The universe is full of mysteries, but its age isn't one of them. That's because the universe left behind a huge number of clues as to its age — including the observed age of the oldest stars; the rate of expansion of the universe; and the background heat of the universe, which hints at how long it's been since it cooled off from the Big Bang. All of these data points, measured many times in different ways, point to a universe that expanded from a single point some 13.7 billion years ago.
But once in a while, something weird comes along that doesn't fit with that timeline.
