Ask Ethan: How did we prove the Big Bang took place?

Of all the great mysteries out there in the Universe, perhaps the greatest one of all is the question of our cosmic origin, “where did all this come from?” For countless millennia, we told one another stories: of a fiery birth, of the separation of light from dark, of order emerging from chaos, of a dark, empty, formless state from which we emerged, or even of an existence that was eternal and unchanging. Some stories involved an active creator; others needed no intervention from anything other than nature itself. But despite our propensity to believe in one of these stories or another, in science, we don’t settle for belief: we want to know. Today, we talk about the Big Bang as though it’s foundational and taken for granted. But that wasn’t always the case. So how did we get to this point? What critical scientific steps occurred to promote the Big Bang from just one among many ideas to a scientific certainty? That’s what Muhammed Ayatullah wants to know, as he writes in and asks, simply and straightforwardly: <a href="https://medium.com/starts-with-a-bang/ask-ethan-how-did-we-prove-the-big-bang-took-place-98d94eda3349">Website</a>