Astronomers made these stunning observations using the European Southern Observatory’s Large Telescope located in the Atacama Desert in Chile. The biggest discovery is this: the star’s orbit shaped like a pink window.
Why is this important? Because two orbital theories were fighting: Isaac Newton’s theory of gravity suggested that the orbit should look like a fixed ellipse while Einstein’s theory of relativity argued that it should look like a pink window. This is proof that Einstein was right.
“Einstein’s general relativity predicts that the orbits bound by one object around another are not closed, as in Newtonian gravity,” said Reinhard Genzel, director of the Max Planck Institute for Physics, in a statement.
If we have known since elementary school that the planets revolve around the sun in a frozen ellipse orbit, then this is not really the case.
You may not know it but ‘this famous effect [rosace NDLR] – First seen in the orbit of the planet Mercury around the Sun – it was the first evidence in favor of general relativity, explains Genzel.
Supermassive black hole at the center of our galaxy
This effect can then be re-examined near another element of our galaxy, the supermassive black hole we didn’t know existed not so long ago, Sagittarius A*, which lies 26,000 light-years from the Sun.
“One hundred years later, we have now detected the same effect in the motion of a star orbiting Sagittarius A* at the center of the Milky Way. This observation strengthens the evidence that Sagittarius A* must be a supermassive black hole 4 million times the mass of the Sun.”
The black hole attracts many dense stars around it, and one of them, called S2 (a simple one-time name), passes as close as possible to the black hole, less than 20 billion kilometers away (in astronomical terms, that’s a close distance). As it approaches Sagittarius A*, the star is moving at 3% of the speed of light.
Astronomers have been observing the star’s motions for nearly 30 years and have been able to clearly detect the change in the orbit of S2 as it orbits the black hole. Orbits are never perfect circles, celestial bodies move closer or farther as they rotate. But this time, not only was the star not rotating in circles, but in addition, its approach to the black hole changed every time, creating the shape of the rose window. Einstein’s theory predicted this change in orbit.
Clearer measurements with a larger telescope
If this news is really incredible, then future telescopes, more powerful, will make it possible to observe smaller stars closer to the black hole and be able to prove other elements of Einstein’s theory.
“With luck, we may catch stars close enough that they actually feel the rotation of the black hole,” said Andreas Eckart, study co-author and lead scientist on the University of Cologne project in Germany. “This will again be a completely different level of relativity testing.”
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RTBF/MCP, via mediacongo.net
