Probe Observes Storms Merging on Saturn

Three months before its arrival at Saturn, the Cassini spacecraft has observed two storms in the act of merging into one larger storm. This is only the second time this phenomenon has been observed on the ringed planet. With diameters close to 621 miles, both storms were seen moving west, relative to the rotation of Saturn’s interior, for about a month before they merged on March 19-20.

On Earth, storms last for a week or so and usually fade away when they enter the mature phase and can no longer extract energy from their surroundings. On Saturn and the other giant planets, storms last for months, years, or even centuries, and instead of simply fading away, many storms on the giant planets end their lives by merging. How they form, however, is still unclear.