This question follows from a schooling I received in this thread. I figured that photons do not interact with gravity, except when they've spontaneously converted into a particle-antiparticle pair. ...
I read on a post Big Bang and Cosmic microwave background radiation? We detect light from another 13 billion years ago does this mean that one billion years ago we could only detect light from about ...
I think the title says it. Did expansion of the universe steal the energy somehow?
If a photon (wave package) redshifts (streches) traveling in our expanding universe, is it's energy reduced? If so, where does it go?
Introductory texts and popular accounts of why we see the "once hot" CMB as microwaves nearly always say something about the photons "cooling" since the Big Bang. But isn't that misleading? Don't ...