Astronomers already use another effect predicted by Einstein's theory of general relativity - that a black hole can bend passing light. This event is reportedly consistent with the predictions from Einstein's theory of general relativity.
The legendary scientist theorized that when light moves within a strong gravitational field its wavelength would actually stretch as though it's being stretched by the pull of gravity.
The team of scientists at the European Southern Observatory started monitoring the central area of the Milky Way using its Very Large Telescope to observe the motion of stars near the supermassive black hole 26 years ago. "But this time, because of much improved instrumentation, we were able to observe the star with unprecedented detail resolution", explains Richard Genzel, Director of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching near Munich, and head of the global team of scientists.
During May 2018, the star closed by the supermassive black hole at 20 billion kilometers and accelerated to 3% of the speed of light which is very fast for a star.
"And the change in the wavelength of light from S2 agrees precisely with that predicted by Einstein's theory of general relativity".
Erin VanDyke lives on her family farm and has more than 35 years of hands-on experience with the use of livestock guard dogs for predator control. The star passed close enough to the black hole - and was observable, at the same time - in May of 2018.
"We have put enormous effort into getting the instruments into good shape before the star approached the black hole", said Thibaut Paumard, a researcher at the French National Research Institute, the CNRS, in Paris.
"The new measurements clearly reveal an effect called gravitational redshift", the astronomers said.
"More than 100 years after he published his paper setting out the equations of general relativity, Einstein has been proved right once more - in a much more extreme laboratory than he could have possibly imagined", said the ESO in a statement.
Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany said, "This is the second time that we have observed the close passage of S2 around the black hole in our galactic center". They also used GRAVITY instrument in the VLT Interferometer (VLTI) that unveils the motion of the star from night to night as it passes close to the black hole. his long-sought result represents the climax of a 26-year-long observation campaign using ESO's telescopes in Chile.
"I am always blown away by Einstein's predictions, by the power of his reasoning which yielded this theory and which has never been faulted", French astrophysicist Guy Perrin, a member of the GRAVITY consortium, told AFP.
The team compared S2's position and velocity measurements to previous observations and found the results to be in agreement with Einstein's gravity predictions. The black hole at the centre of the galaxy is about 10 times the size of the sun in diameter, but has a mass of about 4m solar masses. Several of its components have been proven over the years, but this is the latest. In this context, Sgr A* is an ideal environment for testing Einstein's theory of relativity, since the stars that surround it are in the most intense gravitational field of the galaxy.
This is the first time observers have been able to measure such an effect.