The discussion revolves around the experimental verification of light's wavelength compression due to gravity, specifically addressing whether there is evidence for gravitational blueshift, in contrast to the established phenomenon of gravitational redshift. The scope includes theoretical implications and historical experiments related to gravitational effects on light.
Participants express uncertainty regarding the existence of experimental proof for gravitational blueshift, while acknowledging that gravitational redshift has been well established. There is no consensus on whether compression has been definitively proven.
Some discussions reference historical experiments and their setups, but there are limitations in the clarity of whether these experiments directly address the question of wavelength compression.
The X-rays emitted by matter falling into black holes were a prediction of gravitational redshift via GR. They have been observationally verified.billy_boy_999 said:
russ_watters said:
Good question! One of the early 'gravitational redshift' experiments was (IIRC) a 57Fe gamma Mossbauer effect, over a vertical distance of several (tens of?) metres. I don't know if the experimenters went on to put the source on a higher storey of the lab building, and the detector at a lower one ...billy_boy_999 said:
