Ever since we started gazing up at the night sky above us and were first aware that there was something out past the planet we live on we have looked to the stars and wondered what lies out there and whether we are alone in the universe. Philosophers, thinkers, and scientists alike throughout history have contemplated this since time unremembered, looking out to the vast sea of stars and pondering what might lie out there. In modern times, the stars themselves have given us strange clues about the nature of the universe, and have even at times hinted at the answer to our question of whether we are alone in the universe, and here are some of the most baffling and bizarre of all.
By far the most well-known weird star that has attracted stories of alien influences is the one called Tabby’s star, also known as Boyajian’s star and occasionally jokingly known as the WTF star. In 2015, scientists noticed unusual fluctuations in the light from a star with the rather dry and scientific sounding name KIC 8462852, located in the constellation Cygnus, about 1,480 light-years from Earth. Mostly it is just a rather ordinary F-type star, meaning it is slightly larger and hotter than our sun, but it would soon turn out that there was something definitely odd going on with this one. When various data collected on the star by NASA's Kepler space telescope, which is designed to detect exoplanets, astronomer Tabetha "Tabby" Boyajian, of Yale University, noticed that KIC 8462852 would sporadically dim in brightness by up to 22%, with such dips lasting anywhere from a few days to a week and with no obvious explanation. These dimming events did not seem to follow any discernible pattern or rhythm, and were not consistent with what one would expect to see with normal activity such as planets or dust crossing the star.
At the time it was rather bewildering, with no other known example of a star with such a unique and bizarre dimming phenomenon, and astronomers scrambled to try and explain it. Ideas included that it was an uneven ring of dust orbiting the star, fluctuating luminosity caused by uneven heat transfer or cooling of its photosphere, a swarm of disintegrated comet fragments, a field of asteroids, a series of giant planets with very large ring structures, a planetary debris field created by the remnants of a destroyed planet or moon, and others, but none of these fully fit the observed data, and without any other examples there was nothing to compare it to. But why have all of these boring explanations when you can have aliens? Perhaps the most controversial and at the same time fascinating hypothesis is that the dimming phenomenon is caused by some vast megastructure built around the star by an advanced, intelligent alien civilization, and here’s where things get interesting.
The main thrust of this idea is that the star could be surrounded by a hypothetical megastructure called a Dyson sphere, so immense that is partially or completely encompasses the star. First proposed in 1960 by the mathematician and physicist Freeman Dyson, these Dyson spheres would hypothetically be built around a star to harness its energy in order to power the technology and civilization of an extraterrestrial race, and they are theorized as taking the form of either a shell or scaffolding around the star, or globular swarms of giant solar panels orbiting it. Dyson saw this as almost inevitable for any advanced space going civilization, and would write:
One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.
In this scenario, the dimming could be caused by either the structure passing over the star’s face to block its light, creating the weird dimming, or by blasts of infrared caused by the radiating heat of the energy the aliens did not use, sort of like an energy exhaust port. Although this was just conjecture and really one of the last explanations scientists were entertaining, the media snapped it up and soon Tabby’s Star was all over the news as the star with aliens around it, and the search for extraterrestrial intelligence (SETI) was enamored enough with the idea to make it a prime target for searching for radio signals from aliens. They got no particularly odd signals from there, but considering we are seeing what the star looked like 1,480 years ago perhaps the aliens are just no longer there. After further analysis it is believed that it is likely caused by dust, debris, or the disruption of an orphaned exomoon, although scientists have not fully taken the alien megastructure hypothesis off of the table.
Interestingly, in later years it has turned out that Tabby’s Star is not so completely unique after all, and there have been a few others found with comparable unexplainable dimming patterns and events. One of these is the star KIC 4150611, which also had an odd flickering that hasn’t been explained, as well as the star EPIC 204278916, and the star VVV-WIT-07, with “WIT” amusingly standing for “What is This?”, which has mysteriously dropped up to 80% in brightness at times and has been called a “one in a billion object” by astronomers. More and more of these so-called “dippers” are being found all of the time. Edward Schmidt, an astrophysicist and emeritus professor of astronomy at the University of Nebraska-Lincoln, has extensively studied and mapped such stars, amassing a list of more than a dozen flickering stars like Tabby’s Star. These stars have different patterns and speeds of flickering, with some being “slow dippers” while others are “rapid dippers,” but all are so far beyond any conventional explanation. While Schmidt, like other astronomers, is trying to find rational answers, he has not dismissed the possibility that extraterrestrial intelligences could be to blame, and has said of these mysterious stars:
The thing that surprised me the most were these stars that had so many dips, the ones I called 'rapid dippers.’ I expected more occasional dips like Boyajian's star. I intend to try and follow up on the rapid dippers. One thing I noticed about them is that at least one seemed to be slowing way down in its dipping rate over the five years of coverage we have of it. It'd be interesting to find out what happened in its past, which may help give a better idea of what's going on with these stars. Many explanations for these stars is that something is passing in front of them, but the fact that the stars all fall within a narrow range of properties suggests that may not be it. Extraterrestrial intelligence is a low-probability explanation but it’s a possibility, and the SETI people ought to be looking at these stars.
