Friday, July 27, 2018

Gravitational Red Shift Shows That Einstein Is Right Once More!

Albert Einstein's General Relativity is 3-for-3 this year so far! We already had GR passing its first galactic-scale test, and then we had the verification of the strong equivalence principle. This time, observation of light from a star in our Milky Way passing near a supermassive black hole has shown the predicted gravitational red shift. Holy Cow, Batman!

The team compared the position and velocity measurements from GRAVITY and SINFONI respectively, along with previous observations of S2 using other instruments, with the predictions of Newtonian gravity, general relativity and other theories of gravity. The new results are inconsistent with Newtonian predictions and in excellent agreement with the predictions of general relativity.
The new measurements clearly reveal an effect called gravitational redshift. Light from the star is stretched to longer wavelengths by the very strong gravitational field of the black hole. And the change in the wavelength of light from S2 agrees precisely with that predicted by Einstein’s theory of general relativity. This is the first time that this deviation from the predictions of the simpler Newtonian theory of gravity has been observed in the motion of a star around a supermassive black hole.

A copy of the paper (or maybe a preprint) can be found here.

It bears repeating: the more they test it, the more convincing it becomes!


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