cosmology – Identifying the Micro behind the Macro

What caused the expanding universe to cool? (It may not be what you think)

Expansion leads to cooling. That’s what I was taught anyway. And so when I read that the expansion following the Big Bang caused the universe to cool, I first thought, “okay…” But then I thought some more. “Wait a minute! Expansion against what???” The reason a system cools as it expands it that it pushesContinue reading “What caused the expanding universe to cool? (It may not be what you think)”