Stephen Hawking was right about black holes, but a new study has revealed an even more startling discovery
Research on black holes has served as a reminder of the way physicists think the universe will end: not with a bang, but rather with a fade away.
New research on black holes changes a 50-year-old idea
Black holes are not objects doomed to grow indefinitely by absorbing matter: they can also shrink. The reason for this is that they emit energy in the form of radiation, called Hawking radiation – a phenomenon named after its creator: Stephen Hawking. And as can be deduced from the most famous equivalence in physics, this results in a loss of mass. Recently, research conducted by experts from Radboud University in Nijmegen, Netherlands, has expanded this phenomenon beyond black holes…
Hawking radiation is one of the most amazing phenomena in the universe. Not only because of its implication in slimming down the greediest objects in our universe, but also because it combines the knowledge of quantum field theory with that of gravitational theory. Under normal conditions, particles and antiparticles can appear “out of nowhere”. These events last infinitesimal fractions of time during which the particle and antiparticle annihilate. But there is a context in which this does not happen: around the event horizon of a black hole.
In this case, particle and antiparticle can end up on opposite paths, unable to annihilate. This generates radiation that escapes from the black hole, which in turn implies a loss of mass from the black hole.
Stephen Hawking laid the foundations for something much greater
The latest research, published in the journal Physical Review Letters, questions the idea that only the presence of an event horizon is capable of generating enough curvature in spacetime to prevent the annihilation of particles and antiparticles. This in turn implies that this particular radiative fadeaway can occur in objects that, despite their significant masses capable of bending spacetime, do not have an event horizon since the gravitational attraction they generate is not of a nature to absorb light. Thus, even stars that are not massive enough to form a black hole at the end of their lives could gradually disappear.
New theoretical research by Michael Wondrak, Walter van Suijlekom and Heino Falcke of Radboud University has shown that Stephen Hawking was right about black holes, although not completely. https://t.co/OxdN4FhrwI @ncgnl @hfalcke @radboudscience
— Radboud University @Radboud_uni@mastodon.social (@Radboud_Uni) June 2, 2023
“We show that well beyond a black hole, the curvature of spacetime plays an important role in the creation of radiation. The particles are already separated by the tidal forces of the gravitational field,” explained Walter van Suijlekom, one of the authors of the research. It could therefore be said that Stephen Hawking, even though he was right in his postulate about the disappearance of black holes, could have failed – or succeeded, depending on how you look at it – by basing his analysis on the existence of singularities associated with black holes.
No one knows for sure what the end of the universe will look like, but astrophysicists have a well-established hypothesis (and several less consensual alternatives). And the idea of a universe on the verge of disappearing precisely matches the most widespread hypothesis.