Tardigrades are one of nature’s most indestructible lifeforms. These microscopic animals can survive both freezing and boiling temperatures, pressures equivalent to those six miles under the ocean, and even the vacuum of outer space.
But for one pair of scientists, a lingering question remained: can tardigrades survive being shot out of a gun headlong into an impact target?
It’s a worthy hypothetical in any context, but there also happens to be a legitimate scientific reason to conduct such an experiment. For decades, scientists have speculated about the possibility that hardy organisms might be able to survive trips between planets by hitchhiking on meteorites. This theory of interplanetary cross-pollination, known as panspermia, has implications for understanding how life might have emerged on Earth and whether it is common elsewhere in the universe.
With this in mind, Alejandra Traspas and Mark Burchell, a PhD student and professor of space science at the University of Kent, respectively, sought to determine whether spacefaring tardigrades would be able to withstand the sudden impact of arrival at an alien world.
In a study published this month in the journal Astrobiology, the researchers point out that “there is no knowledge of how [tardigrades] survive impact shocks” and so “accordingly, we have fired tardigrades at high speed in a gun onto sand targets, subjecting them to impact shocks and evaluating their survival.”
“We had no real info, only guesswork,” Burchell said in an email. He noted that past studies of tardigrade-scale seeds break apart when they impact at speeds over 2,200 miles per hour, and at shock pressures of 1 gigapascal (GPa), which suggested that it “might be an interesting regime to test” actual tardigrades in the same conditions.Tech
“The results were however a surprise in that the tardigrades seemed to recover from impacts, right up to speeds which started to physically tear them into pieces,” Burchell added.