This video http://youtu.be/_mZQ-5-KYHw talks about the background radiation which we can observe today. It's from the beginning of the universe and has traveled so long that the expansion of the universe has changed its wavelength to microwaves, instead of visible light.
The way the video describes it i would think that as some point the waves from the background radiation would have to not be observable anymore, because they have been absorbed by an object along the way. Could they lose energy and not only their wavelebgth gets super long, but also their amplitude very low? And finally: will the universe at one point expand so fast (faster than light speed) that the background radiation waves cant ever catch up to us and we wont be able to observe them? If it ever should cease to be observable by us, when would that be approximately?
As i stated in the title: Will the background radiation get "dimmer"? If so when will it be "turned off"
