Bear cub Turtle Milnesium tardigradum. Credit. Schokraie et al. (2012). PLoS ONE. CC BY 2.5.
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Legendary turtles are extremely durable. People usually think that they will survive everything. As a result, wild hypotheses have emerged around tortoises, according to which tortoises could spread through space if they “stop” suitable meteorites. Our experience with the solar system, which is obviously not full of turtles or similar super-resistant organisms, suggests that this is nonsense.
At the same time, however, it would be a great pity not to thoroughly test such a hypothesis. Who would resist the temptation to fire turtles with a high-velocity cannon? Certainly not the team of the British University of Kent. They tested the turtles’ resilience by firing them frozen into the sand at high speeds with a high-velocity gas cannon and watching the turtles survive. In this way, they mimicked the impacts of meteorites that would be necessary for the panspermic spread of turtles among the worlds.
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Logo. Credit: University of Kent.
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The list of turtle superpowers is impressive. They will survive heat, frost, dryness, intense radiation, crushing pressure and launch into space and many other miseries. They can enter a state of cryptobiosis, in which all metabolic processes in the body cease and turtles become incredibly resistant. Alejandra Traspas and Mark Burchell explored how turtles would cope with pansperm, the spontaneous spread of life between worlds, if such a thing exists at all.
The researchers first frozen the solution with the turtles for 48 hours. This forced them to enter a state of cryptobiosis and activate superpowers. Then they loaded the ice with the turtles into a gas cannon and fired them into the sand. They measured the speed of the shot and the pressure that such an impact would cause. After each shot, they carefully examined the condition of the turtles and any damage they had suffered.
Turtle in an optical microscope. Credit: Bob Blaylock / Wikimedia Commons. CC BY-SA 4.0
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The results of the experiments showed that the impact speed limit at which turtles can still survive is about 3,240 kilometers per hour (900 m / s). When impacted at such a speed, the turtles are subjected to a force corresponding to a pressure of 1.14 GPa. 100 percent of the turtles used survived at 2,261 kilometers per hour (628 m/s)while at a speed of 2,970 kilometers per hour (825 m/s) about 60 percent of turtles survived. At the same time, it turned out that it is not easy for turtles. After firing with a high-velocity cannon, compared to turtles, which were only frozen but not fired with a cannon, they recovered about four times longer (36 hours vs 8-9 hours).
Experiments have revealed that turtles certainly do not survive “everything”. Obviously, even the harsher impacts of meteorites will not survive. However, slower and less extreme shocks of space debris can survive. For example, in meteorites hitting the moon’s surface, it could be as much as one-third. The resistance of the turtles to the impact on the surface of the Moon has already been tested by the Israelis, when the Beresit module, which had frozen turtles on board, crashed on the moon during landing. We just don’t know how the experiment actually turned out.
The authors of the study came to the optimistic conclusion that panspermia through meteorites transmitting life between worlds is possible under certain circumstances. At the same time, it can be seen that researchers are looking forward to continuing their research. They are interested, for example, in how viable the turtles are after they have been fired from a cannon, or whether the eggs of turtles will survive such a shot.
Literature
Astrobiology online 11. 5. 2021.
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