3D existence in a 4D world

[FortySIXandTWO]

I've been thinking about a 4D being's ability to manipulate 3D. I was thinking that it would be possible for a 4D being to pick up an object from 3D, pull it into 4D and then put it anywhere it wanted in 3D. It would explain where all my socks go in the laundry. If it were possible for this to occur than a 4D being could bring a 3D being into the fourth dimension. I was wondering if it were possible for a 3D being to exist in a 4D universe or if the lack of heat, light, and air cause him/her to expire. If not, what would the 3D being be able to see in a 4D universe? With a 2D retina I should imagine that he would see a flat representation of 4D objects much like a hypercube. Then again, what kind of objects would be in a 4D universe? Super advanced modes of transportation, buildings and staircases would be pretty trippy. Possibly like an M.C. Escher drawing. But, I digress.
So, can a 3D person exist in a 4D world? What would the 3D person see?

[Hugh]

What would the 3D person see?

This has been a question I've pondered for years. I think we'd see a hypercube room as a surrounding cube - a 3d slice of it. There are other thoughts I've already had about this, but instead of repeating them I'll just refer you to the Visual Reorientation Illusion thread. http://tetraspace.alkaline.org/forum/viewtopic.php?t=401

[Nick]

I think they would be able to live. Imagine you pulled a 2d person into the 3d world; you would be quick to assume that his insides would fall onto the floor because of the new source of gravity. But, if you are able to reach into his world to begin with, then gravity must also be able to reach into his world; therefore, 3d gravity would always have had an effect on him.

As long as you keep him straight up and down, he should be able to live; maybe not move, seeing as how his legs cannot bend three dimensionally (unless you make them bend that way.. heh heh heh :twisted:).

Also, using the same example, the guy would only see a 1 dimensionally line for everything. But I don't think he would get tripped up; instead of seeing cubes, he sees squares and trapezoids; instead of seeing spheres, he sees circle, etc. M.C. Echer was just wierd...

It would explain where all my socks go in the laundry.

Oh ! No wonder! :wink:

[The_Science_Guy]

"...M.C. Escher drawing...." Is that the one with all those staircases? :?

[Hugh]

"...M.C. Escher drawing...." Is that the one with all those staircases? :?

Here is one of his staircase drawings:



Fascinating to look at, but I don't think it is an accurate representation of what we would see in 4d, nor was it meant to be.

[darthbadass]

Fry (in Futurama, looking at an apartment like that painting): I'm not sure I want to pay for a dimension we're not going to use...

[thigle]

this picture of Escher is called Gravity and it was conostructed over 3 vanishing points that lie far beyond the frame of the picture plane. the actual execution of the print was over 3x3m, even though the picture itself was less than 0.5m^2.

it plays on the idea of local/global orientability/nonorientability. there are 3 gravity fields, each one in a prependicualr relation to others and they interpenetrate.

[Hugh]

this picture of Escher is called Gravity

I think it's called Relativity...

[The_Science_Guy]

"...M.C. Escher drawing...." Is that the one with all those staircases? :?

Here is one of his staircase drawings:



Fascinating to look at, but I don't think it is an accurate representation of what we would see in 4d, nor was it meant to be.

Thank you, that picture is exactly what I thought you were talking about!

[thigle]

hugh, you prolly right, i didnt check it in the book and that's how it was in my memory. but relativity of gravity was meant perhaps. or almost surely.

[Hugh]

I think this is Escher's Gravity:

Anyways, "Relativity" is an interesting play on gravity. If you plug in "relativity" and "escher" into google images, you get all kinds of representations of that staircase image. Even 3d models built in lego!

Btw, I've found that imageshack is a great free image hosting service.

[mjjirachi]

Is it actually possible in the first place for a 2d being to exist in a 3d world?

[Nick]

Is it actually possible in the first place for a 2d being to exist in a 3d world?

Well, gravity wouldn't affect him, and any substances and gasses that he has already been exposed to wouldn't affect him, so I can conclude that he would be so long as he stays within the same area that his 2d world is in.

[moonlord]

In principle yes, but we still argue on how would it interact with the 3D world around him.

[PWrong]

Is it actually possible in the first place for a 2d being to exist in a 3d world?

I guess it depends which 3D world you mean. If it's our 3D universe, then it's probably not possible. If it's not our universe, then it might be a 3D universe where 2D beings exist.

That said, everything in our universe is supposed to be made of 1D strings anyway.

[mjjirachi]

Is it actually possible in the first place for a 2d being to exist in a 3d world?

I guess it depends which 3D world you mean. If it's our 3D universe, then it's probably not possible. If it's not our universe, then it might be a 3D universe where 2D beings exist.

That said, everything in our universe is supposed to be made of 1D strings anyway.

If 1d strings only have depth and not width, then how can they be stacked to make 2d, and eventually 3d, shapes anyway?

[Nick]

Is it actually possible in the first place for a 2d being to exist in a 3d world?

I guess it depends which 3D world you mean. If it's our 3D universe, then it's probably not possible. If it's not our universe, then it might be a 3D universe where 2D beings exist.

That said, everything in our universe is supposed to be made of 1D strings anyway.

If 1d strings only have depth and not width, then how can they be stacked to make 2d, and eventually 3d, shapes anyway?

Uhhh... you put one on top of the other?

[mjjirachi]

yes, but they are infinitly thin, they wouldnt make any kind of mass apart from a line which is what you started with.

[Nick]

Anything infintessimal + anything greater zero = something with volume -> mass is gained.

[PWrong]

You don't stack strings on top of each other, you combine them the way you combine electrons and quarks to make atoms. An electron is a single string. It doesn't need volume to have a mass.

[moonlord]

Besides, we yet don't know what mass is. The smaller we get we find out that most mass is in fact kinetic energy... So is there a fundamental mass or is it just "nothing" moving at high speed?