(CNN) -- NASA says the Cassini spacecraft recorded the aftermath of a massive storm on Saturn that let out an "unprecedented belch of energy."
Not only was the size of the storm unusual, but what the storm was made of left scientists puzzled.
The source of the cosmic burp, which rapidly changed the atmosphere's temperature, was ethylene gas, an odorless, colorless gas that has rarely been observed on Saturn, NASA said.
"This temperature spike is so extreme it's almost unbelievable," said Brigette Hesman, the study's lead author who works at Goddard. "To get a temperature change of the same scale on Earth, you'd be going from the depths of winter in Fairbanks, Alaska, to the height of summer in the Mojave Desert," Hesman said in a statement released by NASA.
Scientists still haven't figured out from where the ethylene gas came.
By comparison, a storm of similar size on Earth would cover North America from top to bottom and wrap the planet many times, researchers said.
The Cassini spacecraft first detected the disruption on December 5, 2010, and has been following it since, but researchers said the ethylene gas disruption that followed the storm was unexpected.
A storm this size happens once every 30 years, or once every Saturn year, NASA scientists said.
Launched in 1997, the Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.
A full report will be published in November's issue of the Astrophysical Journal.