Dark Ovals As Big As Earth Keep Appearing On Jupiter, Scientists Say

Jupiter, renowned for its iconic Great Red Spot, holds another atmospheric mystery: massive Earth-sized dark ovals of at its poles. Appearing and disappearing apparently at randomm, and visible only in ultraviolet light, the dark ovals may be the result of tornado-like phenomena.

New NASA-supported research published this week in Nature Astronomy reveals that these dark ovals, which appear sporadically at Jupiter’s poles, are akin to tornadoes and create dense patches of haze far below the planet’s northern and southern lights.

Magnetic Mysteries

Jupiter’s south polar regions frequently features the dark ovals, but not all the time, forming in about a month and dissipating within weeks. Only 75% of annual observations of the giant planet by NASA’s Hubble Space Telescope between 1994 and 2022 reveal them. The dark ovals are much rarer close to in Jupiter’s north pole, where they appear in just a couple of the 25 annual images. The ovals are dark in ultraviolet light because they absorb more light than the surrounding atmosphere.

Dark Ovals

This is not the first time dark ovals have been found on Jupiter. Discovered by Hubble in the late 1990s and by NASA’s Cassini spacecraft in 2000, they have nevertheless been largely ignored until now. “In the first two months, we realized these OPAL images were like a gold mine,” said Troy Tsubota, an undergraduate ay UC Berkeley, who is triple 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 contains rapidly spinning vortices.. They’re caused by its powerful magnetic field lines interacting with both charged particles high above the atmosphere and with a plasma originating from Io, one of Jupiter’s moons and the most volcanically active place in the solar system. The vortices extend from its upper atmosphere and weaken as they extend deeper, but the turbulence they cause stirs the stratosphere to produce patches of dense haze.

Internal Dynamo

“Studying connections between different atmospheric layers is very important for all planets, whether it’s an exoplanet, Jupiter or Earth,” said co-author 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.”

It’s thought that knowing more about how Jupiter’s complex magnetic fields and atmospheric dynamics work will give planetary scientists insights into understanding both Earth’s weather systems and those on planets orbiting other stars.