The boundary of the conditions under which life is possible has shifted a little further again. Researchers at Johns Hopkins University conducted a series of laboratory experiments with the bacterium Deinococcus radiodurans — one of the most resilient organisms on Earth. It managed to survive pressures comparable to those produced when an asteroid strikes a planet.
Deinococcus radiodurans has long been known as a “superbug.” It can withstand intense radiation, severe dehydration, cold and acidic conditions. The microorganism was exposed to brief pressure pulses of up to about 30,000 atmospheres. For comparison, pressure at sea level is about one atmosphere.
The bacteria remained viable even after a series of powerful shock pulses. At the same time, the organism did not just survive, but recovered. The analysis showed that some cells successfully repair damage after extreme stress.
These results add further weight to the panspermia hypothesis — the idea that life can spread between planets together with meteorite fragments. The work also has practical significance. If such resilient bacteria are capable of enduring cosmic disasters, an important question arises for future space missions: how to prevent Earth life from accidentally “contaminating” other planets.
Each new experiment with extremophiles shows that life is much more inventive than we are used to thinking. It can survive where, it would seem, there should be nothing alive at all.
