Newswise — Recent theoretical research conducted by Michael Wondrak, Walter van Suijlekom, and Heino Falcke from Radboud University has confirmed Stephen Hawking's assertion regarding black holes, albeit with some nuances. The study reveals that black holes do undergo evaporation over time due to Hawking radiation, but it challenges the previously held belief that the event horizon is the decisive factor. Gravity and the curvature of spacetime also contribute to this radiation. Consequently, all substantial entities in the cosmos, such as stellar remnants, will eventually experience evaporation.

Stephen Hawking utilized a brilliant fusion of quantum physics and Einstein's theory of gravity to present his argument that the event horizon, the boundary beyond which gravitational forces prevent escape from a black hole, is a site where the spontaneous formation and annihilation of particle pairs takes place. These pairs, consisting of a particle and its antiparticle, briefly emerge from the quantum field before annihilating each other. However, occasionally, one of the particles plunges into the black hole while the other manages to escape. This phenomenon, known as Hawking radiation, would eventually lead to the gradual evaporation of black holes, as postulated by Hawking.


In this recent research conducted at Radboud University, scientists delved into the process described above and reexamined the significance of the event horizon. Employing a combination of methodologies from physics, astronomy, and mathematics, they explored the consequences of particle pairs being generated in the vicinity of black holes. The study unveiled a remarkable finding: particles can be created at distances well beyond the traditional notion of the event horizon. Michael Wondrak, one of the researchers involved, remarked, "Our findings demonstrate the existence of a previously unrecognized form of radiation alongside the well-known Hawking radiation."

Everything evaporates

Van Suijlekom elaborates on the research findings, stating, "We have revealed that the curvature of spacetime significantly contributes to the generation of radiation, even at far distances from a black hole. The tidal forces of the gravitational field already cause separation between the particles in those regions." The previous belief that radiation could only occur within the confines of the event horizon has been challenged by this study, demonstrating that the presence of the event horizon is not a prerequisite for radiation to occur.

Falcke emphasizes the implications of the study, stating, "Consequently, entities in the universe lacking an event horizon, such as remnants of deceased stars and other sizable objects, exhibit this radiation phenomenon as well. Over an extensive timeframe, this process would lead to the eventual evaporation of everything in the universe, akin to black holes. This revelation not only alters our comprehension of Hawking radiation but also reshapes our perspective on the universe and its future."

 The study was published on 2 June in the leading journal “Physical Review Letters” of the American Physical Society (APS).  Michael Wondrak is excellence fellow at Radboud University and an expert in quantum field theory. Walter van Suijlekom is a Professor of Mathematics at Radboud University and works on the mathematical formulation of physics problems. Heino Falcke is an award-winning Professor of Radio Astronomy and Astroparticle Physics at Radboud University and known for his work on predicting and making the first picture of a black hole.

Journal Link: Physical Review