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Can we observe the CMB changing with time?
ok, so the cosmic microwave background should be time dilated, by a factor of about 1000. still, WMAP has observed it for 7 years or so, or about 2.5 days at the emitting surface. are there any predictions for how fast it should change, and are we anywhere near being able to see such changes?
Morningfox: it isn't just the black body temperature that's changing though, is it? what about the anisotropies?
1 Answer
- MorningfoxLv 71 decade agoFavorite Answer
The temperature of the CMB is Tr = 2.735 K. Since decoupling, the temperature of the background radiation has dropped by a factor of roughly 1,100.
The temperature should now be dropping by about 6 nano-degrees per year, which is way below the limit that we can detect. But in about a million years, it will be 2.729 degrees
I don't think of it as being time dilated. It's more like it's spread out into a larger and larger universe.
