Latecomers can survive by being shot by guns at up to 2,000 mph
The adorable microscopic, cocoa-like, and almost invulnerable water bears known as tardigrades have another wonderful superlative to add to their resume: live bullets.
According to a new study from the journal of Astrobiology, scientists loaded tardigrades into cans and shot them gas pistols at extreme speeds to see how they fared. This is how you get wild passages like this:
The animals used here were the tardigrade species Hypsibius dujardini, which have been handled according to the rules of ethics of invertebrates with the agreement of the departmental ethics officer. The tardigrades were fed with mineral water and foam (see Fig. 1a, 1b). They were fired from a two-stage light gas pistol (Burchell et al., 1999; Hibbert et al., 2017) on sand targets in a vacuum chamber. Before firing, two or three tardigrades were loaded into a rod filled with water in a nylon shoe (the number was measured in each case). The hoof was then frozen for 48 h so that the tardigrades were in a tun state during firing. The sabot was then placed in the pistol and fired at normal incidence in the sand. The entire hoof impacted the target with each shot. Impact velocities were measured in each shot to better than ± 1% using two laser light stations mounted transversely to the direction of flight and focused on photodiodes. The signals from the photodiodes, combined with their known separation (499mm), provided the speed.
It turned out that tardigrades could survive impact at up to 2,000 miles per hour, or the equivalent of 1.14 gigapascals (GPa). “On top of that, they’re making porridge,” one of the scientists involved said. Scientific magazine.
The retardigrades were previously known to survive inside volcanoes, in the vacuum of space, and in Antarctic underground lakes where the pressure is about six times that of the deepest part of the Earth’s oceans. They can even return to normal operation after being frozen for three decades.
But the impetus for that particular experience was a 2019 Israeli space mission where someone smuggled secret tardigrades on board … before crashing into the moon. The tardigrade pistol test was therefore designed to help determine whether these tardigrade could have survived their disastrous lunar grounding.
Spoiler alert, dear reader: these shipwrecked tardigrades are in mush.
Late survival limits in high velocity impacts – Implications for panspermia and the collection of samples from plumes emitted by ice worlds [Alejandra Traspas and Mark J. Burchell / Astrobiology]
Resistant water bears survive bullet holes – to a point [Jonathan O’Callaghan / Science]
Image: Eden, Janine and Jim / Flickr (CC-BY-SA 2.0)