Scientists at Johns Hopkins University have carried out an unusual experiment aimed at a question that has fascinated researchers for decades: Could microscopic life survive the violent forces needed to travel between planets?

The study does not suggest that humans literally came from Mars. Still, the results hint that some microbes might endure far harsher conditions than scientists once believed.

Testing a super-tough microbe
According to the Daily Star, researchers centred their work on Deinococcus radiodurans, a bacterium famous among microbiologists for its resilience. It has long attracted interest from astrobiologists because it can withstand radiation, extreme dryness and other environmental stress that would kill most organisms.

To test its limits, the team subjected the microbe to sudden bursts of intense pressure generated by high-speed impacts in laboratory equipment designed to mimic the shock of a planetary collision. The scenario researchers wanted to recreate is the moment when an asteroid strikes a planet and blasts rock fragments into space.

The outcome caught the research team off guard.

“We expected it to be dead at that first pressure,” Dr Lily Zhao, a NASA fellow at Johns Hopkins who led the work, told The Telegraph.

Instead, the bacterium kept surviving as the pressure increased. “We started shooting it faster and faster. We kept trying to kill it, but it was really hard to kill.”

A stubborn microbe may sound like a small detail. In astrobiology, it matters a lot.

If organisms can survive the initial shock of being blasted off a planet, one of the biggest obstacles to interplanetary transfer becomes less severe. Scientists refer to this possibility as lithopanspermia, the idea that life could spread naturally between worlds through rocks ejected by asteroid impacts.

Some parts of that scenario are already known to happen. Researchers have identified dozens of meteorites found on Earth that originated from Mars, confirming that fragments of the Red Planet can eventually reach our world.

Read More: Could life have hitchhiked to Earth on a rock from Mars?