Scientists identify types of planets we should search for intelligent alien life

By James Gamble via SWNS

Planets with high levels of oxygen should be prioritized in the search for intelligent alien civilizations, according to a new study.

The findings suggest that space scientists should focus on planets where oxygen is present - as they are more likely to be inhabited by advanced extra-terrestrial intelligence.

Because oxygen is crucial to developing fire - the hallmark of technological civilization - top astrophysicists believe the presence of oxygen on distant planets could offer major clues in discovering intelligent aliens with societies that rival our own.

Whilst astrobiologists have long recognized the importance of oxygen for life as we know it, scientists now believe oxygen could also be a key to unlocking advanced technology on a planetary scale.

Study lead author Dr. Adam Frank, a Professor of physics and astronomy at the University of Rochester in New York, 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?”

Co-author Amedeo Balbi, Associate Professor of Astronomy and Astrophysics at the University of Roma in Italy, 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.”

The new study, published in the journal Nature Astronomy and part-funded by NASA, theorizes that, beyond its necessities for respiration and metabolism in multicellular organisms, oxygen is also crucial to developing the hallmarks of technological civilization.

The authors delve into the concept of 'technospheres'; expansive realms of advanced technology that emit telltale signs - or technosignatures - of extraterrestrial intelligence.

Here on Earth, the development of technology has required easy access to open-air combustion - the process at the heart of fire - in which something is burned by combining a fuel and an oxidant, which is usually oxygen.

Whether for cooking, forging metals for structures, crafting materials for homes or harnessing energy through burning fuels, combustion has been the driving force behind industrial societies on our planet.

Looking back throughout history, the researchers noticed that the controlled use of fire and the subsequent advances of humankind were only possible when oxygen levels in the atmosphere either reached or exceeded 18 percent.

By their theory, this means that only planets with significant oxygen concentrations will be capable of developing advanced technospheres and leaving detectable technosignatures.

However, the levels of oxygen required for biologically sustaining complex life and intelligence are not as high as the levels required for technology.

So, whilst a species might be able to emerge in a world without oxygen, the researchers believe it would not be able to become a technological species.

To better describe this theory, the authors of the study coined the term 'oxygen bottleneck' to describe the threshold between worlds capable of fostering technologically advanced civilizations and those that fall short.

"You might be able to get biology - you might even be able to get intelligent creatures - in a world that doesn’t have oxygen,” Dr. Frank explained.

"But, without a ready source of fire, you’re never going to develop higher technology because higher technology requires fuel and melting.

“The presence of high degrees of oxygen in the atmosphere is like a bottleneck you have to get through in order 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."

The space experts say their research, which addresses previously unexplored facets in the cosmic pursuit of intelligent life, highlights the need to prioritize planets with high oxygen levels in the search for extraterrestrial technosignatures.

“Targeting planets with high oxygen levels should be prioritized because the presence or absence of high oxygen levels in exoplanet atmospheres could be a major clue in finding potential technosignatures,” Dr. Frank concludes.

“The implications of discovering intelligent, technological life on another planet would be huge,” Balbi added.

“Therefore, we need to be extremely cautious in interpreting possible detections.

"Our study suggests that we should be skeptical of potential technosignatures from a planet with insufficient atmospheric oxygen."