Chapter 10Science & Nature

Is the universe really expanding?

Yes — every galaxy outside our local group is moving away from every other, and the rate is accelerating (attributed to 'dark energy'). Not into anything; space itself is stretching.

Follow-up questions

What was before the Big Bang?

The honest answer: unknown. 'Before' may not even be a meaningful concept if time itself started with the Big Bang.

Will it end?

Current best guess: continued expansion into a cold, empty 'heat death' trillions of years from now.

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