Cosmology: Where Did We Come From?

Did the universe have a beginning, and how could we possibly know? We turn from space to time and run the movie backward.

We've explored the universe in space, out to the cosmic web and the dark 95%. Now we turn the journey from space to time and ask the oldest question there is: did everything have a beginning?

The answer, astonishingly, is one we can investigate with hard evidence. We'll discover that the universe is expanding (so it was once smaller, hotter, and denser), rewind that expansion to the Big Bang about 13.8 billion years ago, look at the universe's actual baby photo glowing in every direction, watch the first elements get forged, and finally squeeze all of cosmic history into a single calendar year — where all of human history fits in the last few seconds before midnight.

The Expanding Universe: Everything Is Rushing Apart

Nothing is flying through space away from us. Space itself is stretching — like raisins drifting apart in rising bread.

45m

The Big Bang: Running the Cosmic Movie Backwards

It was not an explosion in space. It was space itself, everywhere at once, beginning to stretch — and the difference matters.

30m

The Universe's Baby Photo: The Cosmic Microwave Background

The oldest light there is, released 380,000 years after the beginning — and a sliver of old analog TV static was always part of it.

45m

Building the Elements and the Cosmic Calendar

Where every atom in you came from, and what 13.8 billion years looks like squeezed into a single calendar year.

45m

What you'll carry out of this section

Why we know the universe is expanding — and that space itself stretches.
What the Big Bang theory really claims, and the myths it doesn't.
The cosmic microwave background — the universe's baby photo, and the Big Bang's best evidence.
Where the elements came from, and a gut feel for deep time via the Cosmic Calendar.