Air Supply: Coined by astrophysicists Adam Frank and Amedeo Balbi, the “oxygen bottleneck” describes the critical threshold that separates worlds capable of fostering technological civilizations from those that are not. “Without a ready-made fire source, you will never succeed in developing higher technology,” says Frank. Credit: Illustration by the University of Rochester / Michael Osadciw
In their quest to understand the potential for life beyond Earth, researchers are expanding their research to encompass not only biological markers, but also technological markers. While astrobiologists have long recognized the importance of oxygen to life as we know it, oxygen could also be key to the development of advanced technologies on a planetary scale.
In a new perspective published in Natural astronomyAdam Frank, Helen F. and Fred H. Gowen Professor of Physics and Astronomy at the University of Rochester and author of The Little Book of Aliens (Harper, 2023), and Amedeo Balbi, associate professor of astronomy and astrophysics at the University of Rome Tor Vergata, Italy, highlights the links between atmospheric oxygen and the potential rise of advanced technologies on distant planets.
“We are ready to find signatures of life on alien worlds,” says Frank. “But how do conditions on a planet tell us about the possibilities for intelligent, technology-producing life?”
“In our paper, we explore whether an atmospheric composition would be compatible with the presence of advanced technology,” explains Balbi. “We found that the atmospheric requirements could be very stringent.”
Lighting the cosmic technospheres
Frank and Balbi postulate that beyond its necessity for respiration and metabolism of multicellular organisms, oxygen is essential for the development of fire and that fire is a characteristic of a technological civilization. They delve deeper into the concept of “technospheres,” vast areas of advanced technology that emit telltale signs – called “technosignatures” – of extraterrestrial intelligence.
On Earth, the development of technology required ready access to open combustion – the process at the heart of fire, in which something is burned by combining a fuel and an oxidizer, usually oxygen. Whether cooking, forging metals for structures, making materials for homes, or harnessing energy through burning fuels, combustion has been the lifeblood of industrial societies.
Going back to Earth’s history, researchers found that the controlled use of fire and subsequent metallurgical advances were only possible when atmospheric oxygen levels reached or exceeded 18 percent. This means that only planets with significant concentrations of oxygen will be able to develop advanced technospheres, and therefore leave detectable technosignatures.
The oxygen bottleneck
The oxygen levels needed to biologically sustain complex life and intelligence are not as high as the levels needed for technology. So, even if a species can emerge in a world without oxygen, it will not be able to become a technological species, according to the researchers.
“You might be able to get biology – you might even be able to get intelligent creatures – in a world that has no oxygen,” Frank says, “but without a ready source of fire on the job, you will never be able to develop to a higher level of technology because higher technology requires fuel and smelting.
Enter the “oxygen bottleneck,” a term coined by researchers to describe the critical threshold that separates worlds capable of fostering technological civilizations from those that are not. In other words, oxygen levels are a bottleneck that hinders the emergence of advanced technologies.
“The presence of high levels of oxygen in the atmosphere is like a bottleneck that you have to get through to have a technological species,” Frank explains. “Everything else can work out, but if there is no oxygen in the atmosphere, there will be no technological species.”
Targeting extraterrestrial hotspots
The research, which addresses a previously unexplored facet of the cosmic quest for intelligent life, highlights the need to prioritize planets with high oxygen levels when searching for extraterrestrial technosignatures.
“Targeting planets with high oxygen levels should be a priority, because the presence or absence of high oxygen levels in the atmosphere of exoplanets could be a major clue to finding potential technosignatures,” says Frank.
“The implications of discovering intelligent technological life on another planet would be enormous,” adds Balbi. “Therefore, we must be extremely careful in interpreting possible detections. Our study suggests that we should be skeptical of potential technosignatures coming from a planet with a lack of atmospheric oxygen.”
More information:
Amedeo Balbi et al, The oxygen bottleneck for the technospheres, Natural astronomy (2023). DOI: 10.1038/s41550-023-02112-8
Provided by the University of Rochester
Quote: Astrophysicists explore links between atmospheric oxygen and detection of extraterrestrial technologies on distant planets (January 2, 2024) retrieved January 3, 2024 from
This document is subject to copyright. Except for fair use for private study or research purposes, no part may be reproduced without written permission. The content is provided for information only.
