Oxygen is vital for the respiration and metabolism of multicellular organisms on Earth, and it might play a crucial role in developing a complex biosphere on other planets. Since life, mainly through photosynthesis, has been responsible for shaping our oxygen-rich atmosphere, oxygen has been considered a potential biosignature in the search for extraterrestrial life.
While astrobiologists have long recognized the importance of oxygen for life as we know it, oxygen could also be a key to unlocking advanced technology on a planetary scale.
In a new study, Rochester astrophysicist Adam Frank and Amedeo Balbi, an associate professor of astronomy and astrophysics at the University of Roma Tor Vergata, Italy, outline the links between atmospheric oxygen and the potential rise of advanced technology on distant planets.
Frank said, “We are ready to find signatures of life on alien worlds. But how do the conditions on a planet tell us about the possibilities for intelligent, technology-producing life?”
Balbi said, “In our paper, we explore whether any atmospheric composition would be compatible with the presence of advanced technology. We found that the atmospheric requirements may be quite stringent.”
Frank and Balbi suggest that oxygen, besides being essential for living organisms, is also crucial for fire, a necessary aspect of advanced civilizations. They introduce the idea of “technospheres,” areas with advanced technology emitting signals known as “technosignatures,” indicating possible extraterrestrial intelligence.
On Earth, technological progress needed access to open-air combustion, central to fire. Whether for cooking, building, crafting, or energy production, combustion has driven industrial societies.
Looking at Earth’s past, the scientists found that controlled fire use and metallurgical advancements were only possible when atmospheric oxygen levels were 18 percent or higher. This suggests that planets with substantial oxygen can develop advanced technospheres, leaving behind detectable technosignatures.
To sustain complex life and intelligence, a planet needs lower levels of oxygen compared to what’s necessary for technology. This means a species could evolve on a planet without much oxygen but wouldn’t be able to become technologically advanced.
This concept is termed the oxygen bottleneck. It refers to the critical threshold that distinguishes planets capable of nurturing technological civilizations from those that cannot. In other words, oxygen levels act as a bottleneck, limiting the emergence of advanced technology.
Frank said, “The presence of high degrees of oxygen in the atmosphere is like a bottleneck you must get through to have a technological species. You can have everything else work out, but if you don’t have oxygen in the atmosphere, you’re not going to have a technological species.”
Through this study, scientists explored previously unexplored facet in the cosmic pursuit of intelligent life. It also highlights the need to consider oxygen-enriched planets for the search of extraterrestrial technosignatures.
Journal Reference:
- Balbi, A., Frank, A. The oxygen bottleneck for technospheres. Nat Astron (2023). DOI: 10.1038/s41550-023-02112-8
