Some of Earth's commonplace microbes survived for 3 years in outer space in an experiment conducted by a team of researchers from Tokyo University of Pharmacy and Life Sciences and the Japan Aerospace Exploration Agency. The study's results, published Wednesday in a Swiss journal, showed that life might be able to travel in space surrounded by radiation and ultraviolet rays for extended lengths of time.
One of the hypotheses on the origins of life on Earth is that it was brought about by the arrival of foreign objects such as interstellar microbes.
From 2015 to 2018, five bacteria clusters were exposed to outer space at the International Space Station (ISS) and their ability to survive was verified by the research team. The bacteria clusters, originating from the earth's ground and other places, contained 2 million to 2.3 billion dormant bacteria.
After arriving back on Earth the samples were analyzed. Of the clusters containing more than a billion bacteria, a single digit percent survived and could grow in a culture fluid. The ultraviolet damage done to the surviving bacteria's DNA was minimal as it was protected by the surrounding bacteria, and damage done to the bacteria may have been repaired.
A research team from Russia and others had previously announced experimental results of microbial spores surviving in space if exposure to ultraviolet light was blocked. However, the latest experiment confirmed for the first time microbes surviving in an environment present with ultraviolet rays, according to research team member Akihiko Yamagishi, professor emeritus at Tokyo University of Pharmacy and Life Sciences.
"We obtained a piece of evidence that the hypothesis that the origin of life on Earth was brought from space is possible," Yamagishi said.
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