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Comment by foolrush | Hacker News Reader

But the fourth dimension is timespace, is it not? At least that was what I gathered from Special and General Relativity and the relativity of simultaneity. X^t, Y^t, Z^t?

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Whatever you decide "the" fourth dimension "is" (what's the first? second? third?), it doesn't stop someone else from imagining a world with an additional spatial dimension. Relativity does imply a close relationship between time and space but the game world doesn't appear relativistic.

I don't think dimensions are specifically numbered. You could call up one dimension, distance along a fixed track another dimension, and distance from the sun your third dimension. You could call temperature your fourth dimension and mass your fifth. This game specifically has 4 spatial dimensions.

When people talk about physics that's what it means. But nothing stops you from making a game with 4 independent axes you can move along.

This game isn't real life! In the game there are four spatial dimensions, just because the game designer decided to have four.

Which is an awful lot like a 4th dimension. Arguably we are all 4th dimensional travellers, albeit somewhat constrained along one of the axes.

Granted, you had me at “This game isn't real life!”

Oh, and the game also has a time dimension (which works normally I think, just one-way at one speed), so I guess that's 5 :)

No, it's actually not. For one, dimensions aren't numbered.

Time is only called "fourth" because we just add it as an extra to the 3 spatial dimensions we perceive intuitively. Not because there's some specific order.

There can be an arbitrary number of special dimensions in mathematics (hence hypercubes, etc).

And according to some (quite prevalent) physics theories, there are actually more than 3 spatial dimensions in the actual reality -- string theory calculations give 10 spatial dimensions.

In a lot of cases, the fourth dimension is describe as space. But if you were looking into string theory, often times there are description of many spatial dimensions, say 11 spatial dimensions and then a single dimension of time.

We could also have multi-dimension time dimensions as well. The idea of parallel universes where at least one decision is made differently from our own could instead be different dimensions of time. Move to the left or right in time and experience different choices as opposed to only going forward as I assume most of us do now. :D

That is one way of numbering dimensions, in a certain model of the universe. However, in a 2d game, time might be a "third dimension". Or time might be sufficiently distinct in some model that it does not behave like a dimension at all.

If I write an equation, and graph it, it has as many dimensions as variables. Those variables might have nothing to do with time OR space.

> But the fourth dimension is timespace, is it not?

No. Only in science fiction novels.

It'd need to be measured in meters to make sense as a real 4th dimension.

What the fourth dimension is depends entirely on what order you put the dimensions in :)

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