Mysterious 'magic' islands that come and go on Saturn's moon Titan finally have an explanation

An artist's rendition of Titan's landscape features a hazy atmosphere, dark dunes, and mirror-smooth lakes and seas that resemble Earth's. On these bodies of liquid hydrocarbons, new research suggests that the appearance of "magic islands" may be caused by floating organic solids. (Image credit: NASA/JPL)

Saturn's moon Titan may be known for its methane lakes, but it also has "magic" islands — mysterious bright spots atop the lakes that come and go, with no known explanation. However, a new study, published Jan. 4 in the journal Geophysical Research Letters, proposes a surprisingly simple explanation for the magic islands: They're floating chunks of frozen organic material.

"I wanted to investigate whether the magic islands could actually be organics floating on the surface, like pumice that can float on water here on Earth before finally sinking," study lead author Xinting Yu, a planetary scientist at the University of Texas at San Antonio, said in a statement.

Yu wondered what would happen if clumps of that atmospheric haze fell into the lakes. Would they float or sink — or perhaps even float for a while before eventually succumbing to the liquid, just like the magic islands?

"For us to see the magic islands, they can't just float for a second and then sink," Yu said. "They have to float for some time, but not for forever, either."

The researchers used physics and chemistry calculations to determine what happens to particles when they hit the lake, and, if they didn’t sink, how long they’d stay afloat. They found that the clumps of solids wouldn't dissolve in the lakes. But they would also be too heavy to float — that is, unless they were extremely porous, full of holes just like the pumice stones Yu imagined.