Researchers have outlined their best explanation for a mysterious "magic island" that has been spotted on Saturn's moon Titan.

NASA's Cassini spacecraft captured the island during a flyby in 2013, but the island vanished by the time it passed next, according to a study published in the journal Nature Geoscience.

The island appeared as a bright splotch floating in the Ligeia Mare, which is one of the seas of ethane and methane found at Titan's north pole.

The island was seen in pictures from a Cassini flyby of Titan back on July 10, 2013. It is nowhere to be found in imagery of Ligeia Mare taken on three previous flybys however.

The feature had vanished by the time the next flyby took place, which was July 26, and was also not visible during two subsequent flybys.

"'Magic island' is a colloquial term that we use within the team to refer to this. But we don't actually think it's an island," co-author Jason Hofgartner told BBC News.

Hofgartner and his colleges from Cornell University have four different hypotheses that are all "equally preferred. They include: waves, rising bubbles, floating solids and suspended solids.

Titan operates on a 30-year seasonal cycle, and the moon's northern region will likely become a more "dynamic place" as Tian approaches its summer solstice by May 17, according to BBC News.

"Right now, Titan is basically half way between the vernal equinox (August 2009) - at the beginning of spring - and the summer solstice, the start of summer. It's roughly equivalent to what we would consider the beginning of May," said Hofgartner.

"As Titan approaches its summer, more of the Sun's energy is being deposited in the northern hemisphere," he added.

Researchers have already seen evidence of small waves on another Titan sea.

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