- #1
Holocene
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I just want to make sure my understanding is correct.
In a "flat" universe, the total density of the universe matches the "critical density". As a result, the universe will expand forever, and never "fall back" into itself.
The shape of a flat universe, as the name suggests, is flat like a piece of paper.
In a flat universe, the Pythagorean theorem hold true, even when applied to distances of many billions of light years. This is because a flat universe does not curve in any way, except of course for the areas where space-time is curved around massive objects, including black holes.
Now for a question:
Is it correct to think of the flat universe of a sphere that will never stop expanding? I ask this because, if this is true, then the shape of the universe at any given time would be a sphere, and therefore would in fact be curved.
Or should I think of the flat universe as a "cube" that will keep expanding?
In a "flat" universe, the total density of the universe matches the "critical density". As a result, the universe will expand forever, and never "fall back" into itself.
The shape of a flat universe, as the name suggests, is flat like a piece of paper.
In a flat universe, the Pythagorean theorem hold true, even when applied to distances of many billions of light years. This is because a flat universe does not curve in any way, except of course for the areas where space-time is curved around massive objects, including black holes.
Now for a question:
Is it correct to think of the flat universe of a sphere that will never stop expanding? I ask this because, if this is true, then the shape of the universe at any given time would be a sphere, and therefore would in fact be curved.
Or should I think of the flat universe as a "cube" that will keep expanding?