Einstein’s Predictions Proven Right With A Star’s Incredible Black Hole Encounter
Thousands of light-years from Earth, a star wanders close to a supermassive black hole and proves Albert Einstein's theory of general relativity correct.
Einstein's theory of general relativity has withstood the test of time, shown to be accurate over and over again throughout the past century. In the star S2's decades-long journey around a black hole in the heart of the Milky Way galaxy, the theory passed its most rigorous test yet.
Scientists Observe Gravitational Redshift
According to a report from the European Southern Observatory, at the center of the Milky Way galaxy is what's widely believed to be a supermassive black hole. Just 26,000 light-years away from Earth, it's the closest black hole to the planet and is orbited by a group of stars traveling at great speed.
In May, one of the stars called S2 whizzed extremely close to the monstrous black hole and passed through its extreme gravitational field. The star went as close as just 20 billion kilometers from the black hole as it moved over 25 million kilometers per hour.
Scientists have been tracking this star with ESO's Very Large Telescope for 26 years in anticipation of this encounter.
At these extremes, Gizmodo points out, Isaac Newton's laws of gravity no longer applies. Instead, Einstein's theory in general relativity steps in and proves itself in unprecedented fashion.
In a paper published in Astronomy & Astrophysics, scientists reveal that the black hole's intense gravitational pull stretched S2's light waves longer, just as Einstein predicted in his theory of general relativity. This effect is known a gravitational redshift.
"This is the second time that we have observed the close passage of S2 around the black hole in our galactic center. But this time, because of much improved instrumentation, we were able to observe the star with unprecedented resolution," lead researcher Reinhard Genzel, who is from the Max Planck Institute for Extraterrestrial Physics, explains in a statement to ESO. "We have been preparing intensely for this event over several years, as we wanted to make the most of this unique opportunity to observe general relativistic effects."
More Observations Expected Out Of S2
Despite the impressive findings on S2's behavior as it passes through the black hole, the team's work isn't quite done yet. There are more secrets to uncover — and as is the nature of science, Einstein's theory of general relativity will never be safe from scrutiny.
Another prediction of general relativity that scientists will be testing is the star's precession, which means the orbit's shape rotates, according to Gizmodo. By 2020, it's possible that the scientists may have enough data to confirm the precession.