Jupiter, famous for its iconic Great Red Spot, harbors another atmospheric enigma: enormous, Earth-sized dark ovals at its poles. These mysterious features appear and vanish seemingly at random, visible only in ultraviolet light. Scientists believe the ovals may result from tornado-like activity.
New NASA-funded research, recently published in Nature Astronomy, sheds light on these dark ovals. The study suggests they resemble tornadoes and generate dense haze patches deep beneath Jupiter’s northern and southern auroras.
Magnetic Mysteries
Dark ovals frequently appear in Jupiter’s south polar region but only sporadically, forming within a month and dissipating in weeks. NASA’s Hubble Space Telescope recorded these features in about 75% of its annual observations of Jupiter between 1994 and 2022. In contrast, the northern polar region exhibits them in only a handful of the 25 annual images. These ovals absorb ultraviolet light more effectively than their surroundings, making them stand out as dark spots.
Dark Ovals
This isn’t the first time scientists have identified dark ovals on Jupiter. Hubble first spotted them in the late 1990s, followed by NASA’s Cassini spacecraft in 2000. However, they remained largely overlooked until now. “In the first two months, we realized these OPAL images were like a gold mine,” said Troy Tsubota, an undergraduate at UC Berkeley majoring in physics, mathematics, and computer science. “That’s when we realized we could actually do some good science … about why these show up.”
Spinning Vortices
Jupiter’s atmosphere is filled with rapidly spinning vortices caused by its powerful magnetic field lines. These lines interact with charged particles above the atmosphere and plasma from Io, Jupiter’s volcanically active moon. The vortices stretch from the upper atmosphere, weakening as they penetrate deeper, but their turbulence stirs the stratosphere, forming dense haze patches.
Internal Dynamo
“Studying connections between different atmospheric layers is very important for all planets, whether it’s an exoplanet, Jupiter, or Earth,” said Michael Wong, a planetary scientist at UC Berkeley’s Space Sciences Laboratory. “We see evidence for a process connecting everything in the entire Jupiter system.”
Understanding Jupiter’s intricate magnetic fields and atmospheric dynamics may provide scientists with valuable insights into weather systems on Earth and exoplanets.
