There is something poetic about humanity trying to discover other civilizations somewhere in the vastness of the Milky Way. There is also something pointless. But we won’t stop. There is no doubt about that.
One group of scientists believes we may have already discovered technological signatures from the technological civilization’s Dyson spheres, but the discovery is hidden in our vast troves of astronomical data.
The Dyson sphere is a hypothetical engineering project that only highly advanced civilizations can build. In this sense, “advanced” means the kind of almost unimaginable technological prowess that would allow a civilization to build a structure around an entire star.
These Dyson spheres would allow civilization to harness all of the star’s energy. A civilization can only build something so huge and complex if it reaches the second level of the world Kardashev scale.
Dyson spheres could be a tech signature, and a team of researchers from Sweden, India, the UK and the USA have developed a way to search for tech signatures of the Dyson sphere which they call Project Hephaestus. (Hephaestus was the Greek god of fire and metal.)
They publish their results in Monthly Notices of the Royal Academy of Sciences. Search titled “Project Hephaestus – II. Dyson field filters from Gaia DR3, 2MASS and WISE.“The lead author is Matthias Suazo, a PhD student in the Department of Physics and Astronomy at Uppsala University in Sweden. This is the second paper to feature the Hephaestus project. The first is here.
“In this study, we present a comprehensive investigation of Dyson fractional fields by analyzing optical and infrared observations from Gaia, 2MASS, and WISE,” the authors wrote.
These are large-scale astronomical surveys designed for various purposes. Each of them generated a huge amount of data from individual stars.
“This paper examines Gaia DR3, 2MASS and WISE photometric measurements from nearly 5 million sources to build a catalog of potential Dyson fields,” they explain.
Combing through all that data is a tedious task. In this work, the team of researchers developed a special data pipeline to work through the combined data of all three surveys.
They point out that they are looking for partially completed spheres, which would emit an excessive amount of infrared radiation.
“This structure will emit waste heat in the form of mid-infrared radiation, which, in addition to the level of completeness of the structure, will depend on its effective temperature,” Suazo and his colleagues wrote.
The problem is that they are not the only creatures that do this. Many natural things do this too Dust rings surrounding stars And nebulae. Background galaxies can also emit an excessive amount of infrared radiation and create false positives. It’s the pipeline’s job to filter it out.
“A specialized pipeline has been developed to identify potential Dyson field candidates with a focus on detecting sources that display anomalous infrared excesses that cannot be attributed to any known natural source of such radiation,” the researchers explain.
This flowchart shows what a pipeline looks like.
The pipeline is just the first step. The team is putting the list of candidates under further scrutiny based on factors such as H-alpha emissions, optical variability, and astrometry.
368 sources survived the final cut. Of these, 328 were rejected as a mixture, 29 were rejected as irregular, and four were rejected as nebula. There are only seven possible Dyson fields left out of about 5 million protozoans, and researchers are confident that these seven fields are legitimate.
“All sources are clear mid-infrared emitters with no obvious contaminants or signatures indicating a clear mid-infrared source,” they explain.
These are the seven strongest candidates, but researchers know that they are still just candidates. There may be other reasons why the seven are emitting excess infrared radiation.
“The presence of warm debris disks surrounding our candidates remains a plausible explanation for the excess infrared radiation in our sources,” they explain.
But the candidates appear to be M-type stars (red dwarfs), and debris disks around M dwarf stars are very rare. However, it gets complicated because some research suggests that the debris disks around M dwarfs form differently and appear differently. One type of debris disk called extreme debris disk (EDD) could explain some of the brightness the team sees around its candidates. “But these sources have never been observed for M dwarfs,” Suazo and his colleagues wrote.
This leaves the team with three questions: “Are our candidates exotic young stars whose flow does not change with time? Are the M dwarf debris disks of these stars extremely fractal luminosities? Or something completely different?”
“After analyzing optical/NIR/MIR photometry of approximately 5 x 106 Sources: “We found 7 M-type dwarfs that show an excess of infrared radiation of a fuzzy nature consistent with our Dyson sphere models,” the researchers wrote in their conclusion.
There are natural explanations for the excess infrared radiation coming from these seven, “but none of them clearly explain such a phenomenon in the candidates, especially since they are all M dwarfs.”
The researchers say that pursuing optical spectroscopy would help better understand these seven sources. A better understanding of H-alpha emissions is particularly valuable because they can also come from small disks. “In particular, analysis of the spectral region around H-alpha can help us eliminate or verify the presence of small disks,” the researchers wrote.
“Additional analyzes are certainly necessary to reveal the true nature of these sources,” the researchers concluded.
This article was originally published by The universe today. Read the Original article.
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