Researchers led by Zhao et al. said that microbes can survive the extreme pressures of an asteroid impact and potential ejection into space [1].
This discovery provides physical evidence for the possibility of panspermia, the theory that life travels between worlds via space rocks. If microorganisms can survive the initial violent launch from a planet's surface, they could potentially seed other celestial bodies with biological material.
To test this hypothesis, the team conducted experiments in a laboratory setting using a projectile apparatus [1]. The researchers sandwiched microbes between metal plates to simulate the crushing forces and heat generated during a collision. They then fired a projectile at the plates at a speed close to 500 kilometers per hour [1].
The experiment specifically aimed to mimic the conditions of an asteroid striking Mars and the subsequent ejection of surface material [1, 2]. By observing the survival rates of the microbes after the impact, the team could determine if the shock of ejection is a definitive barrier to interplanetary travel.
The findings, reported in Science Magazine and discussed in ScienceNews, suggest that the physical trauma of an impact does not necessarily destroy all microbial life [1, 2]. This means that fragments of rock, shrapnel from the impact, could act as biological vessels, carrying dormant or active organisms across the vacuum of space.
While the simulation focused on the ejection phase, the researchers said that survival during the long journey through space and the eventual landing on another planet are separate challenges [1, 2]. However, proving that the first stage of this journey is survivable removes a major hurdle in the scientific understanding of how life might spread through the solar system.
“Microbes can survive the extreme pressures of an asteroid impact and potential ejection into space.”
This research validates a critical mechanical step in the panspermia hypothesis. By demonstrating that the kinetic energy of an impact, simulated at 500 kilometers per hour, is not always lethal to microbes, the study shifts the scientific focus toward the survivability of long-term radiation exposure during interstellar transit and the viability of recolonization upon arrival.
