The crash of the lunar probe left tardigrades on the moon. Will these creatures dominate the moon?

If you ask which creature on Earth has the most tenacious vitality, then the tardigrade is definitely the undisputed champion.

Tardigrades generally refer to water bears, which are very tiny tardigrades with a maximum body length of no more than 1 mm. Without a microscope, we would hardly notice them. Such a seemingly inconspicuous little creature has extremely tenacious vitality. Observational studies have shown that tardigrades have a strong tolerance to temperature. The extreme temperature they can endure is as high as 151°C and as low as -272°C. Tardigrades not only have a strong tolerance to temperature, but are also able to withstand pressure. Even 6 times the pressure on the seabed cannot kill them. In fact, tolerance to temperature and pressure is nothing. Even in an oxygen-deficient, high-radiation environment, tardigrades can still survive.

In 2007, a space experiment was conducted in which tardigrades were exposed to the vacuum environment of space. After 10 days, most of the tardigrades were still alive, which is difficult for any other known life form to do.

Tardigrades are so tenacious that some people think: "If this creature is thrown to other planets, it will surely be able to thrive there, right?" Before 2019, this was just a fantasy, but an accident in 2019 made this fantasy a reality. The moon is the satellite of the earth and the first extraterrestrial planet explored by humans. To this day, human beings' enthusiasm for the moon has not diminished at all. Many countries are keen on exploring and studying the moon, and Israel is no exception. Israel has an organization called "ArchMission Foundation", which plans to send a probe called "Genesis" to the moon in 2019.

The plan went as planned. On February 21, 2019, the Genesis was successfully launched and took off. It took more than a month to successfully enter the lunar orbit, but then an accident happened.

On April 12 of the same year, Genesis was preparing to land on the surface of the moon, but the main engine failed. As a result, Genesis fell uncontrollably and eventually crashed on the surface of the moon. Although Genesis crashed, some things were left on the moon, and these things were still active, they were tardigrades. On Genesis there was a disc that recorded data and information of human civilization, called the "Lunar Library". In addition to this disc, Genesis also carried thousands of tardigrades, some of which were directly distributed on the surface of the disc, and the other part was sealed with epoxy resin.

The lunar probe crashed. Can the tardigrades survive? No problem.

The strong survival ability of tardigrades is also reflected in their impact resistance. Experiments show that they can withstand impacts of about 900 meters per second, while the speed of the lunar probe crashed was 139 meters per second. It is believed that most tardigrades can survive. Tardigrades were left on the moon, so many people began to care about the future of these tardigrades, and even imagined a science fiction story based on this: these tardigrades multiplied on the moon, and more and more of them eventually occupied the moon and bred wisdom and civilization through continuous evolution, and finally competed with humans. This is a good story, but is it possible in reality? Not likely.

Tardigrades do have strong survival abilities, but their strong survival abilities are achieved through "cryptobiosis".

What is cryptobiosis? When tardigrades are in a harsh environment, they will dehydrate their bodies. The water content of tardigrades in a normal state is about 85%, and after dehydration, their body water content will drop to 3%. At this time, the body of the tardigrade will shrink and no longer move. This form is called cryptobiosis. Tardigrades in a cryptobiosis state can withstand various harsh environments. The tardigrades carried by the Genesis had already entered a cryptobiosis state before departure. The environment on the moon is extremely harsh. There is no atmosphere, the temperature difference between day and night is extremely large, and it is exposed to cosmic radiation, so the tardigrades left on the moon will not be released from the cryptobiosis state.

If the tardigrade remains in a cryptobiotic state, it will not be able to reproduce, and even if it can survive, it will not be able to develop further on the moon.

In fact, even tardigrades in a cryptobiotic state can hardly survive for a long time on the moon. Although tardigrades can tolerate high and low temperatures, they are limited in time. For example, under extreme conditions of 151°C and -272°C, they can only survive for a few minutes. Although the temperature on the moon is not so extreme, the temperature can reach over 100 degrees in places directly exposed to the sun, and at night, the temperature may be close to -200°C, so over time, tardigrades will gradually die. It seems that the moon is really a purgatory for life forms. Even as tenacious as tardigrades, it is difficult to survive on it for a long time. Of course, there may be an exception, that is, tardigrades enter the surface of the moon due to the impact during the fall. If so, they may survive there. As for how long they can survive, it can only be verified in the future.

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