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2019-12-09: The Doomsday Argument

  • 14:06: ... finite or infinite because it may be that there's a slight positive or negative curvature just beyond the sensitivity of our ...

2019-12-02: Is The Universe Finite?

  • 04:26: Rapid expansion tends to give negative curvature and open the universe - make it infinite.

2019-04-10: The Holographic Universe Explained

  • 11:15: While the original space was flat, the new space had negative curvature – it was a hyperbolic, anti-de Sitter or AdS space.
  • 16:40: KI9 asks whether the things we learn from AdS/CFT are applicable to the universe we live in given that our universe doesn't have negative curvature.
  • 16:50: ... we don't know for sure that it doesn't have negative curvature - just that any curvature - negative or positive - is very weak compared ...

2019-04-03: The Edge of an Infinite Universe

  • 03:25: Finally there’s the universe with negative curvature, and the 2-D analog of that is the hyperbolic surface, like an infinite saddle or pringle.

2019-02-20: Secrets of the Cosmic Microwave Background

  • 07:42: ... effect On the other hand an expanding universe with no energy would have negative curvature So a flat universe must have exactly the right amount of energy to ...

2019-01-30: Perpetual Motion From Negative Mass?

  • 08:01: Negative mass causes negative curvature, which in our sheet analogy looks like pulling the sheet up.

2017-11-08: Zero-Point Energy Demystified

  • 05:36: That means the vacuum energy between Casimir plates still produces positive spatial curvature, not the negative curvature required for warp drives.

2016-03-23: How Cosmic Inflation Flattened the Universe

  • 02:00: On a negative curvature hyperbolic plane-- a saddle-like structure-- they add up to less.
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