Are the Milky Way’s coldest stars actually strange giant structures? A new study explores
Some of the coldest objects currently listed as stars in the Milky Way may not be stars at all. A new study by astrophysicist Amirnezam Amiri of the University of Arkansas suggests that these extremely cold objects could instead be giant energy-harvesting structures built by advanced alien civilizations.
According to the research, these objects are consistent with the expected behavior of engineering systems that collect the star’s energy and release the remaining heat in the form of infrared radiation.The study is scheduled to be published in the journal Cosmos, and it presents a new mathematical method to search for these possible strange structures. This idea was first proposed by physicist Freeman Dyson in 1960. Instead of a single giant shell surrounding a star, modern scientists now prefer the idea of a star. ‘Dyson swarm“, It consists of millions of separate solar collectors orbiting the star.
The researchers believe this design is much more practical than a solid sphere, which would be nearly impossible to build.According to Amiri’s study, red dwarfs and white dwarfs would be the best stars for an advanced space civilization to build such a system around.
Red dwarfs and white dwarfs can be the best choice
Red dwarfs are the most common stars in the Milky Way. They burn their nuclear fuel very slowly, allowing them to remain stable for trillions of years. This gives any advanced civilization plenty of time to build and maintain a large energy harvesting system.
Because red dwarfs are much smaller than stars like the Sun, they also require much less material to surround them.
“A Dyson swarm could orbit a red dwarf at a distance of about 0.05 to 0.3 astronomical units, requiring much less building materials than around a larger star like the Sun,” Amiri wrote.White dwarfs could be better. These are the dense remains of Sun-like stars after they have reached the end of their lives.
Although they shrink to only about 1% of their original size, they continue to release energy for billions of years. Due to its small size, a Dyson swarm can only orbit a few million kilometers above the surface, reducing the amount of material needed to collect the star’s energy.
I’m looking for an unusual heat signature
A Dyson swarm would completely change the way a star appears in a Hertzsprung-Russell (HR) chart, which astronomers use to compare a star’s temperature with its brightness.The idea is simple. A Dyson swarm would absorb most of the visible light from its star, use that energy to power an advanced civilization, and then release the unused energy as infrared heat. The total amount of energy will remain the same, but a much smaller amount will be seen as visible light.
As a result, the object will shine brightly in infrared light while appearing unusually dim in visible light. In the HR diagram, it will move to the cooler part of the diagram even though its total energy production will remain unchanged.This creates a very unusual signature. A normal red dwarf has a surface temperature of about 3,000 K, while a fully developed Dyson swarm could reduce its apparent body temperature to about 50 K. This would make it cooler than any normal star and put it in an empty part of the HR chart where astronomers expect to find possible signs of alien technology.
What scientists are looking for
Amiri’s research also explains how scientists can distinguish between a Dyson swarm and a natural dust cloud.Young stars and dying stars are often surrounded by thick disks of dust, which also glow in infrared light. However, these dust clouds leave behind clear chemical signatures, including emissions from silicate minerals.Dyson’s flock will look very different. Instead of dusty materials, they will produce a much cleaner infrared spectrum because they will be made of organized structures rather than natural debris.The gaps between the millions of orbiting solar collectors would create another piece of evidence. As the complexes move around the star, they block different amounts of light at different times, causing irregular changes in brightness. These patterns will be very different from the regular variations seen in naturally variable stars.
What a virtual Dyson Swarm system will look like
Astronomers are already searching for these subtle signs. The James Webb Space Telescope, with its powerful infrared instruments, is one of the main instruments used.
Meanwhile, projects like the Hephaestus Project are analyzing millions of ancient observations from missions including the Wide Field Infrared Survey Explorer (WISE).In May 2024, the Hephaestus Project identified seven potential candidates for Dyson’s field through a survey of about five million stars, all centered around red dwarfs. One candidate was later ruled out after researchers discovered that a distant supermassive black hole lined up behind the star. This leaves five candidates still under consideration.The new Amiri model gives astronomers a clearer way to test these objects and determine whether they are simply unusual natural systems or potential signs of advanced space technology.
