Star’s orbit around black hole proves Einstein’s theory of relativity
Berlin, Apr 16 (efe-epa).- The path of a star orbiting a supermassive black hole has confirmed Albert Einstein’s theory of relativity, the European Southern Observatory announced Thursday.
Scientists were able to observe the movement of the star around a black hole at the centre of the Milky Way for the first time using the Very Large Telescope (VLT) at the ESO’s observatory in Chile.
The rosette shape of the orbit was as predicted by Einstein’s theory of relativity, rather than an ellipse which would have matched Isaac Newton’s theory of gravity.
This research was the result of precise measurements taken over almost 30 years which enabled scientists to “unlock the mysteries of the behemoth lurking at the heart of our galaxy”, ESO said in a statement.
Reinhard Genzel, director at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, and architect of the project, said: “Einstein’s General Relativity predicts that bound orbits of one object around another are not closed, as in Newtonian Gravity, but precess forwards in the plane of motion.”
The evidence of this was first seen in the orbit of the planet Mercury around the Sun, he added.
“One hundred years later we have now detected the same effect in the motion of a star orbiting the compact radio source Sagittarius A at the centre of the Milky Way,” he continued.
The observational breakthrough strengthens the evidence that Sagittarius A is a supermassive black hole around four million times the mass of the Sun, according to Genzel.
Located 26,000 light-years from the Sun, the black hole and dense cluster of stars around it provide a unique laboratory for testing physics in an “otherwise unexplored and extreme regime of gravity”, the ESO said.
One of these stars, S2, moves in towards the supermassive black hole at a closest distance of less than 20 billion kilometres, 120 times the distance between the Sun and Earth, making it one of the nearest stars found in orbit around the massive giant.
Most stars and planets have a non-circular orbit, meaning they move closer and further away from the object around which they revolve.
S2’s orbit has a precessive motion, which means its closest point to the supermassive black hole changes with each orbit, so that the next route rotates relative to the previous one, creating a rosette shape.
Einstein’s theory of relativity gives an accurate prediction of how much the orbit changes and the latest measurements from the research exactly matched the theory, according to the ESO.
This effect, known as the Schwarzschild precession, has never been measured before in a star around a supermassive black hole. EFE-EPA
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