Scientists at Johns Hopkins University have shown that the Deinococcus radiodurans bacterium can withstand the enormous pressures of an asteroid impact, supporting the idea that life can travel between planets.
The discovery raises new questions about the origins of life on Earth and calls for a review of space pollution policies.
A new study from Johns Hopkins University confirms that tiny life forms can survive flying into space after an asteroid impact, providing the strongest evidence yet for the “lithopanspermia” hypothesis.
Published in PNAS Nexus, study proves hardy bacteria can withstand the extreme pressures of planetary eruptions And the grueling journey through the vacuum of space could spread life between worlds like Mars and Earth.
Test bacteria: Deinococcus radiodurans
To test the limits of life, researchers led by Professor KT Ramesh and first author Lily Zhao focused on Deinococcus radiodurans. Also known as “Conan the Bacteria,” this microorganism is famous for its ability to withstand intense radiation, extreme cold, and complete dehydration. The researchers wanted to see if it could withstand the “unique biological stress” of being blown off the planet’s surface.
The experiment used a high-tech gas gun that fired projectiles at the bacteria at speeds of up to 300 miles per hour. The goal was to recreate the 1-3 gigapascal pressures typical of asteroid impacts on Mars.
By the way, this is more than 10 times the pressure found at the bottom of the Mariana Trench.
survive through adversity
The results surprised the researchers.
This bacteria is incredibly difficult to kill, with 100% survival at 1.4 gigapascals and 60% survival at 2.4 gigapascals. Although the high-pressure experiments eventually caused membrane rupture and internal damage, many cells remained viable. In fact, the steel equipment used to house the bacteria collapsed before the microbes did.
“We kept trying to kill it, but it was really difficult,” Zhao said. The study suggests that if life exists on Mars, it is likely to have similar self-healing capabilities, making it possible for Martian debris (many of which have already been found on Earth) to carry living “passengers.”
Impact on space missions
These findings areplanet protectionCurrent rules for space missions are designed to prevent life from Earth from contaminating other planets, and vice versa. But this study suggests that natural processes may already be moving life between celestial bodies.
The researchers highlighted the moon Phobos as a particular concern. Because it orbits so close to Mars, it is a likely place for ejected Martian debris to land at relatively low pressures. This means future missions to Phobos and other nearby moons may require stricter safety measures to account for the possibility of microbes “hitchhiking”.