The latest Swedish-led search for technosignatures in the form of Dyson Spheres has again come up empty-handed. The two latest stellar candidates in the hunt for such hypothetical extraterrestrial technology have been eliminated as Dyson Spheres.

Project Hephaistos, an Uppsala University-led initiative, used NASA’s James Webb Space Telescope to observe two new Dyson Sphere candidates. The Webb telescope took imaging and spectroscopy of two M-dwarf stars, as noted in two papers recently submitted to the journal Monthly Notices of the Royal Astronomical Society (MNRAS).

Dyson spheres are hypothetical megastructures constructed around stars to harvest radiation energy, possibly for the purpose of powering habitats, vessel propulsion, computing or transmitting long-range signals, the MNRAS authors note. The primary technosignature of such structures is the waste heat emitted, usually assumed to be detectable as excess radiation in the infrared, they write.

Most of such putative waste heat emissions would show up in the mid-infrared spectrum.

We find that the infrared excess does not originate from Dysonian megastructures, or other radiation mechanisms close to these stars, but from background galaxies projected to be within an arcsec of the M dwarfs, the MNRAS papers’ authors write. One has a mid-infrared spectrum consistent with being a Hot Dust Obscured Galaxy (Hot DOG), they note.

The other galaxy has what the authors call an extended morphology with bright knots and a spectrum consistent with a dusty starburst, they note.

These latest results point out the extreme difficulty of looking for techno signatures of any sort. That is, whether they be from super advanced Kardashev III or IV-type civilizations capable of harnessing whole galaxies, or a Kardashev I- or II-type civilization, capable of harnessing the energy of a single star.

This is follow-up with the Webb telescope to observe two stars that we identified in a survey of some one million stars within about 1000 light years of Earth, Andreas Korn, a senior lecturer in astrophysics at Uppsala University in Sweden and a Project Hephaistos team member, told me in Stockholm.

That survey was first conducted with the European Space Agency’s Gaia satellite as well as NASA’s WISE (Wide-field Infrared Survey Explorer) mission. The aim was to look for stars that have surprisingly low fluxes in the optical and surprisingly high fluxes in the infrared.

As Korn notes, such a combination is seen as a potential technological signature of an extraterrestrial civilization, referred to in general terms as a Dyson Sphere.

The two stars that were initially the most promising were an estimated few billion years old; relatively faint M dwarfs stars of around 15th magnitude.

Nothing that you can observe with the naked eye, says Korn.

Eventually, even if you are using this Dyson Sphere energy to do computing, the energy will be transformed and emitted in the infrared as waste heat, says Korn. But this is the signature that we were looking for: a star that is a little bit too faint in the optical and has substantial amounts of waste heat in the infrared, he says.

But what they found was a superposition of run-of-the-mill M dwarfs and two background galaxies.

WISE gives us just a coarse image, and that’s why the photons from the background galaxy and the M dwarfs were blended together so we couldn’t tell them apart, says Korn. But with the Webb, we can tell the two apart and do a separate analyses, either from the galaxy or from the foreground M dwarf, he says.

What’s Next?

The most immediate problem in any future search is as the MNRAS papers’ authors note, a substantial fraction of the Project Hephaistos Dyson Sphere candidates appears to be contaminated by background galaxies. But proposed mid-infrared telescopes in the 2030s could provide higher-resolution data over wide areas, the authors write.

So, there will be infrared surveys that have better spatial resolution coming online in the 2030s that may eventually solve that problem, says Korn.

Another example of a partial Dyson Sphere. Credit: Kevin Gill/via Wikipedia

As for the handiwork of civilizations capable of modifying whole galaxies?

On a galactic scale, astronomers would look for objects that again are unexpectedly fainter than expected in a manner that can’t be explained by known, completely natural astrophysics.

The idea of Dyson Spheres around main sequence stars remains an intriguing concept. But would a planetary system even have enough raw material to build such monstrosities?

A Dyson Swarm

You don’t have to build a solid structure; a Dyson swarm of satellites could fulfill the same purpose, says Korn. It would collect less energy than a solid sphere, but it could still collect more energy than available on a planetary scale, he says.

If such hypothetical Dyson satellites were orbiting the star in a manner that would be detectable, this would lead to some variability in the target star’s luminosity.

The Bottom Line?

There are many sources of variability in the physical world, but if you see that there was a periodicity to the variability, then you could potentially constrain the morphology of an artificial mega structure, says Korn.

Sources:

Andreas Korn

MNRAS paper

MNRAS paper

Five Los Angeles-area members of Congress urged the Trump administration Wednesday to speed up $2 billion in transportation funding that the lawmakers said is critical to assuring that athletes, officials and fans can move easily around Southern California during the 2028 Olympic Games.

The call came at an informal hearing by House members in West Hollywood, where local transportation officials said the money is needed to deploy 1,700 extra buses and to create high-speed lanes on streets and freeways during the Summer Games.

“We are certainly insisting that the federal government provide the resources that Los Angeles needs to make these Games a success,” said Rep. Laura Friedman (D-Glendale). “We know we need $2 billion to give the seamless, wonderful experience that everybody expects when they come for these Games. And so far, the federal government [has not] released anything really.”

The statements by the House members came on the same day that L.A. City Controller Kenneth Mejia demanded that LA28, the private nonprofit overseeing the Games, provide more detailed reports on its finances.

LA28 has complied fully with only two of nine requirements of a contract with the city known as the Games Agreement, Mejia said in a news release. Missing documents include comparisons of revenue from sources including ticket sales and sponsorship deals against financial projections, bank statements, schedules and budgets for venues and the identity of contractors and the dollar value and purpose of contracts.

