In addition to the earth, there may also be life on Titan, and all the creatures on it are slow sloths.

In addition to the moon, Mars, and Venus in the solar system, human probes have also successfully landed on another planet, which is Titan, known as "Titan." In 2005, the Huygens probe successfully landed on a plain on Titan and took a blurry photo full of "pebbles". In 2027, the United States plans to launch the "Dragonfly" nuclear-powered unmanned aircraft to explore Titan again. Why are humans so interested in this distant planet? Because it is the second most likely place for life in the solar system after Earth.

Titan is the second largest satellite in the solar system. Its surface is covered with a dense yellow atmosphere and the sunlight is very low, but its interior may be full of life. Its atmosphere is mainly composed of nitrogen, with small amounts of methane, hydrogen and other trace gases, and it spins faster than the star itself. Its star is half ice and half solid material, and its core is as hot as the Earth's core. Since it spends 95% of its time within Saturn's magnetosphere, it is protected from the influence of the solar wind. These are the basic conditions for the formation of life.

A small amount of solar wind converts trace amounts of methane in Titan's atmosphere into hydrocarbons. The detector also found polycyclic aromatic hydrocarbons and propylene in its atmosphere. Although these things are just compounds, their appearance shows that this planet has the ability to synthesize some more complex things. Second, like nutrient solution in a petri dish, they can provide a foundation for the emergence of life. In addition, scientists speculate that there may be an organic chemical substance called "tholin" on the surface of Titan.

The environment on Titan is very different from that on Earth. Its surface temperature is only -179 degrees Celsius, which is very cold. However, under the ice shell, there may be a warmer global methane ocean, which contains conditions suitable for the survival of microorganisms. Although there is carbon and water (ice) on Titan, the life forms on it may be completely different from the carbon-based life on Earth. Scientists speculate that it should be based on liquid methane.

Such organisms inhale hydrogen instead of oxygen, use acetylene instead of glucose for metabolism, and exhale methane instead of carbon dioxide. All life forms on Earth (including methanogens) use liquid water as a solvent, and it has been speculated that life on Titan may use liquid hydrocarbons such as methane or ethane for dissolution. Since the dissolution efficiency of methane and ethane is much lower than that of water, and because the presence of a large amount of ammonia will cause chemical reactions to proceed more slowly, life on Titan may be slow, just like "Zootopia" Just like Mr. Sloth in the movie.

Titan can be regarded as a time machine, helping us understand the earliest conditions of the earth and uncover the mystery of how life on earth was born. In the distant future, as the sun will become a red giant, the temperature on Titan may increase and the environment will become more habitable. This is enough time for life on the planet to upgrade, and for us humans, Titan may also be our next stop.