How, you might ask, can we verify something that happened 14 billion years ago? Well, the theory of inflation predicts specific signatures in the tiny ripplings of the cosmic microwave background that we should see today, and some of those signatures seem to be present in experimental measurements of the CMB. Of course, this doesn’t mean that we know inflation is real because there are other theories that also predict such wiggles, but it lends weight to it. In fact, this is also how we know that the universe started about 14 billion years ago. From those ripples, we can estimate the
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