Microbes may hitchhike across the solar system via asteroid debris

A recent study from Johns Hopkins University demonstrates that microbes can survive the extreme pressures generated by asteroid impacts that eject planetary debris into space, supporting the lithopanspermia hypothesis that life could travel between planets embedded in rock fragments. Researchers tested the bacterium Deinococcus radiodurans, known for its resilience to radiation and harsh conditions, by subjecting it to shock pressures of 1 to 3 gigapascals—far exceeding pressures found in Earth's deepest ocean trenches. The bacteria survived nearly all tests at 1.4 gigapascals and about 60% at 2.4 gigapascals, showing remarkable viability even under conditions simulating asteroid impacts on Mars. These findings suggest that microbial life could endure the violent forces of planetary ejection and potentially transfer between worlds, including from Mars to Earth. This has important implications for planetary protection policies, as it raises concerns about contamination risks when exploring other celestial bodies or returning samples to Earth. The study also highlights the possibility that Mars