I think it does, but I’m not certain if the question has been really studied. When looking at the pattern of redshift in light from distant galaxies, the assumption is that the photon and it’s wave have only interacted with the medium through which they have traveled. It has stretched and thus their wavelengths have stretched and they become more red over time. For billions of years that light has traveled otherwise unimpeded by the vast amount of matter that populates the empty reaches of space and strikes our detectors delivering it’s payload of ancient information to it’s final destination. This seems to be a reasonable enough description of what we observe, however I don’t like assumptions.

Since we accept that the photon is effected by the medium, and gravity waves are the medium, it stands to reason there is at least the possibility that photons interact with gravity waves.

When Einstein found his equations describe an expanding universe he rejected the idea, when redshift was observed as a function of distance he disregarded his reservations and embraced the idea. His equations also showed that light would shift to the red end of it’s spectrum if it passed by a large gravitational body. This again demonstrates an inherent relationship between photons and gravity.

The reason I’m curious about this is because other correlations seem to arise all on their own if it does. The success of the LIGO has all but proven gravity waves of very high energy are extraordinarily common. Perhaps as many as half a dozen every few months. Which would imply gravity waves of lower energies are likely equally as common if not moreso but this has yet to be proven given the limits of current technology.

Now extrapolating that out a photon travelling through open space for ten billion years will interact with or at the minimum pass directly through a massive amount of gravitational energy over time. It will encounter a huge huge number of large gravity waves that we know of and perhaps equally as many that we don’t.

This means that the further we look back in time, the more chances any single photon has had to interact with gravity waves. If that interaction were to make just the tiniest nearly imperceptible shift in it’s spectra and it happened a dozen times a year for billions of years there would have to be a measurable effect.

All of that gravity that a photon has to travel through, all of those expelled buckles in space, would mean the intervening space between us and a distant galaxy isn’t an empty fabric, but rather would act on the photon like a gravitational body whose weight was the sum total of the accumulation of all the gravity waves it passed through. That total would be it’s Z.

I was wondering if photons interact with gravity waves, because if they do then redshift could be caused not by expansion, but by the weight of space given to it by the collision of massive bodies littered throughout it’s expanse expelling their gravity into the cosmic void. Rendering space itself like a large gravitational body any photon has to pass by and through to get wherever it goes.

The question remains does a photon interact with gravity waves?

Perhaps the answer is self evident, but I’ll go out on a limb and say yes, I think it does…