Space & Astronomy

Microbial life discovered in asteroid samples... but there's a catch

By T.K. Randall
November 26, 2024 ·  3 comments

There's life in these samples... but is it from space ? Image Credit: JAXA The samples, which were collected from the asteroid directly by Japan's Hayabusa-2 probe and returned to Earth back in 2020, have been the subject of intense scientific analysis ever since.

Last year, it was found that the material, which has turned out to be the most primitive ever studied in a laboratory, contains uracil - one of the four nucleobases of ribonucleic acid (or RNA) which is one of the building blocks of life on Earth.

But it was when samples sent to Imperial College London were studied more recently that a discovery was made that had the potential to prove once and for all that we are not alone in the universe.

Matthew Genge and colleagues had been studying the samples with a scanning electron microscope (SEM) when they saw, clear as day, the telltale signs of filament-shaped bacteria.

The researchers were so shocked that they were "falling off their chairs", Genge recalled."It was an exciting moment, but also in the back of my mind I knew from previous studies how easy it is for bacteria to colonize rocks," he said.

Sure enough, after conducting a thorough analysis, the researchers were able to determine that the bacteria - far from being evidence of alien life - was actually Earth-based bacteria that had managed to contaminate the asteroid samples.

"When we're preparing meteorite samples, for example, we usually don't see this colonization occurring, and that's because the chances are really low," said Genge.

"In this case, a single bacterium fell on that sample and started to grow."

On the positive side, the incident demonstrates how important it is to avoid contamination and to avoid jumping to conclusions too quickly should something like this be detected in a sample.

"Our discovery really shows that you have to be so incredibly careful about that interpretation, because samples are so easy to contaminate with terrestrial bacteria," said Genge.

Source: New Scientist | Comments (3)

Tags: Ryugu, Asteroid