A bacterium, named
Deinococcus radiodurans, is renowned for its exceptional endurance. Also nicknamed "Conan the Bacterium," this microorganism has a thick envelope and a remarkable ability to repair its DNA, allowing it to withstand hostile environments similar to those of space.
To simulate the forces generated by an asteroid impact, scientists placed samples of this bacterium between steel plates. Using a gas gun, they fired a projectile at high speed, subjecting the microbes to pressures of up to 3 gigapascals. These values are well above those of the deepest ocean floors on Earth.
Artist's impression of an asteroid crashing into Earth.
© Freepik
The results reveal that the vast majority of the microbes survive pressures of 1.4 gigapascal, and 60% remain alive at 2.4 gigapascals. At higher levels, damage to cellular membranes is observed, but some bacteria maintain significant activity. This endurance surpassed the experimenters' expectations. The experimental setup even failed before all the bacteria were eliminated.
These observations support the theory of lithopanspermia, which proposes that life can travel between planets by clinging to rocky debris after impacts. This research indicates that some organisms could withstand interplanetary journeys, fueling debates about the emergence of life on our planet and elsewhere.
The bacterium Deinococcus radiodurans surviving simulated asteroid impact pressures.
Credit: Lisa Orye/Johns Hopkins University The theory of lithopanspermia
Lithopanspermia proposes that life can spread between planets via rock fragments ejected by cosmic impacts. This idea stems from the observation that meteorites can transport organic materials from one world to another. While unproven, it offers a possible explanation for the appearance of life on Earth, if microbes traveled from Mars or other celestial bodies.
Previous studies have shown that some bacteria can survive in space, enduring vacuum and radiation. The new research on
Deinococcus radiodurans adds pressure resistance as a determining factor. This strengthens the hypothesis that asteroid impacts could serve as interplanetary vehicles for microbial life.
The implications are vast: if lithopanspermia is valid, life could be widespread in the Universe. Scientists are now exploring other microbes and conditions to test this theory more comprehensively.