Pallab Ghosh is a science correspondent.

Black holeImage source, EHT
Image caption, Black holes form when massive stars run out of fuel and implode

One of the biggest paradoxes in science was solved by scientists.

Black holes behave in a way that puts two theories at odds.

Light can't escape from black holes that are dead stars.

New research claims to have solved the paradoxes by showing that black holes have a property called quantum hair.

The problem has been solved, according to Prof Xavier Calmet of the University of Sussex. He was one of the people who developed the mathematical techniques.

Two of the most important theories in physics have been threatened by a problem at the heart of the paradoxes. Information about what goes into a black hole cannot come out, according to Einstein's general theory of relativity.

According to Prof Calmet and his colleagues, they have shown that the black hole has an impact on the star's constituents.

The scientists named their theory the "quantum hair" because of the earlier idea that was developed by Prof John Archibald Wheeler.

Stephen HawkingImage source, BBC/Richard Ansett
Image caption, Prof Stephen Hawking came up with a paradox in the 1970s that suggested either the theory of general relativity or quantum mechanics isn't quite right.

Prof Wheeler came up with the name because it conveys the mathematical description of a black hole: an entity which has mass, spin and charge but is otherwise has no other physical features.

Prof Calmet's hair theorem was published in the journal Physical Review Letters. It claims to be able to resolve the Hawking paradox, a problem that physicists have been troubled by since Prof Hawking came up with it in the 1970s.

Most of our understanding of the Universe rests on the twin pillars of quantum mechanics and general relativity, which is why the possibility that either might be flawed is frightening for theoretical physicists.

M87Image source, DR JEAN LORRE/SCIENCE PHOTO LIBRARY
Image caption, This false colour image suggests that galaxies have a black hole at their centre. But what happens to the material that is sucked into them?

The hair theorem claims to resolve the paradoxes by closing the gap between quantum mechanics and general relativity. Information about what goes into a black hole can come out again without violating any of the important principles of either theory. It is a simple solution.

Prof Calmet says it will take some time for people to accept it.

It is a big deal in the world of theoretical physics.

Prof Calmet says thatHawking came up with the paradoxes in the year that I was born.

Many famous physicists around the world have been working on it since then, and some of them have suggested that some aspects of quantum mechanics are incorrect.

Prof Calmet said it will take a while for people to accept that you don't need a radical solution to crack the issue.

He said it could be the first step in connecting the theories of relativity, which concern gravity and quantum mechanics, which largely focus on the three other forces of nature, which are electromagnetism and two nuclear forces.

One of the consequences was that general relativity and quantum mechanics weren't compatible. They are very much compatible.

The research team, which also includes Prof Roberto Casadio of the University of Bologna and Prof Stephen Hsu from Michigan State University, was built on the work of Prof Suvrat Raju of the International Centre for Theoretical Sciences in India. Prof Raju believes that they have solved the problem.

He said that in the past few years, it has been recognized that the no hair theorem fails due to quantum effects.

  • Physics
  • Black holes
  • Stephen Hawking