I have been googling Cosmic Background Radiation, but am still confused as to the location of its source. Is it just very old light finally arriving from very distant sources? Or is earth also surrounded by nearby CBR sources that in the fullness of time will arrive at very distant galaxies?
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>Or is earth also surrounded by nearby CBR sources that in the fullness of time will arrive at very distant galaxies?
This is closer to the truth. CBR is everywhere. “The fullness of time” is every moment since the cosmos “cooled” enough for photons to travel through empty space between other substance. Every point in space (including every distant galaxy, no matter how far away) are being pummeled by these photons. The “distance” to where the apparent sphere of photons from that long ago moment seem to be “coming from” is equally distant from every point at the same time. No matter where you are in the universe, “the CBR” looks equally far away, because it is a measure of how long ago that radiation first started, plus the speed of light (and the expansion of space).
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