https://www.sciencenews.org/article/star-orbiting-black-hole-einstein-gravity-general-relativity
In a paper published July 26, 2018 in Astronomy & Astrophysics, a team of researchers reports the observation of a hallmark of general relativity known as gravitational redshift. The measurement is the first time general relativity has been confirmed in the region near a supermassive black hole.
In fact, GPS satellites would fail to function properly if gravitational redshift weren’t taken into account.As light escapes a region with a strong gravitational field, its waves get stretched out, making the light redder, in a process known as gravitational redshift. The scientists, a team known as the GRAVITY collaboration, used the Very Large Telescope array, located in the Atacama Desert of Chile, to demonstrate that light from the star was redshifted by just the amount predicted by general relativity.
Scientists have observed gravitational redshift before. In fact, GPS satellites would fail to function properly if gravitational redshift weren’t taken into account.
