The hot Big Bang is often touted as the beginning of the Universe. But there’s one piece of evidence we can’t ignore that shows otherwise. — The notion of the Big Bang goes back nearly 100 years, when the first evidence for the expanding Universe appeared. If the Universe is expanding and cooling today, that implies a past that was smaller, denser, and hotter. In our imaginations, we can extrapolate back to arbitrarily small sizes, high…