Let's see if I've got this right - we can see objects between the event horizon and the surface of last scattering because even though those objects are moving away from us faster than light right now thanks to the accelerating expansion of the Universe, they used to be travelling more slowly than they are now and light from them was able to reach us? Or is it just that the farther away they are, the faster they're receding, so they used to be inside the event horizon when they emitted the light and they've now moved beyond it? Also, in the old steady state model, assuming no Big Bang and a constant Hubble constant (ruled out by current observations, of course, but a popular model back in the day!), would the boundary of the observable Universe actually be the cosmic event horizon? There'd be no acceleration there, but galaxies farther away would be receding faster, so galaxies within the event horizon could pushed beyond it. So maybe we'd see galaxies some distance beyond the event horizon, but... not infinitely far? Would there be a second event horizon?
So it would seem that, according to the explanation, that the particle horizon is the farthest we can see a distant object. However, if we say look at the CMB we are NOT looking 4out 6 billion light years , but only 14 billion (13,77). Aren't we seeing photons from the CMB , that were much closer to us when tey were emitted,? For the life of me, I have never bumped up against clarity in this. If we see light from a galaxy that left it when the galaxy was 294 million years from us,, aren't we seeing the galaxy as it looked 294 million years ago, even though it is 306 million light years away? So we're not seeing this galaxy at 306 million light years distant, but at 294 million light years distant. Correct? So how is the observable universe 46 billion light years, when we are observing it at 13.7 billion light years?
Great video. I have been interested in this subject for some years and I find it very useful to watch this kind of video to reinforce my knowledge.
Thanks for this wonderful video
Thank you
Let's see if I've got this right - we can see objects between the event horizon and the surface of last scattering because even though those objects are moving away from us faster than light right now thanks to the accelerating expansion of the Universe, they used to be travelling more slowly than they are now and light from them was able to reach us? Or is it just that the farther away they are, the faster they're receding, so they used to be inside the event horizon when they emitted the light and they've now moved beyond it?
Also, in the old steady state model, assuming no Big Bang and a constant Hubble constant (ruled out by current observations, of course, but a popular model back in the day!), would the boundary of the observable Universe actually be the cosmic event horizon? There'd be no acceleration there, but galaxies farther away would be receding faster, so galaxies within the event horizon could pushed beyond it. So maybe we'd see galaxies some distance beyond the event horizon, but... not infinitely far? Would there be a second event horizon?
So it would seem that, according to the explanation, that the particle horizon is the farthest we can see a distant object. However, if we say look at the CMB we are NOT looking 4out 6 billion light years , but only 14 billion (13,77). Aren't we seeing photons from the CMB , that were much closer to us when tey were emitted,? For the life of me, I have never bumped up against clarity in this. If we see light from a galaxy that left it when the galaxy was 294 million years from us,, aren't we seeing the galaxy as it looked 294 million years ago, even though it is 306 million light years away? So we're not seeing this galaxy at 306 million light years distant, but at 294 million light years distant. Correct?
So how is the observable universe 46 billion light years, when we are observing it at 13.7 billion light years?