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
The big bang was an explosion where you – yes you! – is sitting in its middle, as all of the universe. When we look into the sky you look into far distances and at the same moment backwarts in time. And if you look far enough away then you also look back into a time when the explosion occures. The light is streched to the expanding universe and therefore its frequency, too. And it is now so much streched, that we “see” it as a microwave radiation.
Latest Answers