Of all the things we hope will happen someday but haven’t yet, finding intelligent life in space may be one of the most eagerly awaited by humanity. If it happens, it will open an extensive range of possibilities, which we won’t describe here. However, we still have no news of extraterrestrial beings. In this regard, NASA has just published a study that features a simple and feasible explanation for our inability to find “signals.”
The study. NASA's new study, published in The Astrophysical Journal, builds off the idea that other advanced civilizations exist. Not detecting them is difficult because “their energy requirements may be relatively modest. If their culture, technology, and population size do not need vast amounts of power, they would not be required to build enormous stellar-energy harvesting structures that could be detected by current or proposed telescopes,” the agency states.
In other words, and before we get into the paper and its implications, the study and the space agency say that if we haven’t seen “signals,” it’s because some extraterrestrial beings may not need to do all that we believe is necessary to advance life.
Remembering the Fermi paradox. More than half a century ago, physicist Enrico Fermi asked the big question: If we have so many planets and star systems, why haven’t we found signs of life? His thinking has motivated hundreds of scientists and philosophers to develop theories and carry out research. The one now offered by NASA is just another, but has a lot of common sense.
Simple space people. The researchers explored whether a next-generation space telescope could detect possible solar panels on a nearby exoplanet. The team concluded that if such intelligent life exists and gets its energy from solar power, it probably doesn’t need the power we need to detect it.
As Ravi Kopparapu, a researcher at NASA’s Goddard Space Flight Center and lead author of the study, explained, “The implication is that civilizations may not feel compelled to expand all over the galaxy because they may achieve sustainable population and energy-usage levels even if they choose a very high standard of living. They may expand within their own stellar system, or even within nearby star systems, but galaxy-spanning civilizations may not exist.”
A Habitable Worlds Observatory illustration.
Why silicon solar panels? The researchers started with the idea of a civilization that used the Sun as we do on our planet. Specifically, they wanted to see if they could detect silicon-based solar panels on an Earth-like exoplanet. They chose silicon-based panels because this element is more abundant than others used for solar energy and is cheaper to extract and use in manufacturing (at least here on Earth).
Then, they postulated the detection by our most sophisticated telescope, which will be ready in 2029. That is, they imagined observing Milky Way exoplanets with the Habitable Worlds Observatory, the flagship project of NASA’s Large Observatory Program. They modeled an Earth-like planet with various levels of silicon solar panel coverage and tested whether the telescope could detect these technology signals from 30 light-years away.
The results. The researchers found that if 23% of the land on this exoplanet had solar panels, it would take at least several hundred hours to detect these types of technology signals. They explain that only 9% of Earth’s land area is needed to support 30 billion people with a high standard of living. Covering nearly a quarter of a planet’s land with solar panels is an extreme scenario and, at least here, unnecessary when it comes to energy requirements.
The bottom line. As Vincent Kofman, study co-author and NASA researcher, said, “Large-scale stellar-energy harvesting structures may especially be obsolete when considering technological advances. Surely a society that can place enormous structures in space would be able to access nuclear fusion or other space-efficient methods of generating power.”
The paper assumes that this theoretical extraterrestrial civilization would use the solar energy of its host star as well as other energy sources, including those we don’t yet understand.
Another alternative. But perhaps, as the SETI Institute states about the ubiquitous Fermi paradox, we should consider another possibility. If we've seen no signs of extraterrestrial life so far, it may simply be a matter of quantity.
Space is so big, and we've been observing it for such a small amount of time that we’re still clueless: “The Fermi Paradox is a very large extrapolation from a very local observation. You might just as well look out your window and conclude that bears, as a species, couldn’t possibly exist because you don’t see any,” the SETI Institute concludes.
This article was written by Miguel Jorge and originally published in Spanish on Xataka.
Images | NASA
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