# Four dimensions (split from The meter-second)

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I was wondering what the fourth dimension might be, if a point is 0, a line 1, a square 2, a cube 3 dimensional. What would a 4 dimensional "cube" look like? My thinking went that if a metre cube sat in the same position this could be it. But would that be a cubic metre x second? So I googled metre second and found this link.. so if you know what a four dimensional cube looks like, let me know.

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1 hour ago, nix29 said:

I was wondering what the fourth dimension might be, if a point is 0, a line 1, a square 2, a cube 3 dimensional. What would a 4 dimensional "cube" look like? My thinking went that if a metre cube sat in the same position this could be it. But would that be a cubic metre x second? So I googled metre second and found this link.. so if you know what a four dimensional cube looks like, let me know.

This appears to be completely off-topic. Anyway, replace each of the faces of a cube with cubes (I know, not possible in three dimensions): https://en.m.wikipedia.org/wiki/Tesseract

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Are you looking for a physics definition, such as time in the theory of relativity, or a mathematics definition, such as defining points by number quadruples?

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On 12/15/2017 at 4:03 AM, nix29 said:

I was wondering what the fourth dimension might be, if a point is 0, a line 1, a square 2, a cube 3 dimensional. What would a 4 dimensional "cube" look like? My thinking went that if a metre cube sat in the same position this could be it. But would that be a cubic metre x second? So I googled metre second and found this link.. so if you know what a four dimensional cube looks like, let me know.

It is exactly as you think.

A little deeper into this rabbit hole of "higher dimensions"

Edited by Vmedvil

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A "dimension" just means a number used to specify something of interest.  If I am marking points on a straight line, then I can designate one of those points, arbitrarily, and designate every point by its distance along that line from that point, using positive and negative to specify "left" or "right" of that point.  One number, dimension one.   On a plane there are a whole circle of points at a fixed distance from a fixed point so I would also need to specify a direction- two numbers, dimension two.

Physicists are interested in "events"- what happens at a specific position at a specific time.  It takes three numbers to specify the position and one to specify time.  Therefore "four dimensions".

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There you go, 150 pages on the actual 4-dimensional geometry.

You're welcomed.