I am trying to grasp the concept of cosmic background radiation, specifically why we can still see it today. As the name implies, it is very faint radiation from the very early universe.
What I don’t get: if a very distant star stops emitting radiation then it will disappear from our view.
As far as I understand it, CBR originated with the recombination. That phase took a few hundred thousand years, then it stopped. So why can we still see the photons emitted then?
Thanks for illuminating me.
In: 6
Thanks everybody for your explanations. I understand the distance – time relationship, expressed in light years.
What I am having difficulty with is the timing, I guess. If I think of the CBR being emitted as a fireworks being lit up ( and then fading away), the fireworks lasted 100 k years or so. So it strikes me as a coincidence, that we are seeing photons from an event that only lasted 100 k years.
Or phrased differently: why are there CBR photons all over the place apparently?
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