Scientists Fired Tardigrades Out of a Gun to See if They Can Survive Space Impacts
We can now add "being fired out of a gun at high speeds" to the growing list of weird things tardigrades can survive.
How do we know? Scientists actually did it - and, believe it or not, it's for a good cause. They wanted to know if tardigrade-like organisms could survive certain conditions in space, in order to place constraints on where and how we might be able to find extraterrestrial life in the Solar System - and how we might avoid contaminating it. ...
How violent an impact can tardigrades survive? The answer would have implications for astrobiology, including the panspermia model, which proposes life can be distributed throughout the cosmos via asteroids and comets that crash into planets.
It can also tell us how likely tardigrades are to survive in places like the Moon or the Martian moon Phobos, which could have been impacted by ejecta from Earth and Mars respectively, potentially carrying microscopic life. ...
Finally, it can help us gauge the survival rate of tardigrade-like organisms in the saltwater plumes ejected from icy ocean worlds like Europa and Enceladus. ...
The researchers loaded two or three individuals of Hypsibius dujardini, a species of freshwater tardigrade, each into a number of nylon sabots, which were frozen to induce the creatures' hibernation state, known as tun.
These sabots were then loaded into the gun, and fired at sand targets in a vacuum chamber at a range of velocities from 0.556 to 1.00 kilometers per second.
The sand target was then poured into a water column to isolate the tardigrades, which were separated and observed to determine how long it took them to revive from the tun state. As a control, 20 tardigrades were frozen and not shot out of a gun.
All of the control tardigrades recovered after about 8 or 9 hours. The impacted tardigrades survived up to and including an impact velocity of 825 meters per second; but they took longer to recover, suggesting internal damage. The next highest velocity, 901 meters per second, resulted in tardigrade jam. (That's still higher than many handgun muzzle velocities.) ...