The Universe is 13.8 billion years old, going back to the hot Big Bang. But was that truly the beginning, and is that truly its age?

Key Takeaways

If we count from the start of the hot Big Bang, we learn that the Universe is 13.8 billion years old, with only a very tiny (~1%) degree of uncertainty.

But what gives us the right to call the start of the hot Big Bang “the beginning,” particularly if we now can confidently state that a period of cosmic inflation preceded it?

The reality is that we have to make choices, and the start of the hot Big Bang is one of the earliest things we can be certain about. Here’s what the “age of the Universe” actually means.