Eli5 If the universe expanded from a single point why do scientists say its flat and not spherical?

Question

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

Answer 1

It is three dimensionally flat, which just means that it isn’t curved in the fourth dimension.

Gravity curves space in the fourth dimension which is why we fall towards the center of gravity wells. Overall, the whole of space, that we can see, is flat, not curved.

Any deeper and this is way past a ln eli5.