I've also wondered about Op's question. What happens as photons continue to redshift? Is there some ultimate redshift where the photon just fades away? Or is this a case of we don't know because we can't observe photons below frequency f. By the way, what is the lowest frequency longest wavelength photon that is observable by state of the art equipment?
jmarkmorris t1_jcnbw8p wrote
Reply to comment by extra_specticles in Where do photons go if they've been emitted but are destined to never be absorbed, and would these photons traveling ad infinitum define the edge of the universe (even if space itself were still larger)? by mysteryofthefieryeye
I've also wondered about Op's question. What happens as photons continue to redshift? Is there some ultimate redshift where the photon just fades away? Or is this a case of we don't know because we can't observe photons below frequency f. By the way, what is the lowest frequency longest wavelength photon that is observable by state of the art equipment?