A bacterium known for surviving extreme radiation has now demonstrated it can also endure the pressures generated when an asteroid slams into a planet and blasts surface material into space. The finding, published in PNAS Nexus, adds concrete experimental weight to the hypothesis that microbial life can travel between planets carried inside impact debris.
Researchers Lily Zhao, K. T. Ramesh, and colleagues subjected Deinococcus radiodurans to pressures of up to 3 GPa, equivalent to 30,000 times normal atmospheric pressure. To achieve this, they sandwiched bacterial cells between two steel plates and struck the assembly with a third plate, replicating the shock conditions a microbe would experience during a large asteroid impact on Mars.
What the Bacteria Endured
The results were clear. At pressures around 2.4 GPa, the bacteria began showing ruptured membranes, a sign of serious physical damage. Yet even at that level, the structural properties of the cell envelope allowed 60% of the microbes to survive. The bacterium’s genetic response was equally telling: transcription profiles showed the cells immediately prioritized repairing cellular damage after the pressure event, rather than normal metabolic functions.
That active repair response matters. It suggests the organism is not simply passively resistant to mechanical stress but mounts a coordinated biological recovery. The ability to read out gene expression at varying pressures gave researchers a direct window into how the bacteria processed the trauma at a molecular level.
Why Mars Is the Context
Mars is no stranger to large impacts. Crater records on both the Moon and Mars document how frequently bodies in the solar system absorb incoming material. When an asteroid hits with enough force, surface rock and any material embedded within it can be accelerated past escape velocity and flung into space. Some of that debris eventually reaches other planets.
This process, known as lithopanspermia, has long been theorized as a potential mechanism for spreading life across the solar system. The central question has always been whether any organism could survive the violence of the launch itself. This experiment addresses that directly.
Deinococcus radiodurans was already a well-established candidate for interplanetary survival. Previous research demonstrated it can withstand radiation doses far beyond what would kill a human, as well as extreme desiccation. The new data on pressure tolerance adds a third column to that resilience profile.
Implications for Planetary Science
The researchers concluded that microorganisms can survive more extreme conditions than previously thought, including the launch phase of an impact-driven ejection event. That conclusion has bearing on how scientists interpret the history of life on Earth, and whether Mars, which may have harbored liquid water early in its history, could have shared biological material with other planets in either direction.
The study does not confirm that life has traveled between planets. It establishes that at least one known organism possesses the physical durability to survive a critical part of that journey. The other variables, including surviving the transit through space and atmospheric entry at the destination, remain open questions that future research will need to address.
Photo by Wolfgang Hasselmann on Unsplash
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