'Magic islands' on Titan look like Swiss cheese. They are simply snow clusters

The floating "magic islands" of Titan, Saturn's largest moon, have long intrigued scientists. But a new study now seems to clear the air over these islands and what constitutes them. Shaped like a honeycomb, and sometimes even resembling Swiss cheese, these islands on Titan are simply glacier-like snow clusters. 

The latest revelations about Saturn's moon Titan were made in a study published in Geophysical Research Letters journal.

The Cassini-Huygens spacecraft was the first to observe these so-called islands. The Saturnian moon is filled with liquid methane and ethane lakes and these islands looked like shiny, moving spots above these lakes. However, they weren't always visible and vanished from time to time.

Xinting Yu, an assistant professor at the Department of Physics and Astronomy at the Univerisity of Texas, led new research on Titan's magical islands, which suggests that they are "floating chunks of porous, frozen organic solids in shapes similar to honeycomb or Swiss cheese." They likely stash after it snows from the sky of Titan, a moon larger than Mercury. 

Titan's atmosphere, rich in methane and other organic molecules, is 50 per cent thicker than Earth's. The thick, upper atmosphere clumps together, freezes, and snows onto the surface and into the lakes of methane and ethane due to the presence of organic molecules. 

As the liquid bodies on Titan's surface are already packed with organic molecules, the complex organic "snow" molecules do not dissolve as soon as they hit them. "For us to see the magic islands, they can't just float for a second and then sink. They have to float for some time, but not for forever, either," Yu said.

The hollow holes and tubes in the snow clumps would allow them to float if they were large enough or porous until methane or ethane oozed inside, causing them to sink after filling the voids. 

However, according to the model by Yu and her colleagues, the snow clumps would be too small to let this mechanism happen. But enough of this snow clustered on the lakeside shores, large pieces could break off and float on the lakes of methane and ethane, similar to how ice sheets break from glaciers and float on the surface of the seas on Earth. This mechanism is known as calving. 

Yu and her team have also explained another enigma on Saturn's Titan about the peaceful liquid bodies with waves no bigger than a few millimetres. According to the study, a floating blanket of frozen solids covers the surface of liquid bodies on Titan, granting them smoothness.