One of the most intriguing ideas is the Dyson spheres. A hypothetical megastructure, the brainchild of physicist Freeman Dyson in 1960, Dyson spheres represent a technological capability that could only be achieved by civilizations far more advanced than our own. Such civilizations could have the capability to construct megastructures that engulf their host stars and collect all their energy, which would classify them as Type II on the Kardashev Scale.
Recently, some research revisited the theory. A team of scientists from Sweden, India, the U.K., and the U.S. has proposed a strategy to hunt for Dyson sphere techno signatures, codenamed Project Hephaistos. This has resulted in some quite fascinating findings, as they have presented in their paper in the Monthly Notices of the Royal Astronomical Society. The present team, led by MatÃas Suazo doctoral student at Uppsala University data from the astronomical surveys of Gaia, 2MASS, and WISE. They have sifted through about 5 million sources in looking for Dyson spheres.
The authors used a dedicated data pipeline in searching for weird infrared excesses emanating from sources other than natural ones. The pipeline filtered out the objects that did not show the expected signature of Dyson spheres until it had narrowed the field to seven potential candidates. These candidates will be M-type red dwarf stars with infrared excesses difficult to explain through natural causes only.
In all these cases, it is still conceivable that the IR excess arises from a warm debris disk. Debris disks around M-dwarfs are rare, and besides, there are some studies suggesting that they form and present differently. Leaving the researchers with questions like, are these candidates strange young stars with flux that does not vary in time? Are these M-dwarf debris disks with extreme fractional luminosity? Or something completely different?
At the same time, another study conducted by the International School for Advanced Studies in Italy found 53 star candidates that have excess mid-infrared measurements. This, however, can easily be overcome since the results, although interesting, are not indicative; this could also be due to Extreme Debris Disks that result from the collision of planets.
David Hogg, a co-author of the second study, called for great caution in jumping to any conclusions about megastructures of aliens. He added that the most plausible explanation is still a natural one, which could be the aftermath of planetary collisions producing a huge amount of material.
The searches for Dyson spheres, on the other hand, are like hunting for a needle in a haystack, with the vast number of stars observed by Gaia, WISE, and 2MASS. Yet, their implications may be overwhelming. The discoveries, if confirmed, could change our way of understanding advanced civilizations and what they can do.
Follow-up observations, by perhaps the James Webb Space Telescope, could provide more insight into those candidates. As Jason Wright at Pennsylvania State University said, Either the candidates will be eliminated, or they will remain as interesting prospects that merit further investigation.
The search for Dyson spheres is fraught with difficulties and uncertainties, but at least the recent findings provide a tantalizing glimpse of what could be possible. Whether these infrared excesses result from advanced alien engineering or some previously unknown natural causes, the search for an explanation continues.