The imagination of physicists knows few limits. About twenty years ago, it gave birth to the interesting concept of Gravastar. Today, she is once again pushing the boundaries of reality by introducing the idea of stars nested within each other. Much like Russian dolls!
It's a very cool theory. As a kind of alternative to describing black holes. It was introduced in 2001 by two PhysicistsPhysicists Americans Emil Mottola and Paul Mazur. This is the so-called gravastar theory, which is a portmanteau of “gravitational vacuum star”. Before going further, it is interesting to note that it is far from a consensus within the scientific community.
Nevertheless, let's see how the two physicists imagine “gravitational vacuum stars”. Well, like a compact object like a black hole that has the same amount of surface gravity. But like an object, it also represents neither an event horizon—that is, no boundary within which no information can be transmitted—nor a fundamental singularity.
Gravastar as an alternative to black holes
This deserves some clarification. It was the German physicist Karl Schwarzschild who proposed a solution to Albert Einstein's equations according to which the center of a black hole consists of a single unit. Understand, from the point where space and time no longer exist. Where laws physicalphysical No longer applies. So no information can escape from the black hole outside what scientists call the event horizon.
The Gravastars of Mottola and Mazur are slightly different. Their heart would be composed of strange energy that would be exerted pressurepressure Negative on the massive gravitational forcegravitational force Which compresses the star. Its surface will be reduced to a solidsolid leather ThemeTheme More ordinary. Solid but thin, researchers estimate that its thickness is close to zero.
Gravastars are nested like Russian dolls
More than 20 years after the first mention of gravastars, physicists from Goethe University (Germany), Daniel Jampolski and Luciano Rizzola, are still proposing an alternative. A completely speculative alternative, but they present it in a very serious review Classical quantum gravity. Their solution turned out to be crazier than their colleagues'. It describes the existence of gravastars inside other gravastars. Like Russian dolls, the famous matryoshka. Researchers have even found a name for these amazing objects. They qualify for them “Lovers”a word taken from the English language “crossed” Means “crossed”. According to them, their shell would be easier to visualize, as it is slightly thicker than gravstar shells.
“It is remarkable that even 100 years after Schwarzschild presented his first solution to the equationsEinsteinEinstein Through the theory of general relativity, new solutions can still be found. It's a bit like finding a gold coin on a path that has already been explored by many others. Unfortunately, we still do not know how such a gravastar could be created. But even if stars don't exist, exploring the mathematical properties of these solutions will ultimately help us understand black holes better.says Luciano Rizzola, professorAstrophysicsAstrophysics Theory, in A Press release from Goethe Universityto explain his enthusiasm about this topic.
