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PBS Space Time
Why the Universe Needs Dark Energy
Season 2
Episode 27
We know the universe will continue to expand forever, so now we can begin to complete the first Friedmann equation, and determine the shape and geometry of our universe. At first glance, it would seem that the equation doesn’t quite add up, and that our universe is a hyperbolic plane. But when we add in the cosmological constant, the equation balances out, and we return to a flat universe.
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