Space is only 4D, if you compare 3D along a line with 4D. The space particles may be and should be 3D, since elseways it would change over time.

No, there is a fourth dimension we normally can't see. This is what Einstein found and its the way that gravity works. When our earth travels around the sun, it's moving in a straight line, just as you would imagine a straight line on a piece of paper. However the space that's its traveling on is curved, and thus, the orbit looks curved. You can't curve three dimensional space without a fourth dimension.

]]>What I meant is that we are like a 4D line through 3D rooms, and since everything with dimensions, can change over other dimensions (dy/dx) so that it becomes less dimensional, that will happen and this means that eventually we will reach the end of the line, and then there will only be room, 3D life.

But again, you lose me right off the bat. I don't see how you can see us as a 4d line. Space itself is four dimensional, at the very least. Also, dy/dx is not a change over other dimensions, it how y changes as a function of x.

]]>Anyway, seriously... What I meant is that we are like a 4D line through 3D rooms, and since everything with dimensions, can change over other dimensions (dy/dx) so that it becomes less dimensional, that will happen and this means that eventually we will reach the end of the line, and then there will only be room, 3D life. That is, if it will ever end. That is, if our speed through spacetime is compareable to the length of time. The universe is a box, if you get to the end, you'll have to go sideways. But this I know very little of. Enlighten me if you can.

**How about big bang?**

Yes, but if the room was about to go 2D, wouldn't it start like that?

How is it that something can go 2D?

]]>And thanks for the neat paper width examination. You have alot of them, don't you?

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