To non-physicists, the terms “fuzzball” and “wormhole” seem like made-up words. Maybe some people have heard of wormholes due to their prevalence in science fiction movies like Interstellar (2014) or Contact (1997), but the term “fuzzball” was new to this author. However, to physicists, these words make up one of the greatest questions of black holes ever posed.
The fuzzball versus wormhole paradox was a problem created by Stephen Hawking, who concluded that data that enters a black hole could never leave. This is due to a black hole’s event horizon, a point of no return for anything that travels beyond it. The material trapped inside the black hole is either sucked into the center, creating a wormhole, or squeezed into strings, making something analogous to a fuzzball that fills up inside of the black hole.
A new study published in the Turkish Journal of Physics proposed an end to this debate: black holes contain fuzzballs, not wormholes. The research was led by Samir Mathur, a physics professor at The Ohio State University. Mathur also published a paper in 2004 based on the string theory, which proposes that all particles are made of tiny, vibrating strings. In this paper, Mathur and his colleagues argued that data entering a black hole is not lost but instead is compressed into its base elements of strings. Based on the equations Mathur and his team derived, the strings are messy, tangling to form the giant fuzzball.
Following the 2004 study, many in the physics community believed the problem had been solved, but not all of them. “They were bothered that, in physical terms, the whole structure of the black hole had changed,” Mathur said. Instead, these physicists proposed the wormhole theory, wherein anything that enters a black hole is transported to another space and time through a bridge of some sorts, known as a wormhole.
Mathur’s publication and accompanying essay (published in the International Journal of Modern Physics) disproves the wormhole theory by proving a different one known as the “effective small corrections theorem.” If the wormholes existed, some radiation would leak from the black hole at its event horizon. The effective small corrections theorem demonstrates that if black holes were to radiate energy this way, it would not be consistent “with the requirement that the black hole radiate like a piece of coal as seen from outside,” the essay explains. The coal metaphor has been used to help visualize black hole radiation, imagining that it glows like hot coal.
Essentially, the physics of the wormhole model was not inconsistent. Mathur explains: “The wormhole paradigm tries to argue that, in some way, you could still think of the black hole as being effectively empty with all the mass in the center. And the theorems we prove show that such a picture of the hole is not a possibility.”
At the end of the day, this study does not put a definitive end to the debate. For one, some in the physics community aren’t entirely convinced that string theory is the correct way to explain the fundamentals of particles. Instead, this study provides another data point in the great fuzzball versus wormhole debate and gives us a brief insight into the giant mysteries of black holes.
Source: Ohio State University, Turkish Journal of Physics, International Journal of Modern Physics, Scientific American