Our intuition that life is much more common in the universe than technology can mislead us. Re-evaluation can affect how resources are prioritized in one of science’s most important tasks.
The quest to find life beyond Earth has taken two broad paths – searching for signs of intelligent life such as radio signals, or searching for the effects of biological activity. Having failed on both counts so far, it’s hard to be specific as to which is more likely. A study published in The Astrophysical Journal Letters presents a somewhat illogical argument for technology over biology.
The argument for looking for biological signs is simple. Not all living worlds will produce civilizations whose technology we can detect, and it is likely that the vast majority will not. A star like Alpha Centauri could easily have life forms on orbiting planets, the possibility of something high-tech is remote. This idea is implicitly encoded in Drake’s famous equation, an attempt to calculate the number of technological civilizations in the galaxy.
Dr. from Penn State University. Jason Wright and his co-authors argue that this simple reasoning should be weighed against four factors that may collectively prevail.
The most obvious of these is ease of detection. If a radio signal is strong enough, we can detect it in the galaxy, whereas biomarkers are probably only detectable around nearby stars.
There’s also the fact that technological lifeforms can spread their wares far more widely than they would otherwise. As far as we know, only Earth supports life in our solar system, but human technology can be found on Mars and the Moon and orbiting Venus and Jupiter. It is possible that some will remain functional long after not only humanity but all life on Earth is gone.
The authors argue that the possibility that the technology may continue to reproduce (by design or accidentally) far beyond its original creators must also be considered.
Finally, while life depends on planets, or at least moons, technology can exist between worlds and even between star systems.
The authors note that those involved in the search for extraterrestrial intelligence are familiar with many of these arguments, but less so with other astrobiologists.
To weigh these arguments, the authors modified Drake’s original equation to produce two “Drake-like” versions that predict the number of technological or biological signatures to be found. As with the original version, each requires estimating the probability of various events, which often has little to do.
Will one in a hundred planets supporting life end up developing a technologically advanced civilization, or one in a million? No one knows but many people have ideas. Where spaceflight succeeds, does it lead, on average, to the colonization of a handful of planets or millions? The answer is equally vague. Depending on the numbers you choose, the authors note, biological signatures can be inferred much more than technological signatures, or vice versa.
“An objective and quantitative comparison of the true relative abundances of techno-signatures and bio-signatures is difficult because it depends on details of extraterrestrial life that we will not know for sure until we have a few examples to learn,” indicates the document. . was written.
On the other hand, where the technology is, we can probably be more confident that it will be easier to find signs of life, at least while it’s still working, rather than a massive wreckage. Technology signals are also less likely to be ambiguous.
When astronomers like Frank Drake first pondered the question, they had little choice. We can look for signs of biology on Mars and perhaps elsewhere in the solar system, but anywhere further will depend on radio signals. We couldn’t even detect the most distant planets, let alone examine their atmospheres for signs of gaseous life.
Today we know of thousands of exoplanets, some of which could potentially harbor life. Future telescopes, if they exist, might at least allow us to find evidence in closer samples. While JWST will transform other areas of astronomy, the authors believe we get what we pay for when it comes to bringing the Square Kilometer Array to life, with its vastly improved ability to detect radio signals.