Astronomers have found that bacteria can survive outside Earth in Space. The discovery of colonies of live bacteria outside the International Space Station indicates that clumps of microbes could survive the conditions of outer space and colonize other worlds.
Life is not compatible with the conditions of outer space. Temperatures close to absolute zero, vacuum and nothing to stop radiation. Any one of these factors alone is enough to tear cell membranes, destroy DNA, and kill any form of life, micro or macroscopic.
That’s why it was so surprising to find bacteria of the genus Deinococcus clumped together in colonies that had survived outside the International Space Station (ISS) for three years, according to Frontiers of Microbiology .
By joining together, the bacteria can withstand the extreme conditions of space protected by the outer layers of the cluster. The microbes nestled in the heart of these bacteria balls survive thanks to their dead companions in the outer layers. These microbial “arks” could drift between planets, spreading life throughout the universe, a concept known as panspermia .
Previous research has already found that microbes can survive in space when embedded in artificial meteorites, but this is the first study to show that microbes can survive that long without protection.
This also rekindles the debate about the necessary precautions for travel to other planets, specifically Mars, which could be contaminated with bacteria from the earth carried by space probes, or in the future the astronauts themselves, which would ruin any investigation into the possibility. of indigenous life on the planet.
For this experiment, in 2015 researchers from the Tokyo Institute of Space and Astronautical Sciences sent dried granules of Deinococcus, a bacterium known to be resistant to radiation, into space and placed outside the space station. The samples were returned to the ground, and the bacteria were fed back, hoping they would come back to life.
The bacteria in the 100-micron-thick granules did not survive, the radiation had fried their DNA. The outer layers of bacteria in the 500- and 1,000-micron-thick granules were also dead, but these dead bacteria protected those inside. About 4% of the microbes inside these granules survived.
With these data, the Japanese researchers estimate that a 1,000-micrometer (one millimeter) granule would allow bacteria to survive eight years floating in space, “long enough to potentially reach Mars,” they add.
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