The storm on Saturn as seen by the Cassini spacecraft. (AP)

London, Nov. 11: A colossal hurricane-like storm with a well-developed eye ringed by towering clouds has been observed churning at Saturn’s south pole, the first time such an event has been detected on a planet other than Earth.

The storm on the giant, ringed planet measures about 5,000 miles wide, roughly two- thirds the diameter of Earth, with winds howling clockwise at 350 mph. Jupiter’s Great Red Spot, which swirls counter-clockwise, is far bigger, but is less like a hurricane because it lacks the typical eye and eye wall.

The images were captured by the Cassini spacecraft as it passed about 210,000 miles from the planet as part of its exploration of Saturn and its moons.

The sequence taken by Cassini's camera over three hours reveals the shadow cast by a ring of towering clouds surrounding the pole, and two spiral arms of clouds extending from the central ring. These ring clouds, 20 to 45 miles above those in the storm's heart, are two to five times taller than the clouds of Earth’s thunderstorms and hurricanes.

Eye-wall clouds are a distinguishing feature of hurricanes on Earth. They form where moist air flows inward across the ocean's surface, rising vertically and releasing heavy rain around an interior circle of descending air that stares out of the eye of the storm.

Though it is uncertain whether such moist convection is driving Saturn's storm, the dark “eye” at the pole, the eye-wall clouds and the spiral arms indicate a hurricane-like system.

Michael Flasar, an astrophysicist involved in the mission at Nasa’s Goddard Space Flight Centre in Greenbelt, Maryland, said the storm looked just like water swirling down the plug hole of a bath tub, only on a gigantic scale. “We’ve never seen anything like this before,” Flasar said.

The giant storm differs from Earth hurricanes in part because it is stuck at the pole rather than drifting, as such storms do on this planet, and because it did not form over a liquid ocean, with Saturn being a gaseous planet.