Is it true that light escaping from white dwarfs will show a gravitational redshift?

1 Answer
Dec 23, 2015

Yes.

Explanation:

The small size and high density of white dwarf stars means that the gravitational red shift is much stronger than for less dense stars like our sun. A typical white dwarf might have a similar mass to our sun but be about #1/100#th of the diameter. Since gravity is inversely proportional to the square of the distance, that means that the surface gravity of a white dwarf would be about #10000# times that at the surface of the sun.

As far as I know the first really successful observations of such gravitational red shifts from white dwarf stars were made during the 1950's, agreeing with the predictions of general relativity.