CAMBRIDGE, Mass., July 26 — A theoretical energy source first sketched out in 1969 is now being re-examined as a real possibility for future power generation, one that could make black holes not just cosmic mysteries but potential fuel stations. At the heart of the idea lies the Penrose process, named for the Nobel Prize-winning physicist Roger Penrose, who described how a rotating black hole could be tapped for energy.
Penrose showed that a particle entering the ergosphere, the region just outside a black hole’s event horizon where space-time itself is dragged along, could split in two. One fragment would fall into the black hole, while the other would escape, carrying away more energy than the original particle brought in.
It is a subtle, elegant mechanism, and for decades it remained a largely theoretical curiosity.
From theoretical curiosity to engineering blueprint
Now, researchers at a workshop held at the Massachusetts Institute of Technology have been reviewing models that take the Penrose process a step further. The idea is to build a Dyson sphere — a vast shell of energy-collecting structures — around a black hole. This sphere would not only capture energy from the Penrose process but also from the accretion disk, a swirling mass of material heated to millions of degrees as it falls toward the black hole.
The sphere could even harvest Hawking radiation, the faint particle emission predicted by Stephen Hawking in 1974. Such a structure would radiate waste heat as infrared light, producing a spectral signature that is distinct from any natural object.
That signature is what scientists now believe could be spotted by the James Webb Space Telescope.
A detectable glow
The MIT workshop examined theoretical models suggesting that a fully efficient Dyson sphere built around a black hole with ten times the mass of our Sun could radiate at a luminosity thousands of times that of a star. That kind of energy output would make it detectable by Webb’s Mid-Infrared Instrument, or MIRI, from up to a kiloparsec away — roughly 3,260 light-years. For perspective, the nearest known black hole to Earth is only about 1,500 light-years distant.
A Dyson sphere around a black hole that close could already be shining in the infrared, unnoticed because nobody had thought to look. The researchers at the workshop are betting that a systematic search of MIRI’s data archives could reveal such a signature.
The idea represents a major leap in thinking about advanced energy infrastructure. A star’s energy, while enormous, is diffuse. A black hole’s energy, concentrated by gravity and spin, could be gathered on a scale that dwarfs even the most ambitious solar-system-sized projects.
And while the Penrose process works only with rotating black holes, nearly all black holes in the universe are expected to spin. None of this technology exists today.
Building a Dyson sphere around a black hole remains far beyond current human capabilities. But the fact that the theoretical models now point to an observable signature in existing telescope data means that the search for such megastructures is no longer purely speculative. It is a practical investigation.
Penrose received the Nobel Prize in 2020 for his broader work on black holes, which included the 1969 paper describing this energy-extraction mechanism. Hawking’s 1974 prediction of radiation from black holes added another potential energy source. The workshop at MIT wove these threads together into a coherent observational strategy.
For the researchers involved, the challenge is twofold: confirm that the Penrose process could sustain a megastructure at the required efficiency, and then train the most sensitive infrared instrument ever built on the most promising candidates. The human side of this story is not about immediate applications — no one is proposing to power a city with a black hole anytime soon — but about the audacity of asking what might be possible when a civilisation matures enough to reach for the most extreme objects in the universe.
The next step will be to identify candidate black holes in the Milky Way that lie within a kiloparsec and have the right spin and mass. A handful of those already have known accretion disks that could be feeding a Dyson sphere. If the infrared glow is there, MIRI will see it.
