Khaberni - A new study reveals the possibility of microorganisms surviving harsh space journeys, leading to a revival of questions about the transfer of life between planets.
A recent scientific study revealed striking results indicating that some microorganisms can survive extreme conditions, potentially enabling them to transfer between planets, thus reviving an old scientific hypothesis related to the origin and spread of life in the universe.
The idea that life could transfer from one world to another dates back to ancient Greek times, when the philosopher Anaxagoras proposed it. This hypothesis, known as «Panspermia», suggests that life or its seeds could transfer between planets. Although it is not fully accepted as a scientific theory, it has persisted over time and gained partial support thanks to recent discoveries indicating a broader spread of basic chemical building blocks for life in the universe.
In this context, recent research on extreme life forms demonstrated that some of these organisms could have survived being ejected from the surface of Mars due to an asteroid impact, where their ability not only to withstand the tremendous pressures resulting from the impact but also to survive the journey between planets, despite the associated risks, especially if trapped inside the resulting rocky debris.
The study titled «Survival of an extremophile from temporary pressures associated with ejection from Mars» was published in the journal PNAS Nexus, led by Lili Zhao, a graduate student in the Mechanical Engineering department at Johns Hopkins University.
The researchers noted that planetary collisions generate immense pressures over very brief periods, leading to extreme strain and high loading rates, creating significant questions about the resilience of microorganisms under such harsh conditions.
To address this question, the research team chose an extremophile known as Deinococcus radiodurans, notable for its exceptional ability to withstand harsh conditions and the subject of many studies concerning life in extreme environments.
This organism is one of the most radiation-resistant life forms known so far and can survive in extremely harsh conditions such as intense cold, dryness, vacuum, and even acidic environments, thereby described as a highly tolerant organism to tough environmental conditions.
During the laboratory experiments, the researchers exposed this organism to extremely high pressures for short periods, attempting to simulate the conditions of planetary collision, then measured the survival rates and studied the mechanisms of repairing the damage incurred, as well as analyzing its response at the molecular level.
Researcher Lili Zhao said: «We repeatedly tried to kill it, but it was incredibly difficult to do so.»
The surviving samples' ribonucleic acid (RNA) was extracted and analyzed, showing that increased pressure leads to a rise in biological stress levels. Yet, survival rates remained high in numerous trials.
The researchers also found that Deinococcus radiodurans demonstrated a high survival rate even after being exposed to pressures up to 3 gigapascals and with increased pressure, there were signs of rising biological stress, as detected through transcriptional analysis of the samples.
The results suggest that microorganisms could withstand much harsher conditions than previously thought, including conditions that lead to the formation of rocky debris that could transfer across planetary systems.
Co-researcher K. T. Ramesh, a specialist in studying material behavior under harsh conditions, noted that these results suggest the potential for life to survive after being ejected from one planet to another, thereby reconsidering our understanding of the origin of life and how it emerged on Earth.
The team studied the samples after the collision to assess any cellular damage, using Transmission Electron Microscopy (TEM), comparing unaffected samples to those subjected to pressures of 1.4 and 2.4 gigapascals, showing structural and morphological changes in cells at higher pressure levels.
However, the fundamental outcome was that Deinococcus radiodurans could withstand very high pressures, even if only for short periods, with relatively limited effects on its survival.
Zhao mentioned that the laboratory equipment itself reached its limits before the researchers could eliminate all organisms within the sample.
Estimates suggest that collisions on the surface of Mars could generate pressures of up to 5 gigapascals or more, depending on several factors. Nevertheless, the survival of this organism up to a level of 3 gigapascals is a significant indicator for researchers interested in the 'Panspermia' hypothesis.
Zhao added that the study's results suggest the potential for life to survive after major planetary collisions and ejection into space, leading to the possibility that life may have transferred between planets, even proposing the possibility that life on Earth might have originated on Mars.
These results are not only significant for the hypothesis of life transfer but also extend to planetary protection, as the ability of this organism to withstand extreme pressures suggests it could potentially survive unintended transfers from Earth to Mars via spacecraft.
In this regard, Ramesh cautioned about the need to exercise caution when selecting planets for missions.
In conclusion, the researchers emphasized that these findings provide important indicators for understanding the outer limits of living organisms' survival, alongside supporting concepts of planetary protection, advancing the design of space missions, and enhancing understanding of the potential for life to spread across different planetary systems.
