Black holes are among the most mysterious objects in the universe, capable of warping the fabric of space around them so much that even light cannot escape their gravitational grip. But it turns out that much of what scientists know about these mysterious objects may be wrong.
According to a new study published in April in the journal Physical examination Dblack holes may actually be completely different celestial entities known as gravitational stars.
“Gravastars are hypothetical astronomical objects that have been presented [in 2001] as an alternative to black holes,” study co-author Juan Luis Rosa, a physics professor at the University of Gdańsk in Poland, told Live Science 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 using gravity stars
Carl Schwarzschild, a German physicist and astronomer, first predicted black holes in 1915, based on calculations using Albert Einstein. of the general theory of relativity.
Over the years, astronomical observations have seemingly confirmed the existence of objects similar to black holes. However, Schwarzschild’s description of these cosmic bodies has some flaws.
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, but the fundamental physics teaches us that infinities do not exist, and their appearance in any theory signals its inaccuracy or incompleteness.
“These problems indicate that there is something wrong or incomplete with the black hole model, and that alternative models need to be developed,” Rosa said. “Gravastar is one of many alternative models offered. The main advantage of gravastar is that they have no special features.”
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Like ordinary black holes, gravitational stars must arise at the final stage of the evolution of massive stars, when the energy released by the thermonuclear combustion of matter inside them is no longer enough to overcome the force of gravity, and the star collapses into a much denser object. But unlike black holes, gravitational stars should not have any singularities and are considered thin spheres of matter whose stability is maintained by the dark energy contained within them.
To find out whether gravitational stars are a viable alternative to single black holes, Rosa and his colleagues studied the interactions of particles and radiation with these hypothetical objects.
Using EinsteinIn theory, the authors explored how the huge masses of hot matter surrounding supermassive black holes would have formed if those black holes were actually gravistars. They also carefully studied the properties of “hot spots” — giant gas bubbles that rotate around black holes at near-light speeds.
Their findings revealed a striking similarity between the matter emissions of superstars and black holes, which suggests that superstars do not contradict the experimental observations of scientists of the universe. What’s more, the team found that the gravitational star itself should look almost like a single black hole, creating a visible shadow.
“This shadow is not caused by the capture of light in the event horizon, but by a slightly different phenomenon called ‘gravitational redshift,’ in which light loses energy as it moves through a region with a strong gravitational field,” Rosa said. “Indeed, when light emitted from regions close to these alternative objects reaches[es] our telescopes, most of its energy would be lost to the gravitational field, causing this shadow to appear.”
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The striking similarity between the Schwarzschild black hole model and gravitational stars highlights the potential of the latter as a realistic alternative free from the theoretical pitfalls of the singularity.
However, this theory must be supported by experiments and observations, which, according to the authors of the study, may soon be conducted. While supermassive stars and single black holes may behave the same in many ways, subtle differences in the light they emit can potentially set them apart.
“For experimental verification of our results, we look to the next generation of observational experiments in gravitational physics,” Rosa said, referring to the search for black holes. Event Horizon Telescope and GRAVITY+ the instrument is attached to the Very Large Telescope in Chile. “These two experiments aim to closely observe what is happening near the center of galaxies, in particular our own The Milky Way.”