Dyson spheres: A powerful vacuum or an alien megastructure newly discovered in our galaxy?

When people hear “Dyson sphere,” their first thought is probably a heavy-duty vacuum. They certainly don’t think of a megastructure surrounding and harnessing a star’s energy with the purpose of fueling a highly advanced extraterrestrial civilization.

But that’s exactly what it is, at least in theory.

Now, some scientists believe they might have found not one, but seven in the Milky Way. Project Hephaistos, named after the Greek god of fire and metalworking, published research on May 6 claiming they may have found seven red dwarf stars surrounded by Dyson spheres in our galaxy.

In 1960, theoretical physicist Freeman Dyson hypothesized in an article that aliens looking for a more powerful energy source could construct a gigantic device around a star using essentially a shell of solar panels to absorb starlight. This idea stemmed from the belief that aliens, as they become more technologically savvy, would need an incredible amount of energy to support themselves.

Scientists believe if extraterrestrials were able to construct Dyson spheres, they would be able to achieve out-of-this-world feats, like the transmutation of objects, interstellar travel and the ability to control the climate of their home planet. They might even be able to move their entire solar system to a better location.

A Dyson sphere’s close proximity to a star means that, if they exist, they will heat up and emit infrared energy that could be observed by humans on Earth.

Red dwarf stars are the smallest kind of star and account for 70% of all stars. This would make them the easiest stars to build a Dyson sphere around. The original study included 5 million stars as candidates for the sphere. After a series of filtered tests, that number dropped to just seven.

Scientists used Wide-field Infrared Survey Explorer (WISE) to, “measure the kind of heat that would come off of Dyson spheres,” said Jason Wright, a professor of astronomy and astrophysics at Penn State. Wright was a collaborator and coauthor on Project Hephaistos.

They also used the Global Astrometric Interferometer for Astrophysics (GAIA) and an astronomical survey of the sky in infrared called the Two Micron All Sky Survey also known as 2MASS. All three provided photometric data, but GAIA measured the distances of stars to help filter out the sources that WISE detected that could’ve been Dyson spheres but were actually distant galaxies.

“All stars give off infrared radiation according to their temperature,” Wright said. The seven Dyson sphere candidates “look like perfectly ordinary stars that, for whatever reason, have too much infrared emission.”

All of the potential Dyson spheres are within 1,000 light years of Earth. The closest one is 466 light years away, or about 2.74 quadrillion miles away. That’s 16 numerals for the curious.

For reference, the Milky Way galaxy is approximately 100,000 light years across in diameter. According to NASA, there are 100 billion stars on the low-end and 400 billion stars on the high-end just in our galaxy. The nearest galaxy to us is Andromeda, which is 2.5 million light years away.

Paul Yost, the vice president of the Spokane Astronomical Society, said the first time he heard about Dyson spheres was as a junior in high school in 1978. Since then, he has been interested in the possibility of advanced extraterrestrial life. Yost graduated with a degree in mathematics from Boise State University in 1985 and has worked as a computer programmer for a small steel company in Spokane for the last 30 years.

“There’s so many stars, it seems like there ought to be a pretty good chance that there is one,” Yost said.

Others are more skeptical.

Adam Fritsch is an associate professor of physics at Gonzaga University and is a consulting editor for the American Journal of Physics. His work revolves around nuclear astrophysics, or what happens inside stars. He highly doubts that Dyson spheres exist, at least in our galactic neighborhood.

“It’s very, very unlikely,” Fritsch emphasized. “Very unlikely, but it is legitimate in a certain sense. The fact that a small group of scientists are doing those searches, does make sense. But I don’t think it would be appropriate to dedicate too many resources to it because resources are finite and there’s other bigger ticket items to look at with telescope time.”

And he’s right. Telescope time is in high demand. Scientists involved in the project would like access to the James Webb Space Telescope to take observations of the Dyson sphere candidates, but there are plenty of other scientists competing for telescope time to conduct their own research.

Project Hephaistos doesn’t provide concrete proof for the existence of intellectually advanced extraterrestrials. A recent paper, “Background Contamination of the Project Hephaistos Dyson Spheres Candidates,” points to either debris in front of the star or hot DOGs as the real culprit behind the unusual infrared signatures. No, not actual hot dogs, but dust obscured galaxies (DOGs). These types of galaxies are surrounded by warm dust clouds that emit excess infrared radiation equivalent to what a Dyson sphere would.

