Hubble observations revealed a giant decagon swirling in Saturn’s icy ammonia clouds over the south pole, a newly identified jet-stream pattern scientists say is still evolving.
The Spanish-led team said the formation likely emerged between 2017 and 2023, when Saturn’s south pole was tilted away from Earth and earlier observations could not see it.
One side already stretches beyond 10,000 miles, and the decagon drifts east at about 6 mph, unlike Saturn’s long-known north-pole hexagon, which is largerly stationary and has persisted for more than 40 years.
The Science Advances study suggests Saturn’s polygonal storms may be less unique than once thought and could help explain weather dynamics on giant gas planets over the next several years of improved viewing.