What is going on with these stars? No one really seems to know for sure. It’s not only changes and anomalies in the brightness of these stars that suggest possible alien activity, but also the spectrum of their chemical elements. In 1960, Polish-Australian astronomer Antoni Przybylski was studying fast-moving stars in southern skies when he saw one that caused him to note “No star should look like that.” The star itself is hotter than our sun, as well as twice the diameter and four times the mass, but what surprised Przybylski was that it harbored a chemical spectrum that seemed to be impossible. Each star has a spectrum that shows the imprint left by its chemical components, and this can be detected with our instruments, but this star had a highly unusual mix of chemicals unlike any other. There were detected strontium and all 15 rare Earth elements, which is not so unusual, but there are also radioactive elements such as neptunium, plutonium, and curium, and the problem is that these radioactive elements should not be there. Jason Wright, a professor of astronomy and astrophysics at Pennsylvania State University, has explained of this, “These are all short-lived elements—they have half-lives of as little as a year or so. But the star has been there for millions of years, so the elements should have decayed away.”
So how did this happen? Some of the more rational scientific explanations include that these elements are being pulled up to the surface by magnetic fields and radiation pressure from below, or that they are somehow being bombarded onto the star by some outside cosmic phenomenon. It could also be that the star passed through an interstellar cloud which contained these elements, or that it devoured a planet that had a high concentration of them. Or it could be aliens. That's more fun, let's talk about that. There has been speculated the possibility that the presence of these anomalous elements could be because a spacefaring alien civilization is intentionally dumping them there. The hypothesis is that extraterrestrials from one of the star’s planets could be using their sun as a dumping ground for their radioactive waste, simply launching it into the star to dispose of it. The idea itself is not so far-fetched, as even here on Earth the idea of launching nuclear waste into the sun has been proposed occasionally in the past but was considered too expensive and impractical. Perhaps this race has figured out a way to do it, and that is why these elements are present there. Is this an alien garbage dumping ground or is there a more rational explanation? Who knows?
Perhaps even stranger than flickering stars and those with anomalous chemical balances are those stars that just seem to completely disappear for no explainable reason. Throughout historical and contemporary astronomical data, there have been around 100 stars or at least star-like celestial objects that have just sort of vanished without a trace under observation. They are called “red transients” or more colloquially “vanishing stars,” due to the fact that they typically start off as dim red dots, before experiencing a burst of brightness, up to several thousand times their starting luminosity and then completely disappearing as if they were never there. This usually happens within one hour, and it has been completely baffling astronomers.
A team led by Beatriz Villarroel, from Stockholm University and the Institute of Astrophysics of Canarias in Spain, discovered the phenomenon during a search of astronomical records looking for vanishing objects in the night sky in a project called Vanishing & Appearing Sources during a Century of Observations (VASCO). They have been studying the phenomenon of red transients since 2017 and have ruled out the explanations that they are asteroids, fast-moving stars, or stars that have just moved out of view. These are something else, although what that could be is up for debate. The thing is, stars don’t just spontaneously disappear. When a star dies off, it is a long, slow process of turning into a white dwarf star and fizzling out, or exploding into a supernova, which would definitely leave a trace behind. There is nothing to explain how one could just completely vanish without a trace within the space of an hour, and so scientists have been scratching their heads trying to find an answer. Some ideas are that the phenomenon is caused by massive solar flares emanating from red dwarfs, or that they were sucked into a black hole, but yet another explanation has of course been aliens. Villarroel would say in an article in the Astronomical Journal:
Unless a star collapses directly into a black hole, there is no known physical process by which it could physically vanish. If such examples exist this makes it interesting for searches for new exotic phenomena or even signs of technologically advanced civilizations.
Just like in the cases of the other strange stars we have looked at here, the scientists are not eager to embrace the alien theory, but nor can they completely rule it out considering how bizarre and unprecedented the anomalies are. In the extraterrestrial scenario, it is thought that it could be caused by either massive lasers or heat waste from Dyson spheres. It is certainly a strange possibility, but in the absence of any concrete answers it has not been waved away. Nevertheless, the team is trying to eliminate all other possibilities before deciding on the alien hypothesis, and a co-author of their paper on the matter has said, “But we are clear that none of these events have shown any direct signs of being ETI (extraterrestrial intelligence). We believe that they are natural, if somewhat extreme, astrophysical sources.” However, whenever dealing with some new and inexplicable astronomical phenomenon the possibility that it just might be caused by aliens is always eerily hanging in the background. Andrew Siemion, director of the Berkeley SETI Research Center, has explained of the hypothesis of extraterrestrial influence on these phenomena:
It’s a fine line. We have no evidence for technologically capable life anywhere else in the universe. So one doesn’t want to immediately leap to that solution for any newly discovered astronomical phenomenon. But at the same time, one doesn’t want to neglect the possibility that it could be going on.
What is going on with these stars? As we penetrate further out into the cosmos we are encountering more and more weirdness like this all the time, so what could it all mean? Is this just mundane forces that can be explained away with more knowledge? Is it it all just normal forces at work or is there something more to it? Could there possibly be alien intelligences out there that could account for these anomalies? While scientists like to shy away from such answers, they are still hesitant to rule it out, and through these mysterious stars we might just see that the universe could hold deep mysteries that could answer our question on whether we are alone in it all. Time will tell, and in the meantime, these stars keep doing their mysterious dance, in some ways just as impenetrable and inscrutable as they were at the dawn of our consciousness that they even existed at all.