Epoch (astronomy) by Ciro Santilli 37 Updated 2025-07-16
If looking through these don't make you think of the Book of Genesis then nothing will.
There is a slight variation in temperature of CMB across the sky of the order of 200 microKelvin. It is small to the ~2.7 K average temperature, but it can be measured.
If the initial conditions of the Big Bang and the laws of physics were perfectly symmetric, then we could expect the universe to just be one perfectly uniform boring soup.
But instead some asymetry made all the fun weird things we see today happen eventually, like galaxies and life.
And the cosmic microwave background serves as a way for us to look back in time to the early conditions of the universe, as it was set in stone as soon as the universe became transparent to this light during recombination.
Or if you want to get poetic, it is the closest we can ever get to listening to the original word of God when he setup the initial conditions of the universe.
The ansiotropies of CMB is the ultimate astronomical compass we will ever have, as it is the thing with the least proper motion.
Figure 1.
Cosmic microwave background anisotropy measured by the Wilkinson Microwave Anisotropy Probe
. Source.
Some people have been creating YouTube channels that just post and go over a large number of Stack Exchange questions, some of them with a quick random intro video. Perfectly legal due to CC BY-SA but really weird stuff!
Figure 1.
Cosmic microwave background anisotropy measured by the Wilkinson Microwave Anisotropy Probe
. Source.
And translating from their arcane vocabulary:
  • Prelims: first year undergrad
  • Honour school; other years of undergrad, sometimes it includes masters others not which is confusing
  • MPhil, MSc, MSt: masters
This one took a while! Major developments were from the 70s! Perhaps it took the Internet revolution to make its importance clear.

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