Earlier work has demonstrated that an extremophile bacterium species called Deinococcus radiodurans can survive the radiation, cold, and desiccation associated with interplanetary transport. New research shows that Deinococcus radiodurans has outstanding ability to survive the extreme transient pressures associated with impact-induced ejection from Mars. Thus, it is possible for such life to be transported between planets in the Solar System as a result of major asteroid impacts.
This is an artist’s impression of an asteroid. Image credit: Mark A. Garlick, Space-art.co.uk / University of Warwick / University of Cambridge.
Impact craters cover the surfaces of most bodies in the Solar System. The Moon and Mars are among the most cratered celestial bodies.
Scientists know asteroid strikes can launch material across space; and Martian meteorites have been found on Earth.
However, they have long wondered if life forms could also be launched from an asteroid impact.
Tucked inside ejected debris, they might land on another planet — a theory called the lithopanspermia hypothesis.
In the new research, Johns Hopkins University researcher Kaliat (K.T.) Ramesh and colleagues simulated the conditions under which a microbe might be hurled into space by the force of an impact.
They subjected Deinococcus radiodurans to pressures of up to 3 GPa (30,000 times atmospheric pressure) by putting the cells between two steel plates and then hitting that steel sandwich with a third plate.
They were able to detect biological stress in the bacteria by reading out which genes were expressed at varying pressures.
Samples exposed to 2.4 GPa began to show ruptured membranes, but the structure of the bacterium’s cell envelope help explain the survival of 60% of microbes.
Transcription profiles suggest that the bacteria prioritized the repair of cellular damage in the aftermath of the impact.
Deinococcus radiodurans. Image credit: USU / Michael Daly.
“We do not yet know if there is life on Mars, but if there is, it is likely to have similar abilities,” Professor Ramesh said.
“Life might actually survive being ejected from one planet and moving to another.”
“This is a really big deal that changes the way you think about the question of how life begins and how life began on Earth.”
“We have shown that it is possible for life to survive large-scale impact and ejection,” said Dr. Lily Zhao, also from Johns Hopkins University.
“What that means is that life can potentially move between planets. Maybe we’re Martians!”
The results were published this week in the journal PNAS Nexus.
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Lily Zhao et al. 2026. Extremophile survives the transient pressures associated with impact-induced ejection from Mars. PNAS Nexus 5 (3): pgag018; doi: 10.1093/pnasnexus/pgag018
