Hawking radiation theory solved after black hole made of sound waves created

A scientist has created a black hole made of sound waves that has probably proved the Hawking Radiation theory – if this is confirmed and replicated by other physicists, Prof. Stephen Hawking may finally be awarded the Nobel Prize.

For decades, while Hawking radiation may have solved the black hole information paradox, in theory, nobody has ever been able to directly detect it, that is, until now in a simulation.

Scientists once said that, according to the laws of physics, the volume and entropy of a black hole could never be reduced. Then Mexico-born Israeli-American theoretical physicist Jacob David Bekenstein proved that, according to the ‘weird’ laws of quantum mechanics, the volume of a black hole gradually declines until it vanishes altogether.

Hawking RadiationHawking Radiation is named after Prof. Stephen Hawking, who provided a theoretical argument for its existence in 1974 and sometimes also after Prof. Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy. (Image: physicsoftheuniverse.com)

Hawking radiation

In 1974, eminent theoretical physicist and cosmologist Professor Stephen Hawking showed that black holes should emit electromagnetic radiation with a black body process – this process is called Hawking Radiation or Black Hole Evaporation.

How does this theoretical process work? Particle-antiparticle pairs are continuously being produced and rapidly disappear through annihilation (a particle annihilates an antiparticle). These particle-antiparticle pairs are virtual pairs, and their existence is a certain consequence of the Uncertainty Principle. We know of the existence of the particle and antiparticle of these pairs, but have never seen them in real life.



If one particle-antiparticle pair pops into existence close to the *event horizon of a black hole, one could fall into the black hole while the other escapes, and the black hole consequently loses mass. Far away from the event horizon, this looks just like black body radiation.

* The event horizon is the (notional) boundary around a black hole beyond which no light or other radiation can escape.

Prof Jeff SteinhauerProf. Jeff Steinhauer (above) said: “We recently made the first observation of thermal, quantum Hawking radiation in any system.  This was the result of a 5-year effort, in which we created a sonic black hole, and developed the techniques required to carefully study minute distributions of phonons in a Bose-Einstein condensate.” (Image: phsites.technion.ac.il)

Hawking radiation theory – 42 years no practical proof

However, after forty-two years, no scientist has been able to prove the Hawking radiation theory, mainly because the light particles emitted from black holes are too small and contain too little energy to detect from Earth.

Prof. Jeff Steinhauer, from the Physics Department at Technion University in Israel, thought that a solution might be to bring the black hole to Earth, so to speak. He simulated a lab-sized black hole using sound waves.



In a paper published in ArXiv (citation below), a repository of electronic pre-prints (e-prints) of scientific papers, Prof. Steinhauer explains how he simulated a black hole event horizon by cooling helium to marginally above absolute zero (–273.15°C), and then heating it extremely rapidly so that it would form a barrier through which sound would not be able to escape – a scenario similar to light being trapped by a black hole.

If Prof. Hawking’s calculations were right, then we could predict that tiny units of sound would escape through the barrier, in the same way tiny photons are theorised to escape from black holes.

Lo and behold, Prof. Steinhauer said he detected acoustic photons – tiny collections of energy that sound is made of – escaping from the simulated black hole.

Prof. Steinhauer points out that his experiment has only recently been published in a pre-print repository and has not yet been peer reviewed. However, physicists across the world are already describing the results as a groundbreaking and controversial breakthrough.

Stephen Hawking and elusive Nobel PrizeProfessor Stephen Hawking, probably the most famous and well respected physicist alive today, has won virtually every prize and fellowship available – except for the Nobel Prize. Could Prof. Steinhauer’s research bring him one step closer to the elusive prize? (Images: hawking.org.uk and airandspace.si.edu)

Does this mean the Nobel Prize for Prof. Hawking?

It is now looking increasingly likely that Prof. Hawking’s long-standing theory is true. If Prof. Steinhauer’s findings are verified and replicated by other physicists, Prof. Hawking should be getting ready for the trip to Scandinavia to receive that elusive Nobel Prize.

In an interview with The Times, physicist Silke Weinfurtner, a Royal Society University Research Fellow and Nottingham Research Fellow, said:

“The experiments are beautiful,” physicist Silke Weinfurtner from the University of Nottingham, who is running similar experiments to prove or disprove Hawking radiation. Jeff has done an amazing job, but some of the claims he makes are open to debate. This is worth discussing.”

At the end of the Paper, Prof. Steinhauer wrote:

“In conclusion, thermal Hawking radiation stimulated by quantum vacuum fluctuations has been observed in a quantum simulator of a black hole. This confirms the prediction of Hawking regarding spontaneous pair production in the presence of a horizon.”

“This has implications beyond the physics of black holes, as it confirms the semi-classical step toward the understanding of quantum gravity.”

Collins English Dictionary describes Hawking Radiation as follows:

“The emission of particles by a black hole. Pairs of virtual particles in the intense gravitational field around a black hole may live long enough for one to move outward when the other is pulled into the black hole, making it appear that the black hole is emitting radiation.”

Citation:Observation of thermal Hawking radiation and its entanglement in an analogue black hole,” Jeff Steinhauer, Department of Physics, Technion—Israel Institute of Technology, Technion City, Haifa 32000. Israel. arXiv:1510.00621 .

Video – Black Holes & Hawking Radiation

In this video, actor Morgan Freeman explains Black Holes and Hawking Radiation.