Last year, science and science-fiction fans from across the internet simultaneously experienced a sensation of grand elation when it was announced that scientists were seriously considering the possibility that they had discovered what could be a Dyson Sphere encircling a star. The star in question, KIC 8462852, had been experiencing a period of unusual dimming over the past century, with light being blocked from it first being detected last October. In fact, more than 20% of its light had been blocked out by something exceptionally sizeable. For reference, an object size of the Solar System’s largest planet, Jupiter, would only block around 2% of the light emitted by said star.
Joy was escalated in August 2016 when a similar phenomenon was observed with the stellar object EPIC 204278916, a young star with a resolved disk. Over an observance period of 25 consecutive days (from 79 non-consecutive), dimming of up to 65% were observed. The variability was highly periodic and could be attributed with stellar rotation, leading some to hypothesise that the irregular dimming was from a warped disk with an eccentric orbit.
As a result of both of these observations, it was posited that an advanced alien civilisation could have built megastructures around the stars to harness the energy. This concept has long been known to the communities of both Astronomy and Science Fiction as the Dyson Sphere, named after the man who fleshed out the concept, Freeman Dyson, although it first appeared in the novel Star Maker by Olaf Stapledon. The megastructure would be
designed to encompass a star, and capture its rays, thereby granting the structure the ability to maximise the amount of energy harnessed. As a brute example, you would essentially wind up with a solid shell encompassing a star, with cities built on its interior. Doing so would meet the needs of advanced civilisations and would see to a ready solution regarding problems of space and sustainable habitation, as long as the species who built it had both the patience and resources, that is. In KIC’s case, the type most befitting of it would be a Dyson Swarm (essentially a dot-to-dot variation of a Sphere).
However, there are numerous problems with both alien hypotheses. After a two-week severe of KIC by SETI, no technology-related radio signals were detected, any narrowband signals, or even any medium-band signals, the ones most common to human use. In addition, the archival VERITAS gamma-ray observatory found no pulsed optical beams which could be associated with the star, thereby making the chances of alien life being involved with the star’s dimming almost negligible, due to the fact that, if there are no extraordinary emissions of any kind, it is unreasonable to believe that we should accept the
idea that there are those which would be responsible for such emissions. Likewise, with EPIC, the star has been noted to possess an orbital disk of suspended matter, or cometary-like objects, bound in eccentric orbits to the star, which could, after further observation, do away with the need for a megastructure. Indeed, disks like these have been noted in the past to have caused mistakes like these to be made, due to their occasionally odd behaviour and construction.
As for KIC, we have a number of potential explanations which have been levied, each have their flaws and the mystery is still officially unsolved. For example, it has been suggested that, if the star is younger than its speed and position suggests, then it is likely that material is still coalescing around it, which will either be absorbed or thrown into space at a later date. However, the chances of this are low, since a spectroscopic study of the system found no evidence of coalescing material within the necessary distance. Another possibility is that a massive collision would create warm dust which would glow in infrared wavelengths, although this has not been detected.
“one proposed explanation which is still out there is that the reduction in light is caused by a cloud of disintegrating comets orbiting the star in an ecliptic pattern.”
However, one proposed explanation which is still out there is that the reduction in light is caused by a cloud of disintegrating comets orbiting the star in an ecliptic pattern. Under this scenario, gravity from a nearby star could have potentially caused comets from KIC’s Oort Cloud (think of an outer rim asteroid belt except far, far larger) to fall into the system. This hypothesis is supposed by the existence of a Red Dwarf star only 885 AU (the distance between the Sun and Earth is 1 AU) away. However, the notion this would require an immense amount of matter to be shunted, and would likely need a far larger star to achieve this event, although alternate collisions or bodies have been ruled out due to the lack of evidence.
As of this moment, the likelihood of both results being rather, well, dusty, is seen as a far greater likelihood than the possibility that we have found super-advanced aliens. However, firm conclusions relating to both stars have not yet been reached, so it is not by any stretch safe to say that the book has been closed on aliens. With the astronomer Jason Wright and colleagues set to observe KIC next month as West Virginia’s Green Bank Telescope, we should hopefully have a lid placed on this mystery in the next few months. Just don’t hold your breath.