I can’t get my head around how we measured the radiation from the Big Bang in order to discover how old the universe really is. How does that specific radiation differ from many other types of radiation? Newest findings suggest that the age of the universe has been mistaken not because of an error in calculations, but because of some kind of error in the understanding of the nature of cosmos itself. While I will probably not think up anything remotely usefull to anybody, I’d like to understand this part – please help a humble redditor.
The cosmic microwave background radiation is what we think is a remnant of the Big Bang because it’s generally uniform – i.e. it’s coming from everywhere, and not one particular source. This suggests that it happened as a result of the Big Bang’s expansion, and as the universe expanded, this radiation became thinner, less dense and colder and allowed other elements to form and bind. But that’s how it’s different from other sources as far as I can tell – other radiation comes from specific sources we can identify, like a star or a black hole, etc. CMB is generally everywhere and mostly uniform, and consistent with the expansion of the universe.