When humans return to the moon, they may find other living creatures waiting for them. The cargo on an Israeli private lunar lander, Beresheet, that crashed onto the moon's surface in April included a box full of a few thousand dehydrated tardigrades. The microscopic creatures, considered one of the toughest animals on the planet, are the only known living things thought to be able to survive in outer space, per Newsweek. And they may be doing that now. "Our payload may be the only surviving thing from that mission," the founder of a US-based organization that put a lunar library on Beresheet, including the tardigrades, told Wired. They could live there for years. "Tardigrades can survive pressures that are comparable to those created when asteroids strike Earth," an expert tells the Guardian, "so a small crash like this is nothing to them."
"Hardy" doesn't do the creatures, also called waterbears, justice. They can handle temperatures up to 304 degrees Fahrenheit. One survived being frozen for 30 years. That's because they can expel all of the water in their cells and continue living in a dormant "tun" state, with their metabolic processes switched off, until rehydrated. Dehydrated, inactive tardigrades have been rehydrated and revived up to a decade later, possibly even longer. Still, they won't be able to multiply on the lunar surface. "They cannot colonize the moon because there is no atmosphere and no liquid water,” the expert says. "But it could be possible to bring them back to Earth and then add the water. They should resurrect." (Tardigrades will likely survive to see the sun die.)