• Question: Why is the universe so exquisitely balanced such that life can exist?

    Asked by BBshorty to Susan, Chris, Josh, Rebecca, Rob on 16 Jun 2015. This question was also asked by charliebam.
    • Photo: Susan Cartwright

      Susan Cartwright answered on 16 Jun 2015:

      Because we exist!

      We could not possibly observe a universe in which life could not exist, so we MUST see a universe in which life can exist. (This is known as the “weak anthropic principle”.)

      It is not entirely clear how difficult to achieve a life-friendly universe is – some people think it’s extremely improbable, while some are much more optimistic. If the models that predict many universes are right, this doesn’t matter – we would always end up in a universe that can support our kind of life, even if 99.99999999999% of the universes out there could not.

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