NASA's Cassini probe has spotted a storm on Saturn that has "consumed" itself. The massive storm whirled around the planet until it ran into its own tail end and dispersed. A new paper on the event, published in the journal Icarus, describes it as the first time researchers have ever seen such a thing happen in the solar system.
"This Saturn storm behaved like a terrestrial hurricane - but with a twist unique to Saturn," said Andrew Ingersoll, co-author of the paper and a Cassini imaging team member. "Even the giant storms at Jupiter don't consume themselves like this, which goes to show that nature can play many awe-inspiring variations on a theme and surprise us again and again."
The storm was first detected in December of 2010, forming from warm gas in the planet's atmosphere. It began moving west along 33 degrees north latitude, spinning clockwise. The storm eventually stretched 190,000 miles (300,000 kilometers) around the planet. With no mountains or other land to impede it, the storm eventually ran into itself in June 2011 and faded away.
"This thunder-and-lightning storm on Saturn was a beast," said Kunio Sayanagi, lead author on the paper and a Cassini imaging team associate at Hampton University. "The storm maintained its intensity for an unusually long time. The storm head itself thrashed for 201 days, and its updraft erupted with an intensity that would have sucked out the entire volume of Earth's atmosphere in 150 days. And it also created the largest vortex ever observed in the troposphere of Saturn, expanding up to 7,500 miles (12,000 kilometers) across."
Though the storm was the longest-running of the massive storms that occur in Saturn's northern hemisphere every 30 (Earth) years, it isn't the longest storm ever detected on the gas giant. That honor goes to a storm 100 times smaller, which formed in the southern hemisphere's "storm alley" and lasted 334 days in 2009.
"Cassini's stay in the Saturn system has enabled us to marvel at the power of this storm," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory (JPL). "We had front-row seats to a wonderful adventure movie and got to watch the whole plot from start to finish. These kinds of data help scientists compare weather patterns around our solar system and learn what sustains and extinguishes them."