English subtitles for clip: File:Welche Form hat das Universum?.webm

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Can the Universe be infinite?

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A thought experiment.

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Imagine the universe
reduced to two dimensions –

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everything can now only move
move in this plane.

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Even in the 2D universe
our view into the depths is limited.

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We only see our
observable section.

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Behind this, the universe could
could theoretically go on indefinitely.

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Hard to imagine, but the rocket
would never reach an edge.

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But it could be completely different:

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The universe could be curved,

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like the surface
of a giant ball.

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Then it would also be without an edge,
but not infinite:

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The rocket would come back to
the start at some point.

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Such a huge curvature of the universe

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would be hard to prove in the limited,
observable section.

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And in fact astronomers have
so far not been able to

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find any indications for this.