Biologists at Tokyo University of Pharmacy and Life Sciences have shown that large colonies of certain bacteria can survive without any protection in space for several years. This is reported in the journal Frontiers in Microbiology.
As part of the Tanpopo mission to find opportunities for the spread of life between planets, scientists from 2015 to 2018 conducted a number of biological experiments on the International Space Station. In particular, they placed colonies of bacteria Deinococcus (Deinococcus) in the open research module of the ISS Kibo. The task of scientists was to find out whether these microorganisms, resistant to radiation and lack of oxygen, could survive in the harsh space conditions without any protection.
According to the theory of panspermia, life can move from one planet to another, including in natural ways, for example, using asteroids. As a result, a theory arose according to which life on Earth did not appear independently, but was brought in from the outside. It is assumed that living microorganisms are able to move between planets under the protection of solid celestial bodies. Japanese researchers went further and found that bacterial colonies are able to survive in space on their own.
- Astronaut Kimiya Yui before installing the external research module
- © JAXA / NASA
“The origin of life on Earth is the greatest mystery for humanity. Scientists may have completely different points of view on this matter. According to some, life is an extremely rare phenomenon, and in the Universe it arose only once. Others, on the other hand, are convinced that life can appear on any suitable planet. If panspermia is possible, then life is much more frequent than previously thought, ”said Akihiko Yamagishi, professor at the Tokyo University of Pharmacy and Life Sciences, chief researcher of the Tanpopo space mission.
In the course of other research by Dr. Yamagishi and his team, it turned out that live deinococci are found even at an altitude of 12 km above the Earth. Experiments on the ISS have proved that in large colonies these microorganisms are resistant to vacuum conditions, temperature changes and solar radiation.
- International space station
- © JAXA / NASA
Various samples with deinococci were carried out on the outer panels of the ISS for one to three years. Even after three years in space, large colonies of bacteria have partially survived. It turned out that the dying surface layer of bacteria served as protection for the core of the colony, where life still glimmered.
With the help of computer modeling, it was possible to find out that bacterial colonies with a diameter of more than 0.5 mm could live on the panels of the ISS from 15 to 45 years. And colonies with a diameter of at least 1 mm could survive for eight years already in outer space, the researchers say. They believe their discovery has brought the proof of the panspermia theory one step closer.
“Our results suggest that, due to its resistance to radiation, Deinococcus is able to survive the journey from Earth to Mars and back,” concluded Dr. Yamagishi.
However, scientists have yet to find out whether such bacteria are capable of leaving their home planet alive and entering open space, as well as "landing" on other planets, and under what conditions.