Scientists are investigating a mystery object that appeared and then vanished again from a giant lake on Titan, the largest moon of Saturn.
They spotted the object in an image taken by Nasa's Cassini probe last year. Pictures of the same spot captured nothing before or some days later.
Astronomers have named the blob the "magic island" until they have a better idea what they are looking at. "We can't be sure what it is yet because we only have the one image, but it's not something you would normally see on Titan," said Jason Hofgartner, a planetary scientist at Cornell University in New York. "It is not something that has been there permanently."