From Live Science:
Toxitolerant organisms can withstand high levels of damaging agents. They can be found swimming around in benzene saturated water or in the core of a nuclear reactor. One species of bacteria, Deinococcus radiodurans, can withstand a 15,000 gray dose of radiation – 10 grays would kill a human and it takes over 1,000 grays to kill a cockroach. Extraterrestrial life forms would most likely need to possess similar tolerances to radiation, as the atmosphere on other planets, or lack thereof, filters out much less radiation than Earth’s. “If it works this way on Earth, it’s likely to happen elsewhere,” says Spear, the University of Colorado scientist. “When you look up at the stars, there is a lot of hydrogen in the universe.”
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