Because this is a lie to you.
Starting with some foreign media that are not surprisingly deadly, some media practitioners concoct wrong memes on "the vitality of slow animals" to attract attention, and then many people spread the wrong memes indiscriminately and increase the number layer by layer, as is the case all over the world.
Typical exaggerations in 2017:
The description of the "water bear insect cryptogenesis can recover in 120 years" is a misconception: it is actually just a few twitches on one leg after soaking in water.
The total lifespan of tardigrades in the non-cryptophytic state is only two to three years, and the tardigrades in the cryptogrown state at room temperature have the probability of lasting up to ten years before waking up, and there is also a probability of dying, and the tardigrades that have been cryptogytic for more than ten years at room temperature have never successfully awakened in the laboratory. Continuous cryopreservation of tardigrades behaves similarly to nematodes in this regard, with a limit of about 30 years.
"Having all four kinds of cryptospans" sounds like "adaptability is very strong", but if you think about whether these items are "the creatures of nature can add a little selection one by one" or "people summarize them for convenience when observing their traits".
Typical exaggerations for 2019:
Scientific experiments heating a group of tardigrades in a container prove that an environment of 82.7 degrees Celsius kills half of the cryptobizoic tardigrades in an hour, and an environment of 63.1 degrees Celsius kills half of the cryptobizoic tardigrades in one day.
The experiment did not stop near the temperature of the sauna. They went on to verify that an environment of 37.1 degrees Celsius killed half of the non-cryptosotic tardigrades that had not adapted to the heat in two days, and that adapting would raise the temperature needed to die half the time in two days to 37.6 degrees Celsius [1]. This temperature is no higher than your body temperature, which means that the global warming heat wave set off by humans can completely kill tardigrades in many places on the surface.
In 2019, an Israeli lunar probe crashed on the surface of the moon with tardigrades, and a large number of boring memes appeared on the Internet. Some equally bored researchers came forward and experimented to see if this would kill tardigrades, only to find that an impact velocity of more than 900 meters per second would shatter the tardigrades in an occult state into a paste and die thoroughly.
Figure c: Impact result at 728 meters per second; Figure d: Impact result at 901 meters per second
In contrast, experiments have shown that common bacterial biofilms can withstand direct attack from ceramic particles at a rate of 5,000 meters per second, and that none of the bacteria at the point of impact will die [3]. Caenorhabditis elegans can withstand accelerations of 400,000 times the acceleration of gravity, the same as E. coli.
Atypical exaggerations:
Touting fragile, dreamlike creatures like tardigrades as "incapable of hunting, and ignorant of the fact that a variety of Earth creatures survive in space for a long time.
- After tardigrades are exposed to space and lose their supply of foreign oxygen, they can only move for a few minutes to a few days, and then can only wait for the environment to get better in the "cryptobiosis state" where their metabolism has basically stopped.
- In the 2007 Russian experiment, the so-called tardigrades that can be revived after 10 days of exposure to space are relatively better partially obscured by human spacecraft, and the recovery rate of the part exposed to solar radiation is low and the fertility is impaired.
- Microbes from Earth still exist in the thin atmosphere beyond the Carmen line. The Carmen Line is recognized as the dividing line between outer space and the Earth's atmosphere, at an altitude of 100 kilometers. Some microorganisms float in the atmosphere at altitudes of 48 to 77 kilometers for a long time, and atmospheric movement can occasionally take them beyond the Carmen line.
- Russian astronauts have discovered marine microorganisms from Earth on the shell of the International Space Station. Russian rockets carrying this module have never flown low above the ocean. Astronauts estimate that the microbes were brought into space by an occasional air stream and attached to the space station, amplifying in a vacuum.
- Japanese scientists placed radiation-resistant Kiwi cocci outside the Japanese experimental module of the International Space Station for 3 years, and the results of the experiment showed that the bacteria in the clot with a thickness of more than 0.5 mm survived. The researchers noted that the bacteria located on the outer surface of the clot died, and their corpses provided protection for the living bacteria below. The researchers estimate that bacterial clumps larger than 1 millimeter in diameter could survive in space for 8 years, and thicker clots could survive in space for 15 to 45 years. This time span allows the splashing rocks produced by celestial impacts to carry microbes through the solar system — and doesn't require large rocks to protect them.
- More experiments on the International Space Station have shown that bacteria that are much more mundane than the guys above can survive in space for a long time when they are clustered, such as Bacillus subtilis and Escherichia coli.
- Thermophilic cyanobacteria species Chroococcidiopsis, which produces organic matter from photosynthesis, and Xanthoria elegans, can survive in space exposed to space, perhaps helping humans to live in space for a long time.
Absolute zero is out, showing that we really need to increase our investment in teaching physics in junior high schools now.
Some technology journalists and some users of marketing accounts do not have enough knowledge and no scientific spirit, and go with the flow, creating and disseminating this kind of spam.