Record the world where the rain stays, collects in lakes and ponds, enters the surrounding rock and evaporates, only to fall again. There is only one catch: the world is Saturn's moon, Titan where rain is not water; it is liquid methane.
Two new documents reveal how this gently known "water cycle" is expressed on the surface of Titanium. To do this, two separate research groups contacted Cassini mission data which ended their presence in the Saturn system . September. . The spacecraft flew more than 100 times in the past through a huge moon and gathered important observations of this strange world as it did.
Some of these comments have shown scientists something really extraordinary: the first look at the liquid at the moment on the landscape, not just the ghosts of such liquid properties . "Titan is the only world behind the surface where we see liquid bodies on the surface," Rosaly Lopes, a scientist at the planet Jet Propulsion Laboratory at NASA, who worked on Cassini's mission but did not participate in any of the new documents. "Some of us like to call Titan on the Earth's external solar system."
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"Titanium is the most interesting moon of the solar system. I think this is causing enemies, but I think it's really true, ”said Shannon MacKenzie, one of the new research and planetary scientist at John Hopkins University's Applied Physics Laboratory, said Space.com. But that doesn't mean the moon is simple. "Titan throws us a lot of curveballs," she said.
The MacKenzie study analyzes one possible curveball: three small features that appeared to be liquid-filled lakes when Cassini first noticed them but seemed to have dried up until the spacecraft returned to the territory . Observations indicate that the liquid evaporates or soaks into the surrounding surface of the planet.
These "phantom lakes" may be evidence of seasonal changes on the moon, MacKenzie and its collaborators believe. (Between the spacecraft's two-space observations, during which the northern hemisphere hovered from winter to spring, seven Earth years passed.)
But the situation may not be as simple as two observations of different measures were taken. Cassini has been designed to collect data with its radar device or its video and infrared camera, but not simultaneously. And during the first edition of the spacecraft, the region was too dark to use the cameras.
MacKenzie and her colleagues had to consider a possible variable. But she is still convinced that something is different in both passages, and that it is likely that fluid was there, then disappeared. Even though different signals over two flybys were due to another phenomenon, MacKenzie said she was still intrigued by what could tell us about the strange moon, one of the scientists' trusted candidates, where life can be hidden behind the earth. [1
However, although MacKenzie focused only on three small lakes that seem to have disappeared, many lakes remained visible through the Cassini region. In a second document published today, scientists used radio data to explore many many larger lakes.
Last Cassini last titan in 2017 April The spacecraft was programmed to collect a very specific type of data called altimetry. Measure the height of different materials above the lake area. Caltech's planetary scientist Marco Mastrogiuseppe has already used similar data to measure the depths of some of the Titanic marine and the Cassini team expected it to be able to do the same with lakes
Mastrogiuseppe and his colleagues did this in their new book, pointing out that the bottom of the lakes is more than 100 meters deep and found their content dominated by the liquid method . "We realized that the lakes were basically very, very similar to the sea," he said. "We believe that these bodies are nourished by local rain and then by these pools, they drain the liquid."
This indicates that below the surface of the Titan the moon can hold another Earth impression: a cave. On the Earth, many caves are made up of water that dissolves the types of surrounding rocks, such as limestone, leaving karst landscape characterized by springs, aquifers, caves and shells.
I think they see similar karst type properties. Also, they have not noticed channels linking all these different fluid properties so Mastrogiuseppe and others suspect that some liquids can soak into the surrounding area, just like a karst system
. "Titan is really this world that is geologically similar to Earth, and exploring the interaction between liquid bodies and geology is something we couldn't really do," Lopes said. New research is beginning to do this by seeing that these interactions live in another planetary body.
Of course, it is much more difficult to explore these interactions so far in a world that has never been the focus. mission. "We talked about possible missions with robotic scientists who could scroll to lava pipes and caves on the moon and Mars," Lopes said. "Can we send one of them in the future to scan this area and into the cave and find out what's here?"
Such a mission is unlikely to happen again, but NASA is seriously considering a project called Dragonfly ] who would land a drone on a strange moon. After the mission, it will start operating in 2025. And nine years later, he will reach Titan. And if NASA doesn't choose Dragonfly, there is a chance that another mission concept will come. "Titan just cools down," MacKenzie said.
And MacKenzie and Mastrogiuseppe documents were published today (April 15) in Nature Astronomy.