WinBarr86 t1_iycyqim wrote on November 30, 2022 at 2:07 PM

Perspective.

Take a sheet of paper for example, we call it 2d, but it is infact a 3d object. It has 3 dimensions. It's just the thickness is so small in relation to the other dimensions we kinda pretend it isn't there.

We call it flat for lamens purposes. It makes a few things easier to understand on a basic level.

Edit.

Flat doesn't always mean 2d. You can have a flat 3d object. Like paper.

nhabz OP t1_iycyvc7 wrote on November 30, 2022 at 2:08 PM

So the universe is actually 3D but we call it 2D to make certain concepts easier to understand?

ialsoagree t1_iyd0byk wrote on November 30, 2022 at 2:20 PM

No no, we call it flat - but flat doesn't mean 2D.

We call paper flat, but paper isn't 2D, it's 3D.

WinBarr86 t1_iyd0ohk wrote on November 30, 2022 at 2:23 PM

We don't call it 2d we call it flat.

Flat is a concept. That concept is easier to explain using a 2d method.

Flat does not mean 2d. Flat means, in this case, the "thickness" of the universe is so small in relation to the width and length. Like a piece of paper. Paper has a "thickness" like 2mil or .07mil. Some paper is super thin, like tracing paper, and some a bit thicker, like construction paper but its all flat and 3d.

Edits for clarity.

urzu_seven t1_iyd39se wrote on November 30, 2022 at 2:42 PM

That is not at all why the geometry of the universe is described as flat. It has nothing to do with “thickness”

WinBarr86 t1_iyd5s0i wrote on November 30, 2022 at 3:01 PM

I'm trying to keep it simple. But plz do explain. Without explaining like your talking to a scientist who knows alot of the concepts of space/time.

Edit.

But we both know space isn't flat.

Spacetime is not flat. It can't be: Einstein's general theory of relativity says that matter and energy curve spacetime, and there are enough matter and energy lying around to provide for curvature.

WinBarr86 t1_iydcvxm wrote on November 30, 2022 at 3:50 PM

Trying to explain the concept of flat as to curved without using mathematical terms is hard. Flat is a concept, just means non curved. To explain in detail requires a fair bit of knowledge of things like diffent types of geometry and understanding fundamentals of curvatures and Euclidean geometry. Best way to explain flat is paper.