Have you ever wondered if there are other planets in the solar system that can have liquid rivers, lakes, and oceans like Earth?Have you ever wondered if there are strange life forms or other surprising phenomena in these liquid waters?If you are interested in these questions, then you must not miss Titan, the largest moon of Saturn and one of the most mysterious planets in the solar system.
Titan is the only known moon in the solar system with a dense atmosphere, and its surface atmosphere is about 60% higher than that of Earth, and the pressure on the surface of Titan is equivalent to 15 meters at the bottom of the sea. This thick orange atmosphere, composed mainly of nitrogen and methane, contains many organic molecules, that is, compounds that contain the element carbon. These organic molecules are constantly undergoing complex chemical reactions in the atmosphere, forming a variety of organic matter, some of which will fall on the surface of Titan in solid form, and some will form clouds in the atmosphere, and then it rains, but instead of water, it will rain in liquid methane and ethane.
Yes, you heard it right, the rain on Titan is made up of methane and ethane, and this is because the surface temperature of Titan is very low, about minus 180 degrees Celsius, and at this temperature, water turns into hard ice, while methane and ethane turn into liquid. These liquid methane and ethane, like water on Earth, form rivers, lakes, and oceans on Titan's surface, and even have waves and tides. Titan is the only planet in the solar system known to have a similar Earth-like circulatory system, where liquid rains down from the clouds, flows over the planet's surface, then fills lakes and oceans, and finally evaporates back into the sky and continues the cycle.
On Titan's surface, in addition to waters with liquid methane and ethane, there are many black organic dunes, which are made up of organic solids that fall from the atmosphere and cover most of Titan's landmass. Titan's topography is very complex and diverse, with mountains, plains, canyons, volcanoes, glaciers, etc., and there is even strong evidence that there is a layer of liquid water under Titan's crust, which may be the best place for life on Titan.
The wonders of Titan don't stop there. In 2014, NASA's Cassini-Huygens probe, using radar to detect Titan's Arctic region, discovered a surprising phenomenon: on the surface of Titan's largest ocean, the Kruger Sea, there are some bright spots, which appear from time to time, sometimes only for a few hours, sometimes for weeks or more. These bright spots, like islands that suddenly appear and then disappear, are therefore called "magic islands" by scientists
What exactly are these "enchanted islands"?Why do they appear and disappear?What do they have to do with Titan's organic cycle?These questions have always puzzled scientists, and they have also attracted countless curious eyes. In order to solve this mystery, scientists have made a variety of hypotheses and simulations, some believe that the "magic island" is an illusion caused by waves, and some believe that the "magic island" is a real island composed of solids suspended in water, solid floating on the surface of the water, or bubbles of nitrogen. However, none of these hypotheses were conclusively proven, until recently, a new study, gave a more likely answer.
The study's lead author, Xinting Yu, an assistant professor in the Department of Physics and Astronomy at the University of Texas at San Antonio, a planetary scientist from China who was curious and enthusiastic about Titan's "enchanted islands" and wondered if the cause of the mysterious islands could be found out by taking a closer look at the relationship between Titan's atmosphere, liquid lakes and solid materials deposited on the moon's surface.
"I wonder if the Enchanted Island is made up of organic matter, like pumice stones on the earth, that can float on the water for a while and then sink back," Yu said. ”
To test her idea, she and her team used computers to simulate Titan's organic cycles, analyzed different possibilities, and finally came to a convincing conclusion: the "Enchanted Island" may be made up of holes, frozen organic matter, like organic icebergs.
Yu Xinting explained that there are many kinds of organic molecules in Titan's upper atmosphere, which can clump together, freeze into clumps, and then fall to the surface of the satellite, including rivers and lakes where the waves are only a few millimeters high for liquid methane and ethane. These organic clumps, some of which are dense and some of which are porous, are like cheese. What would happen to these organic clumps if they fell into Titan's hydrocarbon lakes?
Yu and her team found that if organic clumps are dense, they will quickly sink to the bottom of the lake because they are much denser than liquid methane and ethane, and the surface tension of methane and ethane is so low that it is not easy for solids to float. However, if the organic clumps are porous, then the situation is different, their density will be reduced, and the liquid methane and ethane will slowly seep into their holes and thin tubes, which will increase their buoyancy and allow them to float on the surface of the water for a while, like organic icebergs.
Of course, these organic icebergs don't float on the surface of the water forever, they gradually dissolve or sink into the water over time, which explains why the "Enchanted Island" disappears from time to time. So, where do these organic icebergs come from?Yu Xinting and her team believe that they may have been formed by organic sand dunes or glaciers along the coast, and when the organic sand dunes or glaciers are washed by water or blown by the wind, some of the debris will fall off and then float into the water, forming "magic islands". These debris, if large enough and with suitable holes and thin tubes, can remain on the surface of the water for a while until they are destroyed or disappear.
In addition to the "Enchanted Island", there is another strange phenomenon on the oceans and lakes of Titan, and that is that their surface is very smooth, there are almost no waves, and if there are, they are only a few millimeters high. This is in stark contrast to the oceans and lakes on Earth, where the waters of the Earth, affected by wind, tides, topography and other factors, produce waves of various sizes, and sometimes even giant waves and tsunamis. So, why are the waters of Titan so calm?Yu Xinting and her team came up with a possible explanation, which is that Titan's oceans and lakes are covered with a thin layer of organic solid ice, which acts like a protective film to counteract the effects of wind and tides and keep the water surface smooth. This layer of ice, which may also be formed by organic solids falling from the atmosphere, condenses on the surface of the water to form a thin cover.
Through this research, Yu Xinting and her team may have solved two mysteries of Titan, namely the "magic island" and the smoothness of the waters. These two mysteries are related to the organic cycle of Titan, and also reflect the complex and diverse landforms and climates of Titan. List of high-quality authors