Thanks for this nice blog. I must however react to one of the paragraphs you wrote, and with which I strongly disagree.
Despite this, there is something in the entire cosmos that maintains the same temperature to an accuracy of one part in 100,000. In point of fact, the difference is so negligible that 0.000018 degrees Celsius is all that can be said to differentiate a warm region from a cold one.
In fact, those differences are not negligible at all. We can measure them and use them to get insight on how the universe was 380,000 years after the Big Bang. This gives powerful constraints on many particle physics extensions of the Standard Model.
Therefore, whereas the relative temperature differences in the cosmic microwave background are small, this is not a good reason to claim that they are negligible.
Thank dear @lemouth for pointing that out. Well, the thing is that I am currently undergoing a study on this topic. So I will keep improving as time goes on
Sure! Take your time and don't hesitate to tag me to ask questions. The cosmic microwave background is something I know quite well :)