Why would it only expand in one plane not every direction like you’d expect?
Also how is a flat universe even possible? Surely since we live in 3 dimensions the universe needs to be a 3 dimensional shape.
Im probably misunderstanding what physicists are trying to say but that’s why im here.
In: 229
You’re correct, we do live in a 3D world. they’re not talking about dimensions, they’re talking about how geometry works in our universe.
Imagine you’re on the equator of the earth. Walk straight forward to the North Pole, turn 90 degrees, and walk straight down, back to the equator. Then turn 90 degrees again and walk back to exactly where you were at the start. You’ve walked 3 straight lines, and turned 90 degrees three times, and yet you’ve somehow made a triangle. This is called spherical geometry, it’s very different from the “flat” Euclidean geometry were used to on paper, where triangles cannot be made with 3 right turns.
Obviously this is a 2D example, and it’s hard to make a 3D analogue, but that’s what scientists are talking about with flat or spherical space.
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