THE COSMIC MICROWAVE BACKGROUND. This is the ninth anniversary of the day I began this blog with a post in which I expressed my wonder that background radiation from the Big Bang makes up a lot of the static you hear on the radio. I continue to be fascinated by the background radiation. Here is an article by Ethan Siegal at the Starts with a Bang web site about the cosmic microwave background. Siegel starts by calling it the “leftover glow from the Big Bang.” He quotes Steven Hawking: “The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to -271.3°C, not much good for defrosting the pizza, let alone cooking it.”
Siegal says: “So that’s the first prediction of the Big Bang about this radiation: it should be uniform in Temperature, just a few degrees above absolute zero, and should come equally from all directions in space.” And that’s what the cosmic microwave background is.