Mejia said the city had been ill-advised to agree to be the financial backstop, should the Games lose money. Olympic officials have insisted that will not happen. But Mejia said he needs more than promises.

“We all want a successful 2028 Olympic Games,” Mejia said in a statement, “but its success cannot be at the cost of transparency and accountability to L.A. taxpayers.”

LA28 officials declined to comment on the controller’s statement.

The meeting at West Hollywood City Hall by the five lawmakers — all Democrats — is just the latest effort by local officials to coax financial support out of President Trump and Republicans, who control the House and Senate.

Though omnibus legislation approved last year promised $1 billion in security funding to make the 2028 Games secure, none of that money has arrived in Los Angeles.

Without federal support, the Games won’t be the showcase event for Los Angeles, California and America that most people are expecting, said Friedman and the four other Democrats she called together for the panel.

A White House official rejected claims that Trump’s team isn’t doing enough to support the 2028 Games.

“The White House has been proactively working and meeting with local LA Officials, Members of Congress, and the Organizing Committee at the highest levels to discuss these issues,” the official said, adding that, although the talks were “in the early stages, the Administration is actively doing its part to ensure the resources needed are secured to ensure this is the greatest Olympics in history.”

Officials at LA28, the nonprofit overseeing what will be L.A.’s third Summer Games, have pursued a less confrontational approach in trying to secure cooperation, and funding, from Republicans in Washington.

“The president and the administration have been supportive of LA28 every step of the way,” Marisa McGrath Liston, the group’s top spokesperson, said in a statement late Wednesday. “We look forward to our continued partnership as we look to welcome athletes and visitors to the greatest city in the world.”

Rep. Sydney Kamlager-Dove (D-Los Angeles) said this summer’s World Cup soccer matches in L.A. held out the promise the city can successfully mount world-class sporting events.

Kamlager-Dove, who represents the district that includes the Los Angeles Memorial Coliseum and other venues, noted that she and more than three dozen elected officials previously wrote to Transportation Secretary Sean Duffy demanding more federal support.

“I have to reiterate Los Angeles may be the physical host of the Olympics, but it is the United States of America that is in fact hosting this Olympics,” she said. “We shouldn’t have to wait this dang long waiting for this money that we deserve.”

Officials at L.A. Metro, who operate the region’s biggest bus and rail lines, previously told the board overseeing their agency that neither Washington nor the Democrat-ruled state Capitol in Sacramento has come through with transportation funding. They said the funds are needed as soon as possible for priorities like securing an additional 1,700 buses to augment the 2,100 already in the system and beginning work on special road and freeway lanes designed to assure that competitors and officials make it to venues on time.

The Metro officials said the Republican-controlled House had “kicked the can down the road,” rather than approve an initial $875-million outlay for 2028 Olympic transportation. When California legislators approved their 2026-27 budget this summer, it did not include another $379 million L.A. Metro had requested for infrastructure improvements.

The transit agency said that if delays continued much longer, it would endanger their ability to get L.A. and neighboring communities ready in time. Kamlager-Dove’s letter to Duffy said that the fiscal year that begins Sept. 1 would be the last chance to get the money in place soon enough to be useful.

Jennifer Vides, chief customer experience officer for L.A. Metro, said the World Cup proved L.A. can be “more than a car-centric metropolis,” adding: “We are a transit city, and we are ready for the global stage. “

She said that ridership on L.A. Metro trains and buses increased by 4.4 million in June and July, compared to the same months in 2025. And more than 70% of riders surveyed about their experience deemed themselves “very satisfied.” That bodes well for use of transit, rather than cars, when the Games arrive in July of 2028, Vides said.

But several of the House members said the agency and others providing bus service need to make sure that there is enough parking, shade, water and other necessities so that customers are willing to ditch their cars.

Rep. Ted Lieu (D-Torrance) praised the cleanliness, efficiency and low cost of a bus he rode from Torrance to SoFi Stadium for a World Cup Game, but not the 15-minute walk he said it took from the drop-off point to the stadium.

Lieu expressed concern that security perimeters would be so large during the Games that drop-off points would be even more distant, necessitating walks of up to half an hour, discouraging fans from taking buses.

Bill Scott, chief of Metro’s in-house police force, said security perimeters have not yet been set for SoFi and other 2028 venues. “There are a lot of security concerns that we’re still hashing out, but the goal is the shorter of those options that you present,” Scott said.

Rep Maxine Waters (D-Los Angeles), whose district includes Inglewood’s SoFi Stadium, said she is concerned that businesses will be displaced by some of the transit and parking plans. Like other local lawmakers, she said she also wants to see more done to assure that jobs and other economic benefits from the Games help her constituents. A similar view was expressed by Rep. Judy Chu (D-Monterey Park), who represents a San Gabriel Valley district.

To drive home their appeal for funds from Washington, the lawmakers displayed a board that showed the amount of money sent by the federal government to support previous games. It showed $1.82 billion went to Atlanta for the 1996 Summer Olympics and $2.61 billion to Salt Lake City to host the 2002 Winter Olympics.

Another sign, behind the panelists, highlighted a comment by Duffy to Congress in July of 2025: “I stand willing and ready to partner with you to make sure this goes well and we showcase this great country.”

Laura Rubio-Cornejo, general manager of the L.A. city Department of Transportation, said the federal funding would also help assure that the Olympic transit push doesn’t take away from buses and trains that get everyday Angelenos to work, schools and other destinations.

“The less federal funding there is to support that program, it puts a strain on our local roads and freeway system,” Rubio-Conejo said, “and then we’ll be looking to other municipal operators to really pitch in at a greater level, and thereby sacrificing the services to everyday Angelenos, who still need to get to work and school. And so that I think is the risk that we’re seeing.”