motion in the ionosphere, which Stallard and other astronomers previously detected using ground-based telescopes, on the volcanic moon Io, which releases a layer of hot, ionized plasma around the planet.
Vortices spin fastest in the ionosphere and gradually weaken as they reach deeper layers. Like a tornado settling on dusty ground, the deepest parts of the vortex churned up the hazy atmosphere, creating the dense spots observed by Huang and Pingtian. It's unclear whether this mixing will clear more fog from below or create additional fog.
Based on the observations, the team suspects that the ellipse forms over the course of about a month and dissipates within a few weeks.
“The haze in the black oval is 50 times thicker than typical concentrations,” Zhang said, “which suggests it may be formed due to spinning vortex dynamics rather than chemical reactions triggered by high-energy particles from the upper atmosphere. Our Observations show that the time and location of these high-energy particles are independent of the appearance of dark ellipses.
These findings are exactly what the OPAL project aims to discover: how the atmospheric dynamics of the solar system's giant planets differ from what we know on Earth.
“Studying the connections between different atmospheres is very important for all planets, whether exoplanets, Jupiter or Earth,” Huang said. “We see evidence of processes that connect everything throughout the Jupiter system, from the internal dynamo to the moons and their plasma torii, to the ionosphere to stratospheric haze. Finding these examples helps us understand the planet as a whole.”
This work was supported by NASA.
Journal – Nature Astronomy Papers: 10.1038/s41550-024-02419-0
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