Hua Feng was amazed at Yun Meng's inferences about what he had learned, but the following study made Hua Feng more aware of the charm of astronomy. Saturn's gravitational pull causes Titan to constantly rise or squeeze into shape. If Titan were made entirely of solid rock, gravity from Saturn would cause its surface to uplift and form so-called "solid tides," which should be about 3 feet (about 1 meter) high. However, Cassini's measured data shows that the bulge is as high as 30 feet (about 10 meters). This data suggests that the planet Titan is not entirely composed of solid rocky material.

At first, scientists were not sure that Cassini would be able to detect tidal uplift caused by Saturn's gravity. However, the Cassini probe did just that, flying by Titan six times between February 27, 2006 and February 18, 2011, during which time it made precise measurements of Titan's gravity field. These gravitational field data, with the assistance of NASA's Deep Space Network (DSN), ultimately gave an accurate value of the size of Tidal Uplift on Titan's surface.

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From NASA's Jet Propulsion Laboratory (JPL), who is also a member of the Cassini project team, she said: "We did ultra-high-precision measurements, and we were fortunate to have a very stable connection between the Cassini probe and the Deep Space Network antenna.

Tidal uplifts formed by the gravitational forces of Saturn are less significant than those formed on other giant planets, such as some moons of Jupiter. However, in the absence of field drilling conditions, gravity field data is the best way to understand Titan's internal structure. ”

To create a tidal uplift effect of measured size, the ocean layer beneath Titan does not have to be very thick and deep. A layer of liquid water between its hard, deformable shell and the inner rocky mantle layer would allow Titan to orbit around Saturn with the kind of uplift or compression that observations reflect. Since Titan's surface is mostly made up of water ice, which is common in the outer solar system moons, scientists believe that Titan's oceans are also composed mainly of liquid water.

On Earth, gravitational action from the Moon and the Sun causes tides on the surface oceans. In the open sea, this uplift can reach 2 feet (about 60 centimeters). Gravitational pull from the Moon and the Sun can also cause solid tides to form in the Earth's crust with an amplitude of about 20 inches (50 centimeters).

The presence of a liquid ocean beneath Titan's surface does not in itself constitute a conclusion that life may exist here. Scientists tend to believe that life is only possible if there is direct contact between liquid water and rocks. It is not yet possible to confirm whether the bottom of this ocean is made of rocks.

The results of this detection are of great significance for unraveling the mystery of continuous methane resupply on Titan. Methane is abundant in Titan's atmosphere, but researchers believe that methane should be unstable in the atmosphere, and if Titan's atmosphere can remain abundant for a long time, then there must be a source of continuous supply of methane.

Jonathan Lunin

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E), a member of the Cassini Project at Cornell University in the United States, said: "The discovery of a liquid water layer beneath Titan is very important because we want to understand how methane is stored inside Titan and how this stored methane is released. "This is very important because all the unusual things about Titan have to do with the abundance of methane, but the methane gas in its atmosphere should have been destroyed in a geological sense for a short period of time," he said. ”

Imagine an underground ocean of liquid water filled with ammonia that rises along fissures and pores to the surface, releasing methane gas from the ice. At the same time, such an underground ocean could also serve as a methane storage pool.

On October 22, 2012, according to the latest images sent back by NASA's Cassini probe, scientists have identified some huge high-temperature dome-shaped structures on Saturn's largest moon Titan. This is much like what you see when baking bread, when baking is done, the crust of the bread bulges and cracks. Scientists now believe that something similar is happening on Saturn's largest moon.

Scientists have previously observed similar terrain on the surface of Venus, where a tree called Kunapipi (Ku

apipi), the probe photographed a dome-like bulge about 20 miles (30 kilometers) in diameter. The researchers also believe that a narrow rift valley about 70 kilometers long observed on the surface of Titan is also due to surface cracking caused by the upwelling of the underlying material, which may be magma.

"This dome-shaped formation, which we have never observed before on Titan, shows that the planet continues to surprise us even after eight years of exploration," said Rosaly Lopes, radar equipment scientist at NASA's Jet Propulsion Laboratory (JPL) Cassini Project. ”

This unique tectonic topography may be similar to Earth's rock cap, which is formed by the condensation of rising intrusive lava. Mount Henry in the U.S. state of Utah is a prime example of this landform. This image showing the structure of the vault was taken by the Cassini probe on May 22, 2012, using radar equipment.

