Titan, the largest moon of Saturn, is covered in oceans, seas, and lakes of hydrocarbons. Astronomers lately spotted something strange in one liquid reservoir - a giant white blob. This feature has never been seen before by researchers. It appeared in the northern sea of Titan, Ligeia Mare, in July 2013, before disappearing.

Some scientists started calling the feature a "magic island," after it seemed to miraculously appear in a single image from the Cassini orbiter.

That spacecraft was launched in 1997, on a mission to explore the ringed planet in the greatest detail ever examined. After reaching Saturn, the vehicle launched a lander - Huygens - to the surface of Titan.

Islands are not known to suddenly appear and disappear. Researchers have come up with an explanation for the magic island; they believe the orbiter either recorded a large wave, rushing across the hydrocarbon lake, or bubbles rising up from under the surface.

"The Cassini spacecraft, which arrived at Saturn in 2004 in the midst of northern winter and southern summer, has observed surface changes, including shoreline recession, at Titan's South Pole and equator. However, active surface processes have yet to be confirmed in the lakes and seas in Titan's North Polar Region," investigators wrote in an article announcing their study. 

Summer is currently on the way to the northern hemisphere of the giant satellite. Extra energy, provided by solar heating on that half of the planetary body, may be responsible for the observation, according to researchers. Large waves, created by rising temperatures, may have been seen by astronomers as a mysterious, if temporary, island. Another theory holds that solid material which sank in the hydrocarbons during winter may be rising in spring. If this substance were nearly the same density of the chemicals that make up liquid reservoirs on Titan, it could remain suspended, only being seen for short periods of time. 

"Likely, several different processes - such as wind, rain and tides - might affect the methane and ethane lakes on Titan," Jason Hofgartner, a graduate student of planetary sciences at Cornell University, said. 

Seas on Titan are roughly the size of the Great Lakes in the northern United States. 

Astronomers hope that by understanding the processes that drive weather on Titan, they may be better able to uncover the secrets of water here on Earth. 

Investigation of Titan's "magic island," and the theory of waves or bubbles as a mechanism for the event, was published in the journal Nature Geoscience.