Scientists at the University of Kent in the United Kingdom found out how much tardigrades, microscopic invertevrates that are considered the toughest creatures on the planet, can withstand through a space impact test.
Astrochemistry Alejandra Traspas and the astrophysicist Mark Burchell, were in charge of carrying out the experiment, by means of which they used a two-stage gas cannon that is normally used to experiment with hypervelocity.
This cannon accelerates the projectiles through a double process, first with gunpowder and then with a light gas, such as hydrogen or helium, subjected to rapid pressurization, which allows the projectile to reach speeds of up to eight kilometers per second.
Several tardigrades frozen to hibernation were loaded into nylon shells, which were in turn loaded into the weapon.
After being fired, the projectiles struck sand targets in a vacuum chamber at speeds between 0.556 and 1 kilometer per second. The tardigrades were then isolated and observed to determine how long they needed to awaken from hibernation after impact, compared to other tardigrades that had also been frozen but hadn’t fired the cannon.
The animals were found to survive up to an impact speed of 825 meters per second, but took longer to recover than their non-shot congeners, suggesting they suffered internal damage.
“In shots up to and including 0.825 kilometers per second, intact tardigrades were recovered after the shot, but in higher velocity shots only fragments of the tardigrades were recovered.”, the researchers noted in an article in the journal Astrobiology.
These microscopic eight-legged animals are known to be capable of overcoming states of cryptobiosis – the suspension of metabolic processes – and tolerating periods of dehydration of up to ten years, as well as resisting extreme temperatures and surviving in vacuum or pressure conditions abnormal and ionizing radiation.
Despite this, the results of the experiment suggested that it is unlikely that tardigrades aboard a meteor would come out alive from an impact with another bodyas these collisions occur at speeds well above one kilometer per second.