The “magical island” on Saturn’s largest moon Titan may finally have a scientific explanation. Scientists believe these are glacier-like snow masses shaped like honeycombs.
The so-called islands were first discovered in 2014 when the Cassini-Huygens spacecraft peered through the orange haze surrounding Titan, a moon larger than Mercury. These islands, which appear as moving bright spots on Saturn’s moons above lakes of liquid methane and ethane, have left scientists struggling to explain them. From observation to observation, no one could understand how these temporary blocks appeared and then so easily disappeared.
But new research led by Xin-Ting Yu, assistant professor in the Department of Physics and Astronomy at the University of Texas at San Antonio, shows that these magical islands are actually porous, frozen organic solids shaped like honeycombs or Swiss cheese. This suggests that it is a floating mass. Presumably, the solids accumulate after snow falls from Titan’s skies.
“I wanted to investigate whether the magical island could actually be an organic material floating on the surface of the earth. Like pumice, it can float on water on Earth and then eventually sink. ,” Yu said. said in a statement.
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Titan’s magical islands are real after all
The theories that have been developed to explain Titan’s magical islands fall into two broad categories. On the other hand, some opinions suggest that the island is something like a fantasy. On the other hand, some argue that they must be real bodies.
Included in the phantom category is the suggestion that these islands may have been caused by lunar methane or waves in Lake Ethane, or perhaps by bubble chains associated with material bubbling beneath these liquids. There is.
But when Yu decided to take a closer look at how the moon’s atmosphere, which is 50% thicker than Earth’s and rich in methane and other organic molecules, and its liquid lakes were related, Yu realized that Titan’s magic We discovered that the islands were clearly not an illusion. And on its surface are dark dunes of organic matter.
Titan’s upper atmosphere is dense with organic molecules that clump together and freeze, dumping snow on the moon’s surface and the placid rivers and lakes of methane and ethane that punctuate views of this alien creature.
To see if this was the cause of the magical island, the research team first needed to find out whether Titan’s complex organic molecular “snow” melts as soon as it hits liquid lakes and rivers. . The researchers determined that this dissolution could not occur because these liquid bodies were already clogged or “saturated” with organic molecules.
The next question Yu wanted to answer was, “What happens to these liquid blobs when they hit them?” Will it sink or float?
“To see the magical islands, you can’t just float for a moment and then sink. You have to stay afloat for a while, but not forever,” Yu said.
At first glance, the Titan model seems to suggest that solid objects sink quickly. Ethane and methane in the liquid region of Titan’s surface have a low surface tension, and the frozen solids have a high density. This means that these frozen substances do not float around long enough to be mistaken for islands, magical or otherwise.
But the researchers say there is a mechanism that allows these snowflakes to float in liquid lakes of methane and ethane.
If the snowpack is large enough and porous, like Swiss cheese, it has hollow holes or tubes that allow it to float until methane or ethane seeps inside, fills the voids, and sinks. can.
The model developed by Yu and her colleagues suggests that this would never happen because the individual snow chunks are too small, but if this enough snow were to collect on Titan’s lakeshore, large pieces would It can shatter and fall, floating on top of the methane. Lake Etene.
This is similar to how sheets of ice break off from Earth’s glaciers and float into the ocean, a process called differentiation.
Yu and his colleagues also provided an explanation for another of Titan’s mysteries: why Titan’s liquid body is so gentle in waves of just a few millimeters.
She and her team determined that this is because the surfaces of these liquids are covered with a microscopic suspended blanket of frozen solids, giving them their smoothness.
The team’s research was published in the journal On Thursday (January 4). Geophysical Research Letters.