This question already has an answer here:

I have read this question:

Redshifting of Light and the expansion of the universe

Now analogously, we could talk about GWs traveling in the empty voids of space, where the expansion of space is dominant.

There is a debate over whether gravitons exist or not, and whether gravitons are the quanta of GWs or not, by let's assume yes.

Just as EM waves wavelength get stretched as they travel in expanding space, GWs wavelength could get stretched.

We are actually able to measure the redshifting of EM waves from far away sources. We could be able to measure the redshifting of GWs from far away sources as we have already detected GWs.


  1. Can expanding space stretch the wavelength of GWs?

  2. When we detected the first GWs, did we measure the actual amount of redshift they went through as they traveled from the source?


marked as duplicate by Void, Ben Crowell general-relativity Apr 8 at 23:30

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.


According to general relativity gravitational waves are affected by gravitational redshift in exactly the same manner and extent as electromagnetic waves.

A complicating matter is that the effect of redshift on a gravitational wave signal is fully degenerate with the total mass of its sources. Consequently, it is not possible to determine the redshift from the a gravitational wave observation alone.


Not the answer you're looking for? Browse other questions tagged or ask your own question.