The other one is led by Ellen Thofen

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The team of Cassini scientists led by Titan scrutinized radar images of Titan's southern hemisphere and found traces of ancient coastlines here. Titan is the only planet other than Earth that has been confirmed to have a stable liquid on its surface, even though these liquids are not water, but hydrocarbons.

The presence of vast oceans has only been observed in Titan's northern hemisphere. However, an analysis of the data collected by the Cassini probe between 2008~2011 shows that there was also a vast shallow sea area near the south pole of Titan.

Dr. Stephens and her colleagues identified traces of two oceans that had dried up or were mostly dry in the southern hemisphere of Titan. At one point, the area of one such dried ocean may have reached the size of 475x280 kilometers, and the depth could have reached hundreds of feet. Lake Ontario (O. Ontario), the largest lake in the southern hemisphere of Titan, is the largest lake in the southern hemisphere

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io Lacus) is located within the confines of a dry ocean, which appears to be the only remaining part of what was once a vast ocean.

And the other was led by Cassini radar team member, Oded Aha of Caltech

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The Ph.D.'s research team believes that Titan is undergoing long-term changes similar to Earth's Milankovitch cycles, which are the result of long-term regularity in orbit. This long-term climatic change will cause Titan's surface fluids to migrate back and forth between its northern and southern hemispheres. According to this model, Titan's southern hemisphere should have had a vast ocean about 50,000 years ago.

"The ocean on Titan's surface is a ready-made laboratory for the chemical environment of pre-life life, and we also know that it is migrating between the northern and southern hemispheres on a cycle of about 100,000 years," said Dr Thofen. "I'd love to take a closer look at Titan's oceans in the northern hemisphere and the dried up marine remnants in the southern hemisphere to see how far these pre-life chemical evolutions have progressed," he said. ”

Cassini's team has largely confirmed the stability of Titan's northern hemisphere ocean system. They have been constantly monitoring the oceans here for the entire Titan-season (about 6 years on Earth). In this image, taken on May 22, 2012, scientists found that the shorelines of lakes in the Northern Hemisphere have not changed, suggesting that lakes in the Northern Hemisphere are not seasonal. In contrast, after a storm in 2010, there was a noticeable darkening near Titan's equator.

It has long been believed that Titan is the largest moon in the solar system and has been named Titan.

In Greek mythology, the Titans were a family of giants. Titan is what scientists believe to be the most likely planet in the solar system to have life outside of Earth. It is the only moon in the solar system with a thick atmosphere. Unlike Earth, where the atmosphere is mostly composed of nitrogen and oxygen, Titan's atmosphere is mostly methane. Moreover, the dense atmosphere reflects most of the light, causing an anti-greenhouse effect, making Titan's surface very cold, with a temperature of -180 degrees Celsius, making it impossible for liquid water to exist.

But in 2005, two teams of scientists suggested that extraterrestrial microbes might live in the liquid hydrocarbons of Titan Lake. Scientists say that acetylene is formed in the atmosphere of the Titan and descends to the surface of the Titan. Alien microorganisms eat acetylene and synthesize with hydrogen to obtain energy.

Since then, dozens of lakes have been discovered on the surface of Titan, which scientists believe are filled with a mixture of liquid ethane and methane. However, since no probe spacecraft has taken direct samples of Titan Lake, no one knows the exact amount of acetylene in it. In 1989, scientists estimated that the amount of acetylene in the hydrocarbon liquid in the Titan Lake was only a few parts per 10,000.

A team of scientists led by Daniel Caudier of the École Nationale Supérieure des Chemistries in Rennes, France, has made a new calculation of the acetylene content of the Titan Lake. Based on newly obtained data from the Cassini-Huygens mission to explore the Saturn system, they made an updated estimate that the Titan Lake contains more acetylene. If alien creatures are present on Titan, the acetylene inside the lake is enough to feed any hungry alien creatures.

In 2005, Cassini's Huygens probe landed on Titan, which is filled with liquid methane. Huygens was working 24 hours on Titan, focusing on detecting possible signs of life on Titan.