CAMBRIDGE, Mass., July 26 — The hunt for Dyson spheres, those hypothetical megastructures that would wrap a star to harvest its energy, is about to get a major technological upgrade. Multiple next-generation observatories coming online over the next few years will dramatically sharpen astronomers’ ability to detect the infrared signatures such constructs would leave behind. The practical upshot: what was once a fringe search is becoming a serious, systematic science.
The Infrared Advantage
At the heart of the search is the James Webb Space Telescope, launched on December 25, 2021, and operational since July 2022. Webb’s MIRI instrument gives it what researchers call unprecedented sensitivity in the mid-infrared range of 5 to 28 micrometers — exactly the wavelengths a partial Dyson sphere would radiate as waste heat. In plain terms, if a civilization built a swarm of solar collectors around its star, the structure would glow in infrared like a warm engine.
Webb is now the best tool to see that glow. But Webb won’t work alone.
The Nancy Grace Roman Space Telescope, scheduled for launch in 2027, will conduct wide-field surveys in the near-infrared. Here’s what that means: Roman will cover 100 times the sky area of Hubble in each image. Think of it like upgrading from a pair of binoculars to a giant panoramic camera — Roman can scan huge stretches of the Milky Way for odd infrared hotspots in a fraction of the time.
On the ground, the European Southern Observatory’s Extremely Large Telescope expects first light in 2028. The ELT will complement space-based observations with high-resolution spectroscopy, letting scientists analyze the chemical makeup of any suspicious infrared sources.
Together, these instruments form a kind of cosmic net, each catching different clues.
A Combined Effort
At a workshop at MIT, researchers laid out a concrete plan to use these capabilities. They outlined a prioritized observing list of 100 nearby black hole candidates — all within 500 parsecs — for which they will request James Webb’s Director’s Discretionary Time. That’s the fast-track scheduling slot for high-priority targets.
The plan also includes coordination with the Laser Interferometer Gravitational-Wave Observatory, or LIGO, which has been operational since 2015. LIGO detects gravitational waves from black hole mergers.
The idea: if a civilization built a Dyson sphere around a black hole (yes, that’s a concept out there), the merger remnants might show both gravitational-wave signatures and infrared excess. By cross-referencing LIGO’s merger candidates with Webb’s infrared eye, astronomers can identify the most promising objects to follow up.
What to Watch Next
The timeline is tight. Roman launches next year, the ELT the year after. Webb is already collecting data.
The MIT list of 100 candidates gives the community a clear target list. The practical upshot: within the next few years, we will either see something unmistakably artificial in the infrared sky, or we will place the strongest-ever limits on where such megastructures could exist.
Either outcome is a big step forward for the field.
