Titan's 'magic islands' are likely to be honeycombed hydrocarbon icebergs, finds study

A recent research concludes that Titan's "magic islands" are probably floating bits of porous, frozen organic materials, reversing earlier findings that suggested they were gas bubbles. Geophysical Research Letters released the research.

Titan, the biggest moon of Saturn, is covered in a fuzzy orange atmosphere that is 50% thicker than Earth's and full of methane and other chemical compounds based on carbon. Its surface is covered with seas of liquid ethane and methane, as well as black dunes of biological debris. Even more bizarre are what appear to be moving bright patches on the sea's surface in radar footage, which can last for a few hours to many weeks or longer.

Since the Cassini-Huygens mission's initial discovery of these transient "magic islands" in 2014, researchers have been attempting to identify them. According to earlier research, they may be actual islands composed of floating or suspended substances, bubbles of nitrogen gas, or phantom islands created by waves.

Lead author of the new study Xinting Yu is a planetary scientist who questioned whether a deeper examination of the connection between Titan's atmosphere, liquid lakes, and solid minerals deposited on the moon's surface may explain the origin of these enigmatic islands.

"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," Yu explained.

An odd universe of plants

The upper atmosphere of Titan is rich in various organic compounds. The molecules have the ability to group together, freeze, and fall to the moon's surface, where they may land on its amazingly smooth liquid ethane and methane lakes and rivers, which have waves that are only a few millimeters high.

Yu and her colleagues were curious in what would happen to these organic clusters when they got to Titan's hydrocarbon lakes. Would they float or sink?

The scientists looked at whether Titan's organic solids would just dissolve in the methane lakes of the moon in order to arrive at an answer. When the falling materials hit the liquid, the scientists found that they would not dissolve since the lakes are already saturated with organic particles.

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

Methane and ethane, which have low surface tension and make it more difficult for solids to float, make up the majority of Titan's lakes and seas. Unless the clumps were porous like Swiss cheese, the models indicated that the majority of the frozen materials were too thick and the surface tension was too low to form Titan's enchanted islands.

The researchers discovered that liquid methane might seep in slowly enough for the frozen clumps to remain at the surface if they were large enough and had the proper ratio of holes to narrow tubes.

According to Yu's modeling, individual clumps are probably too tiny to float on their own. However, bigger pieces may break off and float away if enough clumps massed along the beach, much like glaciers calve on Earth. These organic glaciers have the potential to explain the phenomena of magic islands if they have the proper porosity and larger size.

Titan's lakes and oceans may have a thin layer of frozen materials covering them, which might account for the extraordinary smoothness of the liquid bodies in addition to the magic islands. Thus, two of Titan's riddles may be explained by the study's findings.