Humans Could Use Black Holes as Batteries, Physicists Claim

In a recent study, scientists proposed two potential ways to use energy from black holes. They’ve discovered methods to draw out energy from black holes by utilizing their spinning and gravitational characteristics.

Lead researcher Zhan Feng Mai, a postdoctoral scientist at the Kavli Institute for Astronomy and Astrophysics at Peking University, said, “We know that we can extract energies from black holes, and we also know that we can inject energy into them, which almost sounds like a battery.”

Charge black hole with electrically charged particles

One possible hypothetical situation is that scientists would “charge” the black hole by shooting in huge, electrically-charged particles.

This would keep going until the black hole developed its own electric field, pushing away any more charges they tried to add. The researchers detailed this in a study published on November 29th in the journal Physical Review D.

Once the force pushing charges away became stronger than the black hole’s gravitational pull, scientists would label it as “fully charged.”

In relation to Einstein’s theory of general relativity, which links mass to energy, the black hole’s energy would result from both the electrical charges added to it and the mass of those charges.

“The black hole battery is transforming the energy of the particle’s mass into charge energy,” said Zhan Feng Mai.

The scientists worked out that the recharging process is about 25 percent efficient. This means black hole batteries could turn roughly a quarter of the mass they take into usable energy in the shape of an electric field. The team found this efficiency would be around 250 times greater than that of an atomic bomb, as reported by Live Science.

Extracting energy using the ‘superradiance’ process

To extract the energy, scientists would use a method called superradiance. This idea is based on the concept that the intense gravitational field of a spinning black hole drags space-time around it.

Gravitational or electromagnetic waves entering this rotating area would also get pulled along. If these waves hadn’t crossed the black hole’s event horizon yet (the point of no return for anything, even light), some waves might bounce off with more energy than they had initially.

The researchers explained that this process turns the black hole’s rotational energy, linked to its mass, into the deflected waves, according to Live Science.

Extracting black hole energy using ‘Schwinger pairs’

The second way to tap into black hole energy involves extracting it as what scientists call Schwinger pairs—pairs of particles that spontaneously form when there’s an electric field.

Imagine we have a fully charged black hole. The electric field near its event horizon could be so powerful that it spontaneously produces an electron and a positron, which is like an electron but with an opposite charge, as Mai clarified.

If the black hole is positively charged, the repulsion would propel the positron out from the black hole. In theory, we could then capture that escaping particle as energy.

Mai mentioned he’s unsure if we’ll ever actually have a battery like this, but the idea came from scientists’ past efforts to determine how we could, in theory, attain energy from black holes.