Monday, May 24, 2021

"Good Night, Moon"

Waxing gibbous

12.0 days old

91.9 percent full

Poor little tardigrades are so mistreated. I think it is because they are ugly. No one cares about a tardigrade.

May 18, 2021
By Jonathan O'Callaghan

...Traspas (click here) and her supervisor, Mark Burchell, a planetary scientist at the University of Kent, wanted to find out whether tardigrades could survive such an impact—and they wanted to conduct their experiment ethically. So after feeding about 20 tardigrades moss and mineral water, they put them into hibernation, a so-called “tun” state in which their metabolism decreases to 0.1% of their normal activity, by freezing them for 48 hours.

They then placed two to four at a time in a hollow nylon bullet and fired them at increasing speeds using a two-stage light gas gun, a tool in physics experiments that can achieve muzzle velocities far higher than any conventional gun. When shooting the bullets into a sand target several meters away, the researchers found the creatures could survive impacts up to about 900 meters per second (or about 3000 kilometers per hour), and momentary shock pressures up to a limit of 1.14 gigapascals (GPa), they report this month in Astrobiology. “Above [those speeds], they just mush,” Traspas says.

The results suggest the tardigrades on Beresheet were unlikely to survive. Although the lander is thought to have crashed at a few hundred meters per second, the shock pressure its metal frame generated hitting the surface would have been “well above” 1.14 GPa, Traspas says. “We can confirm they didn’t survive.”...