Did Earth life actually begin on Mars? Asteroid impacts could let microbes planet-hop, study suggests

A new study suggests some microbes may be tough enough to survive one of the most violent steps in any planet-hopping scenario: being blasted off a world by an asteroid impact. Researchers working with the famously resilient bacterium Deinococcus radiodurans found that nearly all of the microbes survived shock pressures of 1.4 gigapascals and about 60% survived 2.4 gigapascals, conditions meant to mimic the forces involved when rock is ejected from a planetary surface.

The study does not prove life started on Mars, but it does strengthen the case that microbes could survive the violence needed to move between worlds.

That is why the story has real weight. If microbes can survive launch shock better than expected, scientists may need to think differently about how life could spread through the solar system and how carefully missions should avoid cross-contamination. It is still a long way from proving a Martian origin for Earth life, but it makes the old question harder to dismiss.