Last week, the internet was abuzz with the news of a mysterious object orbiting a distant star 1,500 light-years away that was blocking a huge amount of its light. With no obvious candidate for what the object could be, one scientist suggested the very faint possibility that it could be artificial in nature – yes, made by aliens.
“Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build,” Jason Wright, an astrophysicist from Pennsylvania State University, told The Atlantic. Wright wasn't directly involved in the study, which has been published in Arxiv, but made his comments after discussing the findings with lead author Tabetha Boyajian. Is he right, and if so, what could it be?
Wright has since clarified his comments and said that such a theory is extremely (emphasis on “extremely”) unlikely. But it’s intriguing, nonetheless – if not least to spark discussion as what might be out there. After all, there are hundreds of billions of planets in our galaxy, itself one of hundreds of millions of galaxies in the known universe. It seems doubtful that we are the only planet with life on it, although why we have not found other intelligent life yet is a mystery, known as the Fermi Paradox.
The star in question is KIC 8462852, an old star about 1.5 times larger than the Sun. Using the Kepler space telescope, a team of astronomers found that its light dipped by up to 20% on several occasions due to the orbit of a vast object that would have to be almost half the star’s size. What’s more, these huge dips occurred at random across the 1,600 days the star was observed.
Owing to the age of the star, the object must be relatively new, or it would have been consumed by the star’s gravity. The object cannot be a star, as it is not emitting light nor is it circular. It is also unlikely to be a planet, owing to its irregular orbit. So, what is it?
In the paper, the leading suggestion is that it is debris left from comets breaking up around the star. This would be expected to produce large amounts of infrared radiation, though, owing to the scattering of dust around the star, something that was not observed. This led Wright to suggest the other, more outlandish theory – that an alien civilization could be the cause, or more specifically, a Dyson sphere.
A Dyson sphere is a structure that harnesses a star’s energy for use by a civilization, sort of like solar power but on a massive scale. It would be composed of hundreds or thousands of spacecraft, often referred to as a Dyson swarm, that would theoretically be large enough to block out a significant portion of a star's light.
A Dyson Sphere, illustrated, is one vageuly possible explanation. Vedexent.
It’s estimated that as a civilization gets more and more advanced, it will require more and more energy to thrive. Some consider a Dyson sphere the best way to gather this energy, labeling the civilization a type II on the Kardashev Scale (for reference, we are at 0.73). However, a recent separate study to find such structures around stars proved fruitless.
Indeed, if this were a Dyson sphere, it would be producing large amounts of infrared radiation, something not apparent at the moment. The researchers are planning to use telescopes to observe the star in greater detail and see if it is producing any unusual signals, but for now there doesn’t seem to be anything untoward. One possibility is that the Dyson sphere is a remnant of an ancient civilization that is now extinct, or elsewhere, and the machines are defunct, simply left to orbit the star and block its light.
Perhaps it could also be some other type of alien structure. The possibility has tantalised the SETI (Search for Extraterrestrial Intelligence) Institute in California enough to take a closer look at the star with the Allen Telescope Array as of today. We’ll have to wait and see if they find anything.
But this is all very unlikely. We’re definitely not suggesting for certain this is some kind of alien technology. Indeed, similar speculation occurred in the past when pulsars – rapidly rotating neutron stars – were discovered and mistaken for possible signs of artificial intelligence. Their existence had not previously been theorized; perhaps this latest discovery is, too, a new natural phenomenon.
Even if this turns out to be nothing more than a swarm of dead comets, or something else, that would still be of huge interest. But, here or elsewhere, we’re surely going to find some sign of another intelligent race eventually. If not, as the Fermi paradox famously states, then where is everyone?