4th dimention ?

[**CQ**]

Hi all, i just joint today so this may sound kinda stuped to you,

if 1D is just one dimention, thad means thad it doesn't exist and we canot do anything with it

if 2D are two dimentions (with and height) it means we can see it, but we can't pick it up (so we can do one thing with it)

if 3D are three dimentions we can do two things with it (we can see it and pick it up)

but if something is 4D doesn't it mean thad we have to be able to see it and pick it up but thad there wil be one ather function thad should be able to be done with it witch we canot understand?

if this it true doesn't it mean thad a 4D object can be anything but we can only see it in 3D?

witch could meen thad ANYTHING like a tree could be a 4D object??

please give your opinion aboute this,

[houserichichi]

Unfortunately you don't measure the "dimension" of something by what you can do with it. The reality of it is the dimension of an object is measured by what you can do "inside" it. One dimension has length only (no height, no thickness). Two dimensions have length and say width. Three dimensions have length, width, and height. A fourth dimension would have another "direction", if you will, associated with it.

A tree obviously exists in three dimensions since we can measure length, width, and height. Does it have any other measurable distances that are disjoint from those three? Unfortunately not so it exists in three dimensions (spatially, of course).

As for the possibility of manipulating a 4d entity in some new way, you have to keep in mind that WE exist in 3d so we are limited in what we are able to do. A 2d "person" is limited in what it can do to us in 3d just as we'd be limited to something in higher dimensional space.

[**CQ**]

but still, we could be living in a 4D (or in a even higher dimension) becouse, do you now what a 3D space is like if all you'v ever know is a
«lets say a 4D space» but you can only move in 3D so, to you'r view point you live in a 3D space wile you are realy living a a 4D space(and i don't care what the 4th dimension is at this point)

[houserichichi]

I see what you're getting at. We very well could be existing in a higher dimensional space, but everything we see and understand requires three dimensions to function and there's no experimental evidence to suggest that there is anything other than what we know yet. So, if we DO exist in a higher dimension we certainly don't know it - in fact we're limited to a three dimensional subspace of 4-space (roughly speaking).

[quickfur]

I see what you're getting at. We very well could be existing in a higher dimensional space, but everything we see and understand requires three dimensions to function and there's no experimental evidence to suggest that there is anything other than what we know yet. So, if we DO exist in a higher dimension we certainly don't know it - in fact we're limited to a three dimensional subspace of 4-space (roughly speaking).

In fact, some people theorize that (the 3D part of) the universe is the realmic surface of an expanding 4D hypersphere. We are, of course, confined to the surface, so there's no way to look into the center of the hypersphere or outwards. Gravity, then, is caused by repulsion of matter from the hyperspheric center (or attraction towards the center, but let's assume the former), and regions of higher mass would experience more net repulsion, causing the realmic surface to bend ala General Relativity.

Of course, this is just speculation, but it does seem rather compelling if refined to fit experimental data better.

[**CQ**]

so, if we live in a (let's say a 4 dimensional) space but all we can understand is a 3 dimensional space, so this means thad we see every thing in 3D no mather in what dimention we live in.

So, (let's just keep it on the tree example) if a tree does have a 4th dimention thad we canot understand we would just see a 'normal'tree (in 3D).


if you think aboute it it is alsow posible thad we, humens, are realy not a object with 3 dimentions, but we can have many more dimentional directions but becouse we can only understand 3 dimentions, our brain yust sets everything in a way we can understand (in 3D)

[collyn]

So if we did have parts of us that did protrude into the forth or a higher dimension, would those parts be unable to sense anything? I would think that they would have to be unable to sense anything. If we had eyes on the part of us that protuded into the forth, we would see something other then what we see normally, right? And if we had some sort of nose, ears, tastebuds, or an organ that could feel (touch), we would proabably end up smelling, hearing, tasting, or feeling some unexplained things, right? I could be wrong here.

I do agree that something like a tree could be able to have some part of them protrude into a forth spatial dimension. For example if a 3-d tree were growing and passed through a 2-d world all that would exist in their world would be a circular cross section of the tree (appearing as a line to them). It would be very real in there world as a tree in our world would be, and they would not be able to tell for sure whether it was truely 2-dimensional or did protrude into other dimensions, just as we can't really tell whether a tree protrudes into a forth dimension. But if we were to shake the tree that passed through that 2-d world, the circular cross section would move, and to any 2-d beings, the movement would appear unexplainable. If something in a 4-d world were to knock into the 4 dimentional protrusions of one of our trees, would it be unexplainable to us how the tree was moved?

[wendy]

I suppose if you looked at the blade-tip of a six-dimensional object, you would see a four-dimensional space. Pretty pointless i should imagine.

The real thing is that you can't "look into" four or two or six dimensions. What you see is an image as if you were in these dimensions. It's not a question of "what does it look like to see into three/four/six dimensions" but how does it feel to be in three or four or six dimensions.

Unlike the real three-dimesnional thing, you have to sort of make it up as you go. There isn't a stretch of terix (4D space) you can sort of "pop into", but something like cultivating holographic vision, and then sort of create the movie as you go along.

Some things look silly, because you may not have the model right, and other things look silly because 4D is different to 3D.