Dyson Spheres have been a tantalizing digression in the hunt for extraterrestrial intelligence. Recently, seven stars have been identified as potential candidates, with most of their radiation emitted in the infrared wavelengths.
Possibly this is the heat signature of an array of spacecraft around the star, but unfortunately a new paper has a slightly less exciting explanation; galaxies obscured by dust.
There are a number of ways to hunt aliens and one of them is to look for signs of large-scale projects in space. Enter the Dyson sphere. The idea was first proposed by Freeman Dyson in 1960 to describe how advanced civilizations would place energy collectors and even habitats around a star to harness its power.
Ultimately, such an infrastructure would likely surround the entire star, and Dyson reasoned that a signature would be detectable, such as excess infrared radiation.
The findings from Project Hephaistos revealed the seven M-type stars from a sample of 5 million stars detected by Gaia. The astrometric satellite has been used to map stars in the Milky Way and has been of great use for many studies.
Data from 2MASS (the Two Micron All Sky Survey) and WISE (the Wide Field Infrared Survey Explorer) were also used to identify the stars that appeared to exhibit the expected infrared excess.
In the recent paper by lead author Tongtian Ren and his team, they explore the project’s findings and delve into the possible nature of the candidate spheres. The team compared information from data from the Very Large Array Sky Survey (VLASS) and several other radio surveys of the sky. They looked for radio sources within 10 arcseconds of the candidates’ Gaia positions. Note that the full moon is 1860 arcseconds across.
Radio sources have been found for three of the candidates, named A, B and G. The accuracy of the sources was within 4.9, 0.4 and 5 arcseconds respectively and candidate G was found in several radio surveys. The team’s conclusion is that it is less likely that the seven stars are Dyson Spheres, but that they are some kind of extra-galactic phenomenon.
The most likely explanation is a distant galaxy obscured by dust! The presence of the dust would contaminate the infrared energy distribution in the spectra of the two objects. The other candidate, candidate B, is also thought to be a distant galaxy, but one that was within the line of sight of an M-type dwarf star.
Very similar to candidates A and B, candidate G has a spectrum that reveals radio-loud active galactic nuclei with superluminal jets extending out. It is likely that galaxies are distant quasars that emit enormous amounts of radiation, but the obscuring hot dust clouds obscure most radiation except infrared.
What about the other four candidates? To date, no suitable radio source has been found. That doesn’t mean the hot, dust-obscured galaxy model isn’t an adequate explanation, just that higher-resolution radio studies may be required.
Of course, it could also be that they really are technological spheres around distant stars. As much as I would like this to be true, there is no evidence for it yet.
This article was originally published by Universe today. Read the original article.
