Could It Be: Possible Signs of Extraterrestrial Intelligence?


We need to learn how to talk about possible signs of extraterrestrial intelligence.
Comet Swarm
This artist’s concept shows a swarm of comets passing before a star.
NASA / JPL-Caltech
In my most recent column, I discussed the lack of evidence for technically advanced extraterrestrials. Curiously enough, in the time between writing that and its publication, some possible evidence materialized.
I’m sure you’ve heard plenty about the star KIC 8462852. The Kepler spacecraft found that its light is quivering in a complex way, like a lantern harassed by a large moth. It doesn’t match anything predicted or observed around any other star. Something huge — perhaps half the star’s diameter — is in orbit there or passing in its vicinity, at times blocking up to 20 percent of the starlight. That’s no planet. The dips in the light have come in an irregular pattern, ruling out a simple orbit and hinting at multiple objects. In the absence of a well-understood, straightforward explanation, it’s reasonable to entertain exotic hypotheses.
It has long been proposed that technically advanced civilizations should be detectable by their works of “astroengineering.” The quirky character of KIC 8462852 resembles descriptions of “alien megastructures” that one can trace to science fiction going back at least to Olaf Stapledon in the 1930s. In 1960 Freeman Dyson described how advanced societies might surround their stars with enormous solar collectors. Stars hosting such “Dyson spheres” would appear dim in visible light but bright with the infrared glow due to waste heat.
Whatever the cause of the odd dips in the light from KIC 8462852, it’s clearly not such a Dyson sphere surrounding the whole star. But until scientists have convincingly explained what’s going on, is there anything wrong with entertaining the provocative thought that it could be some kind of huge alien construction?

How to Discuss Extraterrestrial Intelligence

Some scientists and pundits want to condemn that idea as ridiculous and unworthy of mention. But it would have been wrong not to consider this enticing possibility for such a strange observation. The correct posture, at this point, is to regard an artificial explanation as extremely unlikely — but not illogical or impossible.
Perhaps this provides a test case, because we have to learn how to talk about these things. In the decades ahead we will be observing more and more exoplanets with better and better instrumentation (see S&T's October issue for more on that topic). We’ll see some novel things, and when we don’t understand them, then biosignatures and even technosignatures are possible explanations, and we should consider them without going overboard with either skepticism or credulity. We have to be cautious — but if we refuse to consider outlandish and wonderful possibilities, we might miss something truly important.
The alien hypothesis has increased the interest with which scientists are scrutinizing this star. Out of this will come new knowledge, most likely not about aliens. Promising plans include making new visible, infrared, and ultraviolet observations. The next time the light of KIC 8462852 flickers we can inspect the material properties of the obscuring stuff: Is it dust? A swarm of comets? Or something seemingly artificial? Quite possibly it’s something nobody has thought of yet.
Perhaps someone will have explained the peculiarities of KIC 8462852’s light curve by the time this column appears in print. On the other hand, the mystery might endure for years, allowing numerous predictions to be made and tested. Imagine all the fiction, fantasy, nonsense, religion, and good science that a possible alien civilization might inspire if generations go by without a definitive answer. It would serve as a fluttering beacon reminding us that we have a lot to learn.