Experiment proves old theory of how aliens might use black holes for energy

Researchers create a device to test a 50-year-old physics theory from the famed Roger Penrose.

Cygnus X-1 black hole

Cygnus X-1 black hole.

Credit: NASA/CXC/M.Weiss
  • Scientists prove a 50-year-old physics theory by Roger Penrose.
  • The theory explains how energy could be harvested from black holes by advanced aliens.
  • Researchers from the University of Glasgow twisted sound waves to show that the effect Penrose described is real.

A theory proposed 50 years ago to explain how energy might be harvested from a black hole was verified by an experiment. Scientists from the University of Glasgow were able to provide first proof for an idea from 1969 by the famed British physicist Roger Penrose, who predicted that only an advanced alien civilization would be able to get energy in the black hole's ergosphere – the outer layer of its event horizon.

Why would it take aliens to do this? Penrose thought that if you lower an object into the ergosphere, you could produce negative energy. But for this to work, the object would have to be moving faster than the speed of light. Penrose envisioned a mechanism that would split an object dropped into the black hole in two, with one part going into the hole while the other would be recovered. As explains the press release from the University of Glasgow, the recoil generated by this process would result in the saved half gaining energy from the black hole's rotation.

Of course if this sounds complicated, it really is and only a very high-tech futuristic civilization would be up for the challenge, concluded Penrose.

What the scientists were able to do now was to test this idea by an experiment based on the proposal from another physicist, Yakov Zel'dovich. He suggested in 1971 that Penrose's theory could be proven by using "twisted" light waves, which would create energy by hitting a rotating metal cylinder and utilizing the rotational Doppler effect.

While Zel'dovich's approach also proved impractical, the scientists from the Glasgow University's School of Physics and Astronomy devised a setup of a small ring of speakers that twisted sound waves in a way similar to how he wanted to twist light. The advantage is that sound waves need a significantly slower rotating surface compared to light.

Check out how the researchers explain their work

The team sent twisted sound waves towards a rotating sound absorber from a foam disk. Microphones positioned in the back of the disk captured the sound that passed from the speakers through the disc, which spun faster and faster.

What the scientists found was that this process produced clear changes in the frequency and amplitude of the sound waves, courtesy of the unusual behavior of the Doppler effect, which normally describes how for example, the pitch of a siren from an emergency vehicle seems to rise as it heads towards you but drops when it moves away. This happens because sound waves come at you with more frequency when the ambulance closes in, but less so after it goes past.

The paper's lead author, Marion Cromb, a Ph.D. student in the University's School of Physics and Astronomy, explained that rotation transforms this linear effect and pulls in energy. "The rotational doppler effect is similar, but the effect is confined to a circular space," he pointed out. "The twisted sound waves change their pitch when measured from the point of view of the rotating surface. If the surface rotates fast enough then the sound frequency can do something very strange—it can go from a positive frequency to a negative one, and in doing so steal some energy from the rotation of the surface."

The set-up of the experiment.

Credit: University of Glasgow

The researchers were able to show that as they increased the speed of the spinning disc, the pitch of the sound kept dropping until it disappeared, then it came back up to 30 percent louder than before.

Marion called what they heard during the experiment "extraordinary," adding that the "negative-frequency waves are capable of taking some of the energy from the spinning foam disc, becoming louder in the process—just as Zel'dovich proposed in 1971."

Whether aliens are using this approach to get energy from black holes is certainly hard to ascertain, but the researchers are planning to investigate whether this effect extends to other sources like electromagnetic waves.

Check out their new paper "Amplification of waves from a rotating body" in Nature Physics.


How tiny bioelectronic implants may someday replace pharmaceutical drugs

Scientists are using bioelectronic medicine to treat inflammatory diseases, an approach that capitalizes on the ancient "hardwiring" of the nervous system.

Left: The vagus nerve, the body's longest cranial nerve. Right: Vagus nerve stimulation implant by SetPoint Medical.

Credit: Adobe Stock / SetPoint Medical
Sponsored by Northwell Health
  • Bioelectronic medicine is an emerging field that focuses on manipulating the nervous system to treat diseases.
  • Clinical studies show that using electronic devices to stimulate the vagus nerve is effective at treating inflammatory diseases like rheumatoid arthritis.
  • Although it's not yet approved by the US Food and Drug Administration, vagus nerve stimulation may also prove effective at treating other diseases like cancer, diabetes and depression.
Keep reading Show less

"Forced empathy" is a powerful negotiation tool. Here's how to do it.

Master negotiator Chris Voss breaks down how to get what you want during negotiations.

Credit: Paul Craft / Shutterstock
Personal Growth
  • Former FBI negotiator Chris Voss explains how forced empathy is a powerful negotiating tactic.
  • The key is starting a sentence with "What" or "How," causing the other person to look at the situation through your eyes.
  • What appears to signal weakness is turned into a strength when using this tactic.
Keep reading Show less

Toward a disease-sniffing device that rivals a dog’s nose

Trained dogs can detect cancer and other diseases by smell. Could a device do the same?

JOEL SAGET/AFP via Getty Images
Technology & Innovation

Numerous studies have shown that trained dogs can detect many kinds of disease — including lung, breast, ovarian, bladder, and prostate cancers, and possibly Covid-19 — simply through smell. In some cases, involving prostate cancer for example, the dogs had a 99 percent success rate in detecting the disease by sniffing patients' urine samples.

Keep reading Show less

Scientists are building Earth’s virtual twin

Their goal is a digital model of the Earth that depicts climate change in all of its complexity.

Credit: Theis/Adobe Stock
Technology & Innovation
  • The European Union envisions an ambitious digital twin of the Earth to simulate climate change.
  • The project is a unique collaboration between Earth science and computer experts.
  • The digital twin will allow policymakers to audition expansive geoengineering projects meant to address climate change.
Keep reading Show less
Surprising Science

New research shows that bullies are often friends

Remedies must honor the complex social dynamics of adolescence.

Quantcast