Is that alien megastructure just a galaxy hiding in plain sight?
In short: Scientists have scanned millions of stars looking for Dyson spheres—massive structures built by advanced civilizations to harvest a star's entire energy output. While these hypothetical megastructures would be the ultimate sign of extraterrestrial life, recent observations suggest we might be misinterpreting some of the universe's most distant neighbors.
A Dyson sphere, first proposed by physicist Freeman Dyson in 1960, is a hypothetical megastructure designed to capture radiation energy. Because these structures would likely emit waste heat, astronomers look for an 'infrared excess'—radiation in the mid-infrared spectrum that shouldn't be there from a normal star. Researchers believe red dwarfs and white dwarfs are the most likely candidates for these structures because they are small, long-lived, and would require less construction material than a structure around a sun-like star.
However, identifying these technosignatures is incredibly difficult. In a recent search involving Project Hephaistos, researchers used NASA's James Webb Space Telescope to examine two specific M-dwarf stars identified from a survey of 1 million stars within 1,000 light-years of Earth. They were looking for the specific infrared signatures of a Dyson swarm—a collection of many orbiting structures rather than one solid shell. Instead of finding alien technology, the telescope revealed that the infrared signals were actually coming from background galaxies.
One of these candidates was identified as a 'Hot DOG' (Hot Dust Obscured Galaxy), while the other showed a spectrum consistent with a dusty starburst. This highlights a major hurdle in the search for extraterrestrial intelligence: cosmic objects can often mimic the signatures of advanced technology. While the search for Kardashev III-type civilizations continues, these findings remind us that the universe is full of natural phenomena that can baffle our understanding of physics and astronomy.
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Sources
- Summary by Intellect · source: NASA Found a Strange Star! Is This a Dyson Sphere?
- Also: NASA's Webb telescope rules out two new Dyson sphere candidates
- Also: 7 potential
- Also: www.sciencedaily.com — The galaxy’s coldest “stars” may actually be alien megastructures
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