Juno spots 3,000 km decagon wave on Saturn

Scientists have spotted a strange wave in Saturn’s atmosphere that looks like a ten‑sided polygon, or decagon, and it appears to have formed only recently. The discovery came from data collected by the Juno spacecraft’s infrared imaging system, which has been mapping the planet’s weather patterns since 2016.

The finding is important because waves in a planet’s atmosphere reveal how heat and momentum are transported. On Earth, such waves help drive weather and climate. On Saturn, where temperatures drop to –180 °C and winds can reach 400 km/h, the decagon may signal a new type of atmospheric instability. Researchers are puzzled because the pattern does not match any of the known wave types that Juno has observed before.

Juno’s instruments measured the decagon’s size, which spans about 3,000 km across a single band of clouds. The wave is faint, but its shape is clear in the infrared images. Scientists are comparing the data with computer models of Saturn’s atmosphere, hoping to see whether the decagon is a short‑lived feature or the first of a new class of waves. The team has already shared preliminary findings with the planetary science community, and several experts have suggested that it could be linked to a sudden change in the planet’s internal heat flow.

The next step is to watch the wave over the coming months. Juno will continue to take images of the same region, allowing scientists to track the decagon’s evolution. If the wave persists or grows, it could help refine models of Saturn’s deep atmosphere and the way its magnetic field interacts with the surrounding gas. The discovery also offers a new target for future missions, such as the planned Saturn Orbiter and Probe, which could carry instruments specifically designed to study atmospheric waves.