The dark UV ovals were first detected by NASA’s Hubble Space Telescope during the late 1990s at the north and south poles. During the Cassini spacecraft’s flyby of Jupiter in 2000, it also confirmed these ovals at Jupiter’s north pole, but the ovals did not get a lot of attention from scientists.

Dark ovals in Jupiter's polar haze, visible only at UV wavelengths, were first noticed 25 years ago, then ignored. A UC Berkeley study shows that these dark UV ovals are common, appearing at the south pole in 75% of Hubble Space Telescope images taken since 2015.

UC Berkeley researchers have discovered that dark ovals at Jupiter’s poles, whose presence was previously unexplained, are caused by “magnetic tornadoes.”

The dark UV ovals were first spotted by NASA’s Hubble spacecraft in the late 1990s, but have only recently been studied in depth.

Astronomers have discovered mysterious, Earth-sized dark spots at Jupiter’s poles that appear and disappear unpredictably. These spots, only visible in ultraviolet (UV) light, are embedded in a thick haze at the poles and seem to be linked to the planet’s strong magnetic field.

New research reveals that Jupiter’s magnetic tornadoes generate massive Earth-sized storms, visible only in ultraviolet light.

The Great Red Spot is not the only Earth-sized atmospheric disturbance seen on Jupiter. That dramatic storm remains number one for size and power in the Solar System, but ultraviolet (UV) observations from Hubble have now revealed that Earth-size ovals of haze are being stirred up over Jupiter's polar regions.