Gravitational Forces Don't Hinder Microbial Growth

Astrobiologists now believe that life may in fact be able to survive, or even thrive, in a much wider array of environments than previously thought. The conclusion was drawn from a study that shows microbes to be largely unaffected by the gravitational forces that act upon them.

In other words, it would appear that these microorganisms can develop and multiply even in environments were gravity is a lot stronger or a lot weaker than it is here on Earth.

As such, it stands to reason that – given the right conditions – lifeforms may develop on planets that are similar to Earth in most aspects, but differ in terms of the gravitational pull they subject objects on their surface to.

Scientists explain that microbes were found to survive in 400,000 times the normal gravitational pull of Earth – this is called hypergravity. The most important implication of this new study is that life may have been brought here from outer space.

The work makes the case for a theory holding that the seeds of life were brought here on comets and asteroids coming in from the solar system or beyond. With the new data, experts are now certain that early microbes or bacteria were able to survive the devastating impacts their carriers produced.

“The number and types of environments that we now think life can inhabit in the Universe has expanded because of our study,” explains expert Shigeru Deguchi, who is based at the Japan Agency of Marine-Earth Science and Technology, in Yokosuka.

The expert was also the lead author of the new study, which was published in the April 25 issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS), Space reports.

In the experiments, the Japanese team analyzed the behavior of E. coli bacteria, an organism commonly used for such investigations. Cultures were placed inside a centrifuge, and the device spun so fast that it simulated 7,500 times the normal gravitational force that Earth produces.

Regardless of these savage conditions, the E. coli cultures were able to survive, multiply and grow unimpeded. “The finding was a total surprise to us, and stimulated our curiosity very much,” Deguchi says of the results.

“So we repeated [the] same experiments at higher G, and eventually found that E. coli proliferates even at 400,000 G, which was the highest gravity we could achieve by our instrument,” he goes on to say.

E. coli and Paracoccus denitrificans were the two microorganisms that managed to endure up to 400,000 G. But, of the five organisms the team studied, all were able to survive until at least 20,000 G.

“If life does exist in other places in the universe, our study provides further evidence that it could spread within solar systems by the mechanism often discussed in panspermia hypotheses – i.e., impact-based transport of meteorites between bodies of the same solar system,” Deguchi concludes.