New spots discovered on Jupiter's poles can fit Earth inside them

Observations between 2015 and 2022 show that these features are more prevalent at the south pole, appearing in 75% of the images, while they are rarely seen at the North Pole.

In Short

• It hints at unique processes occurring within Jupiter's powerful magnetic field
• These processes appear to extend from the poles deep into the atmosphere
• The discovery stems from a systematic study of Hubble images

Astronomers at the University of California, Berkeley have made a new discovery on Jupiter, revealing the presence of Earth-sized dark ovals at the planet's poles just as the Great Red Spot.

These enigmatic features, visible only in ultraviolet light, appear and disappear seemingly at random, adding a new layer of complexity to our understanding of the gas giant.

The dark ovals, embedded in stratospheric haze layers capping Jupiter's poles, are typically found just below the planet's auroral zones. They absorb more UV light than their surroundings, making them appear dark in images captured by NASA's Hubble Space Telescope.

Observations between 2015 and 2022 show that these features are more prevalent at the south pole, appearing in 75% of the images, while they are rarely seen at the north pole.

This phenomenon, reported in Nature Astronomy, hints at unique processes occurring within Jupiter's powerful magnetic field. These processes appear to extend from the poles deep into the atmosphere, surpassing the depth of magnetic interactions that produce Earth's auroras.

The discovery stems from a systematic study of Hubble images conducted by UC Berkeley undergraduate Troy Tsubota. His analysis revealed eight southern UV-dark ovals (SUDO) between 1994 and 2022, while only two northern UV-dark ovals (NUDO) were identified in 25 global maps of Jupiter's north pole.

Experts theorise that these dark ovals may be formed by a vortex created by friction between the planet's magnetic field lines in the ionosphere and the plasma sheet around Jupiter, supplied by its volcanic moon Io.

This vortex could be stirring up the hazy atmosphere, creating dense spots visible in UV light.

The ovals are believed to form over about a month and dissipate within a couple of weeks. The haze in these dark areas is estimated to be 50 times thicker than typical concentrations, suggesting a dynamic formation process rather than chemical reactions triggered by high-energy particles.

This discovery, part of the Outer Planet Atmospheres Legacy (OPAL) project, provides valuable insights into the atmospheric dynamics of gas giants, contributing to our broader understanding of planetary atmospheres across the solar system and beyond