Scientists from Goethe University, Frankfurt, studying alternatives to black holes have suggested a mathematically viable formation mechanism for one proposed alternative called a ‘Gravastar.’
Although the team behind the newly proposed gravastar formation mechanism conceded that black holes still represent the simplest and most natural solution to gravitational collapse, they also suggest that the physics behind the alternative, which doesn’t require a single point where spacetime curves infinitely, called a “singularity,” can make them “easier to accept” than black holes.
If correct, and some or all black holes are, in fact, gravastars that mimic their expected properties, the work would establish a valid formation mechanism that could rewrite decades of accepted science and open a new field of research dedicated to understanding this previously misunderstood phenomenon.
Meet Gravastar: The Black Hole Mimicker without a Singularity
According to standard cosmology theories, black holes form when extremely massive stars stop generating energy, allowing the force of gravity to take over and collapse the remaining matter into a single point, or singularity. Unfortunately, the research team behind the new study notes that “the laws of physics break down” within the singularity, making the formation of the resulting black hole a difficult phenomenon to predict.
“How can spacetime be curved infinitely at that point, the singularity?” asks the team’s statement announcing the new approach. They also note that no information escapes a black hole, including light, making studying its inner workings effectively impossible, and opening up the possibility that “black holes are in fact entirely different objects.”
Some options have been proposed, including ‘horizonless’ black hole mimickers. The team notes that these proposed options are “mathematically consistent alternatives” that also address the physics challenges posed by traditional black holes.
Still, how these alternative objects form has remained largely unclear. The research team said this lack of a formation mechanism constitutes “a significant open problem” since understanding how they form is the “first step” to determining if they truly exist.
New Model Creates a ‘Big Bang’ Inside a ‘Mini-Universe’
In the new formation model, theoretical physicists Daniel Jampolski and Theoretical Astrophysics Professor Luciano Rezzolla from Goethe University showed that the collapse of a dying star may not go far enough that it reaches the point of no return, where “the collapse to a black hole is inevitable.”
Instead, the collapse slows down near a point scientists call the Schwarzschild radius, then stops. The result is what the team termed a “miniature universe” within the collapsing matter, which they compared to the dynamics of the Big Bang, which most theorists agree formed the entire universe.
Since the universe’s expansion was driven by dark energy, the new model proposes that the dark energy within the mini-universe establishes an “equilibrium” with the counteracting force of gravity, therefore halting the collapse of the star “before a black hole can form.”
“The Big Bang of the emerging universe can unfold once the star has already collapsed almost to the point of becoming a black hole,” explained Jampolski, who discovered the black hole alternative gravastar solution in his master’s thesis while under the supervision of Professor Rezzolla.
Maintaining an Unbiased Approach Toward “What We Do Not Know”
When discussing the impact of their proposed black hole alternative formation model, Jampolski said that from a mathematical and physics standpoint, it is “easier to imagine that the Big Bang occurs only at a very late stage, when matter has already been compressed to an extreme degree, thereby giving rise to new effects.” The team also notes that the unresolved behavior of matter in this environment “leaves room for new physics.”
Although the team’s model offers a mathematically sound formation for an alternative to black holes, Rezzolla notes that the search for gravastars or other alternatives “should not suggest a skepticism towards black holes,” which, he adds, “still represent the most natural and simplest solution to the fate of gravitational collapse.”
Instead, the Goethe professor explained, his general role as a scientist and his specific discipline as a theoretical physicist make it essential that he and his colleagues “maintain an unbiased approach towards what we do not know and hence explore both the accepted wisdom and the more exotic interpretations.”
“History teaches us that it is not unusual for the latter to become the former,” the professor added.
The paper “Formation of gravastars” was published in the journal Physical Review D.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.