A colony of bacteria was found on samples from the Ryugu asteroid, but not alien at all

Scientists from Imperial College London discovered a colony of microorganisms on a sample from the Ryugu asteroid they received for study. True, they did not come from space. Within a week from the moment the sample was contaminated with terrestrial microbes, their colony grew from 14 to 147 units. The “invaders” liked the new habitat. Earth’s microbes turned out to be able to live and develop on an alien substrate, which must be feared when sending missions to other planets.

On the left is the Ryugu asteroid, and on the right are samples from it and terrestrial microbes discovered there. Image source: Collage space.com

The Japanese mission Hayabusa 2 launched in December 2014. The JAXA probe approached the asteroid Ryugu in June 2018. The spacecraft then spent a year studying the asteroid, which is about 900 meters in diameter, before descending on its surface and taking samples. Rock samples from the asteroid were returned to Earth on December 6, 2020. After sorting the material, it was sent to many scientific teams around the world, including a group of scientists from Imperial College London, who, in fact, discovered the fact that extraterrestrial samples were contaminated with terrestrial bacteria.

Scientists believe that the sample came into contact with the Earth’s atmosphere, which led to it being exposed to a microorganism. The researchers got an already dead colony. A detailed analysis showed that the primary infection was caused by 14 microorganisms, which then formed a colony and multiplied by an order of magnitude. To find out the exact name of the “invaders” it is necessary to conduct a DNA test, but this is not within the remit of this group. The knowledge of its participants was enough to attribute the discovered microorganisms to the genus Bacillus. This is enough for a clear understanding that terrestrial microorganisms are aggressive enough to survive in an environment completely alien to them.

The discovery reminds us that work with samples from space must be carried out under ultrasterile conditions, otherwise it would be an exaggeration to talk about the reliability of the detection of organic materials there. It is also necessary to take care of the sterility of spacecraft that will land on the surface of other planets or celestial bodies. Earth’s microorganisms have proven their ability to survive and adapt to life in harsh conditions and in unusual environments. Therefore, there is no need to help them spread throughout the solar system. They can handle this without us.