Titan, Saturn's largest moon, is home to a mysterious "magic island" that appears and disappears into the satellite's pungent chemical seas. Now, researchers have outlined their best guesses as to what this island may actually be.

A study published in the journal Nature Geoscience details how experts first noticed the "island" during a flyby of the Cassini spacecraft back in July 2013. It appeared as a bright splotch floating in the Ligeia Mare - Titan's second largest body of the methane and ethane liquid that make up its seas. Sixteen days later, during a second pass, the spacecraft showed that the "island" had vanished.

"'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," study co-author Jason Hofgartner told BBC News.

Instead, he and his team focused on more realistic explanations for this mysterious formation's vanishing act.

"We suggest that these bright features are best explained by the occurrence of ephemeral phenomena such as surface waves, rising bubbles, and suspended or floating solids," the authors of the study write, adding that this phenomenon may even be seasonal - more likely to occur during a change in Titan's sea-flow cycle affected by the Sun.

Observing surface changes associated with changes in the distribution of solar energy across Titan, researchers using Cassini data have theorized that Titan is currently between the beginning of spring and the summer solstice.

"Its roughly equivalent to what we would consider the beginning of May," Hofgartner said.

As Titan begins to slip into the summer season, the researchers believe that wave activity will increase, potentially becoming so violent that they show up as island-like formations in the small glimpses Cassini grabs of the moon as it flies by.

This activity might also disturb floating icebergs that commonly sit along the edges of the Mare, or organic compounds with a density low enough to be able to float on the moon's methane seas.

Lastly, the "magic island" could simply be bubbles. Volcanic activity, the researchers say, while difficult to detect, is a very real possibility - launching bubbles from a subsea vent.

Cassini "observes" Titan's surface using a complex radio signaling system to map out geographic features. You can watch a video of what has been mapped so far (including the Ligeia Mare) below.

[Credit: NASA JPL]