by A newly developed solution to the equations at the heart of the Albert EinsteinThe most revolutionary theory suggests that hypothetical stars called “nestars” could be made from stacked gravitational stars, or “gravastars,” like Russian tea dolls, also known as matryoshka dolls.
One of the most remarkable things about Einstein’s 1915 theory of gravity, general relativity, is the incredible amount of cosmic objects its central equations predict.
In addition to predicting that gravity arises from massive objects orbiting the fabric of space-time, general relativity spawned theories of black holes and the leaks they create in that fabric called gravitational waves. Both of these things were confirmed by observation; Other general relativity-based ideas that have remained, however, are anti-black holes known as white holes, and “pinholes” that could connect them to black holes. Only time will tell if Einstein can be marked right again on that front.
To that end, another theoretical idea that emerged from general relativity in 2001 is the concept of “gravastars,” or dense bodies with dark energy cores. Dark energy is the force that appears to be accelerating the expansion of the universe. In gravastars, scientists believe that dark energy would exert a negative pressure to protect the stars from their own gravitational forces.
And now, a new solution to general relativity reveals another interesting aspect of so-called gravastars. They could be stacked, one inside the other, to create a sequence of “nestars”.
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“The nestar is like a matryoshka doll; our solution to the field equations allows for a whole series of nested gravastars,” said one of the solution developers, Goethe University theoretical physicist Daniel Jampolski, in a statement.
Meet gravastars similar to black holes but different
Just a year after the general theory of relativity was released to the wider scientific community, and while serving on the front lines of the First World War, the German physicist Karl Schwarzschild developed the first solution to his field equations, which surprised even Einstein who believed that a solution would take place. years to develop.
Within Schwarzschild’s solution were two elements that would eliminate the concept of a black hole. The German physicist predicted that at a certain radius from a body with mass, the velocity required to escape from that body would have to increase to more than the speed of light.
For most bodies, this Schwarzschild radius would be deep below the surface; for the sun, for example, it would be located 1.9 miles (3 kilometers) from the center of our star, which has an overall radius of 434,000 miles (700,000 kilometers). But, if a star collapsed and its radius decayed below the Schwarzschild radius, the result would be a body with a head. out a limit that even light could not escape. This led to the concept of the black hole’s exit horizon.
Even more curiously, Schwarzschild’s solution suggested that there might be a point where matter is so dense that even the general equations of relativity must break down. This has been called the central singularity of a black hole, where all known physical theories make no sense.
These concepts were verified in 1971 when mankind discovered the first black hole, and later in the 2000s it was discovered that a strong radio source at the heart of the Milky Way is indeed a supermassive black hole with a mass 4.5 million times greater more than the sun. This huge void in our galaxy is called Sagittarius A* (Sgr A*.).
The visual form of black holes, as painted by general relativity, was also impressively confirmed in 2019 when the Event Horizon revealed to the public an image of a glowing ring of matter around the supermassive black hole at the heart of the galaxy Messier 87. Telescope collaboration.
Pawel Mazur and Emil Mottola theorized Gravastars, or “gravitational condensation stars,” in 2001 as an alternative to black holes.
From the perspective of theoretical physicists, gravastars have several advantages over black holes. They are almost as dense as black holes and have a gravitational influence on their surface that is essentially as strong as a black hole, so they have a strong resemblance. But, there are key differences. For one, gravastars do not have an event horizon and therefore do not seal light, and therefore information, behind a one-way “screen”. Second, there would be no singularity in the hearts of graavastars, which are instead thought to have dark energy hearts.
This recipe for gravastars cooked by Mazur and Mottola consists of a thin skin of an almost infinite amount of ordinary matter, which is difficult for scientists to explain. Nestars achieves this, suggesting that the “stacked” bit would result in a thicker shell of material.
“It’s a little easier to imagine that something like this could exist,” Jampolski said.
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Of course, however, just because the field equations of general relativity allow some object to exist in the cosmos does not mean that the object must exist.
“Unfortunately, we still have no idea how such a gravastar could be created,” nestar theory co-developer and Goethe University theoretical physicist Luciano Rezzolla said in the statement. “But even if there are no nests, exploring the mathematical properties of these solutions ultimately helps us better understand black holes.”
Research like this is also useful, even if the primary theory doesn’t come to an end, because it shows amazing ways that were born from a theory that was first observed more than a century ago.
“It is amazing that even 100 years after Schwarzschild presented his first solution to Einstein’s field equations from the general theory of relativity, he is still able to find new solutions,” said Rezzolla. “It’s a bit like finding a gold coin along a path that many others have explored before.”
This research was published on February 15 in the journal Classical and Quantum Gravity.
