Black holes are among the most mysterious objects in the universe, capable of warping the fabric of space around them so violently that not even light can escape their gravity. But it turns out that much of what scientists know about these mysterious objects may be wrong.
This is evident from new research published in the journal in April Physical examination Dblack holes could actually be entirely different celestial entities known as gravastars.
“Gravastars are hypothetical astronomical objects that have been introduced [in 2001] as alternatives to black holes,” studies co-author João Luis Rosa, a professor of physics at the University of Gdańsk in Poland, told LiveScience in an email. “They can be interpreted as stars made of vacuum energy or dark energy: the same type of energy that drives the accelerated expansion of the universe.”
Solving black hole paradoxes with gravastars
Karl Schwarzschild, a German physicist and astronomer, first predicted black holes in 1915, based on calculations using Albert Einstein’s calculations. general relativity.
Over the years, astronomical observations have seemingly confirmed the existence of objects that resemble black holes. However, Schwarzschild’s description of these space bodies has some shortcomings.
In particular, the center of a black hole is predicted to be a point of infinitely high density, called a singularity, where all of the black hole’s mass is concentrated. physics teaches us that infinities do not exist, and that their appearance in any theory indicates its inaccuracy or incompleteness.
“These problems indicate that something is wrong or incomplete in the black hole model, and that the development of alternative models is necessary,” Rosa said. “The gravastar is one of several proposed alternative models. The main advantage of gravastars is that they have no singularities.”
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Like regular black holes, grav stars should form at the final stage of the evolution of massive stars, when the energy released during the thermonuclear combustion of the matter inside is no longer sufficient to overcome gravity, and the star collapses into a much denser mass. object. But unlike black holes, gravastars are not expected to have any singularity and are considered thin spheres of matter whose stability is maintained by the dark energy they contain.
To find out whether gravastars are viable alternatives to single black holes, Rosa and his colleagues examined the interactions of particles and radiation with these hypothetical objects.
Using EinsteinIn their theory, the authors explored what the enormous masses of hot matter surrounding supermassive black holes would look like if these black holes were actually gravastars. They also investigated the properties of “hot spots” — gigantic gas bubbles orbiting black holes at near-light speeds.
Their findings revealed striking similarities between the matter emissions from gravastars and black holes, suggesting that gravastars do not contradict scientists’ experimental observations of the universe. Furthermore, the team found that a gravastar itself should almost resemble a single black hole, creating a visible shadow.
“This shadow is not caused by the trapping of light in the event horizon, but by a slightly different phenomenon called ‘gravitational redshift,’ which causes light to lose energy as it moves through an area with a strong gravitational field,” Rosa said. “Indeed, when the light emitted from areas close to these alternative objects reaches[es] Our telescopes would have lost most of its energy to the gravitational field, creating this shadow.”
The striking similarities between Schwarzschild’s black hole model and gravastars highlight the latter’s potential as a realistic alternative, free from the theoretical pitfalls of singularities.
However, this theory needs to be supported with experiments and observations, which the study authors believe could be conducted soon. Although grave stars and single black holes may behave similarly in many ways, subtle differences in the light emitted can potentially distinguish them.
“To test our results experimentally, we rely on the next generation of observational experiments in gravitational physics,” Rosa said, referring to the hunt for black holes. Event Horizon telescope and the GRAVITY+ instrument being added to the Very Large Telescope in Chile. ‘These two experiments aim to accurately observe what happens near the centers of galaxies, in particular ours Milky Way.”