Specialized media have repeatedly talked about the resistance of tardigrades to extreme conditions like the vacuum of space, temperatures near absolute zero, and a critical scarcity of water and food. But a recent study by researchers from the Universities of Oxford and Harvard indicates that they will also survive different global sterilization events, resisting even until becoming the last life form on the planet. The only thing that can completely annihilate them is the fury of our dying Sun.
The human species is very fragile. Any abrupt change in temperature, lack of water or food, disease, excess or deficit of pressure, and high levels of radiation could prematurely end our story. An old saying goes that necessity is the mother of all invention, and with each new challenge, humanity has found a way to adapt, but there are certain conditions that demand much more than a technological solution. A recent study published in the PNAS suggests that the so-called “sixth extinction” has already begun, however, there is an animal that could shake off that event as if it were dust: the tardigrade.
What Would It Take to Wipe Them Out?
According to the work resulting from the most recent collaboration between Harvard University and the University of Oxford, tardigrades will easily avoid not only “local” extinctions, but also astrophysical catastrophes such as the impact of an asteroid, a supernova, or a gamma ray burst. The key to destroying tardigrades is the absolute disappearance of the oceans, and the only thing that could develop such an event within a few billion years is our Sun.
Only two asteroids are known in our solar system, Vesta and Pallas, with enough mass to evaporate all of Earth's water through an impact. A supernova would have to occur less than 0.13 light years away to achieve the same (remember that Proxima Centauri is 4.22 light years away), and gamma ray bursts, beyond their lethal potential, are very rare and too far away: one would be needed at 45 light years. In summary, the probability that a catastrophic event ends life on Earth including tardigrades before the Sun evaporates the oceans is one in a million. That would indicate that once established, life in general would be very difficult to completely eliminate.