“If you have this chance alignment of a foreground star and a background hot DOG, then their combined light … you put it together and it looks like a Dyson sphere,” Wright said.

Michael Garrett, the Sir Bernard Lovell Chair in Astrophysics at the University of Manchester and an author of the above mentioned paper, had his student, Tongtian Ren, use a different kind of wavelength, radio, to verify the seven candidates. He and his student found radio sources aligning in the same general area for three out of the seven proposed Dyson sphere candidates.

“When you see radio sources, next to those stars, then it’s a telltale sign that we’re talking about background galaxies lying very close to these stars.” Garrett said.

Galaxies produce a large amount of radio emission naturally, while stars’ radio emissions are very weak and difficult to detect. Dwarf stars aren’t supposed to have any identification with any kind of radio emission, Garrett said.

“There’s still four candidates that don’t have radio emissions,” Garrett said. “So, who knows what they are. But the fact that three of them have radio emissions and are probably being contaminated by background galaxies, you could extrapolate to say that possibly the other four are maybe the same.”

The distance between our galaxy and other galaxies makes it nearly impossible to determine the root cause of the infrared signatures coming from the four remaining candidates until deeper observations are done. Wright said high contrast imaging to point out background galaxies or an infrared spectrum using the James Webb Space Telescope would presumably confirm or deny the validity of the four remaining Dyson sphere candidates.

“It’s a pity, because I’ve spent a lot of time looking for them,” Garrett said. “I don’t think there’s much evidence for Dyson spheres, and I think that’s kind of a worry in a sense … It’s really difficult to stop your Dyson sphere and your computers and all the rest of it; it’s really difficult to stop them radiating in the infrared. We have telescopes that are sort of at the level where we can begin to start detecting this phenomenon, not just in the Milky Way, but also in other galaxies. They, in principle, should be able to detect this kind of thing. So far, there’s really no evidence that there are Dyson spheres in our galaxy or in others.”

Single-celled life has existed on Earth for 3.5 billion years. Only in the past 600 million years has multicellular life roamed the planet. Humans and their early ancestors have been around for only about 6 million years. This means that if aliens do exist, they’re most likely still in their infancy. If they existed in the past, perhaps they were only around for a blip in the cosmic calendar. Given humankind’s own track record, it’s possible that aliens are programmed for self-destruction and a certain technological threshold exists that’s impossible for them to surmount. The discrepancy between the likelihood that intelligent alien life exists and the lack of evidence for such, is also known as the Fermi paradox.

So, we haven’t found aliens yet and probably won’t for a while. But what if humans were able to make Dyson spheres?

“We ourselves are some centuries away from such engineering feats,” Yost said via email. “Consider, Robert Goddard published the math for achieving low earth orbit in 1919. Jules Verne’s story about travel to the moon inspired a lot of people to consider the possibility – and this was written in 1865, a century and four years before Neil Armstrong left his famous boot print.”

Yost and Fritsch believe humans would have to completely deconstruct Mars for the required resources, like silicone and glass, needed to build solar arrays on a Dyson sphere. Freeman Dyson said it would take all of Jupiter to make a Dyson sphere.

Because of this, human-built Dyson spheres will remain purely science fiction for at least another couple centuries. Other alternative energy sources are being developed that are much more feasible. Wind, solar, geothermal, and nuclear fusion are all potential energy sources that we have yet to fully tap into.

Nuclear fusion has seen dramatic advancements in recent years, but Fritsch said the biggest question that remains is can we get more energy out than we put in? Implementing fusion across our power grid is still a challenge scientists are tackling, along with the problem of storing the renewable energy we generate.

“An advancement in batteries is a very important aspect of any kind of renewable energy source, whether it’s solar, whether it’s wind, whether it’s fusion. You need to also be able to store that energy,” Fritsch said.

According to ourworldindata.org, the Earth has approximately 139 years of coal reserves left. If we burn coal until we run out, however, we will most likely have dangerous levels of CO2 in our atmosphere. Other fossil fuels will run out much sooner. Oil and gas have around 50 years or less until we run out. These figures are subject to change depending on possible coal discoveries. Not to mention the environmental impact that comes from the 35 billion tons of carbon dioxide released each year into the air that takes thousands of years for the Earth to absorb.

“I’m very bullish on solar and maybe other ones like wind, or fusion,” Fritsch said. “We only need one of them to work in some sense and we don’t know which one that’s going to be … Hopefully it pays off.”