Infrared image of Saturn’s icy moon Titan
NASA/JPL-California Institute of Technology/Stephane Le Mouerik, Virginia Pasek
Saturn’s moon Titan is home to strange “magical islands” that appear and disappear over the course of hours to weeks. These so-called islands are actually porous, sponge-like masses of snow that can slowly fill with liquid before sinking.
Titan’s thick atmosphere is filled with complex organic molecules that can clump together and fall to the moon’s surface like snow. Sintin Yu Researchers from the University of Texas at San Antonio thought that snow could be the cause of the magical islands. To test their idea, they took advantage of what we know about these atmospheric compounds and how they are expected to interact with Titan’s oceans.
Titan’s liquid is methane, not water, so any solids on the surface of these oceans would normally be expected to sink quickly. Water molecules tend to stick together and displace other substances, but methane easily sticks to other molecules, so the surface tension of a pool of liquid methane is very low.
“Water molecules just love themselves by excluding certain molecules,” he says. michael marasca from NASA’s Jet Propulsion Laboratory in California was not involved in the study. “But if you put methane on the same surface, it’s going to start crawling all over the place.” That means Titan’s methane oceans and lakes should immediately engulf even the solids that are expected to float. It means that.
But that clearly won’t happen on the magical island, which appeared as a temporary bright spot in observations from the Cassini spacecraft. “For us to see magical islands, they cannot float briefly and then immediately sink,” Yu said in the paper. statement. “You have to stay afloat for a while, but not forever.”
Researchers have found a solution to this problem. When large amounts of snow accumulate on the coast, they can form sponge-like, porous ice. Once these porous “icebergs” separated from the land, they could float in Titan’s oceans for long enough to rival Cassini’s observations. The researchers calculated that this would work if the sponge-like structure contained enough free space (at least about 25 to 50 percent, depending on the exact composition of the ice).
However, this does not mean that these mysterious islands are definitely porous icebergs. “We’re narrowing down different scenarios for the magical island, but we don’t know the answer yet,” Malasca says. Other possible explanations include nitrogen gas bubbles, waves caused by wind or solid ocean deposits. However, this provides evidence that Titan’s temporary islands may actually be suspended matter from this strange world’s atmosphere.
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