A team of astronomers discovered a strange polygonal atmospheric structure on Saturn near the planet’s south pole. This 10-sided shape, known as a decagon, joins one of the gas giant’s most famous features: a hexagon near the north pole that was first observed 44 years ago. Images of the new decagon were captured by the Hubble Space Telescope, and the discovery was recently published in the journal Science Advances.The formations at both the north and south poles aren’t solid structures, like a wall or a rock formation. Saturn doesn’t even have a defined solid surface like Earth’s crust. If you were to descend through the atmosphere of the ringed planet, the pressure and density would progressively increase, but you would never reach a “ground” on which to land. Instead, what astronomers have witnessed are patterns formed by clouds, albeit very unusual ones.Each side of the decagon measures approximately 16,800 kilometers, which is a few thousand miles longer than the diameter of Earth. Near the feature is a jet stream reaching speeds of 116 meters per second, or nearly 260 miles per hour. By way of comparison, a Category 5 hurricane—the most intense storm level possible on Earth—is defined by winds above 157 miles per hour. Interestingly, although the jet stream circulates at tremendous speed, the decagon pattern shifts at a mere 2.5 meters per second—less than 6 miles per hour.Photograph of the new decagon at Saturn’s south pole