Understanding Dimensions

Originally posted by MrAtomicspace
Don't confuse the two because the word quantum is used.

You, not I, confused them.

Dimension is not a direction. When you talk of 2D space, you can specify a point A(x,y), in this case it is taking the meaning of 'space' not direction. If you considered the distance from point A to point B, this would show direction, (i.e. vector quantity). But generally speaking, dimensions are just a 'space'.

You are wrong. Now please stop wasting everybody's time.

reply to post by Astyanax

You are wrong

Well If you say that I am wrong, you surely must have some evidence to support your claim?

Theoretically, the dimension of time is not a prerequisite to seeing 3-dimensions in a 3D universe. That "4D" of time is only needed to see change. However, you do need 2 eyes or inputs to "see" the third dimension in a 3D universe.

In reality though, in any spatial universe, you would always need the dimension of time in order to see anything because without time, photons of light don't move, your eyes can't see, and your brain can't think, and life can't exist. Without time, the universe is frozen.

The dimension of time is independent of the spatial dimensions. For example, you could have a 1D universe with the dimension of time.

reply to post by harrytuttle


I see what you mean, and I agree with your concept. Does this mean 4th dimension is not time?

reply to post by MrAtomicspace

Yes, that's what I mean. There is no "4th" spatial dimension (that we can observe anyways). Space (3D) and time are interwoven into the space-time continuum. Time can't exist without space, and space can't exist without time.

Originally posted by harrytuttle
Theoretically, the dimension of time is not a prerequisite to seeing 3-dimensions in a 3D universe. That "4D" of time is only needed to see change. However, you do need 2 eyes or inputs to "see" the third dimension in a 3D universe.

In reality though, in any spatial universe, you would always need the dimension of time in order to see anything because without time, photons of light don't move, your eyes can't see, and your brain can't think, and life can't exist. Without time, the universe is frozen.

The dimension of time is independent of the spatial dimensions. For example, you could have a 1D universe with the dimension of time.

edit on 11-10-2010 by harrytuttle because: correction

This.

To the thread in general I would like to add that if a four-dimensional being were looking at us, it could see all our guts on display all at once. There would be no hiding anything from a four-dimensional being.

To understand this, if you were a two dimensional being living on a two dimensional plane, and looking at, say, a circle, you would of course only see its boundary, but nothing inside of it. But we, a three-dimensional being looking onto that plane, can see everything inside the circle.

Thus it's reasonable to assume a four-dimensional being (if such a thing is possible beyond mere imagination) would be able to see us and everything inside us with just as much ease.

Originally posted by NewlyAwakened

Originally posted by harrytuttle
Theoretically, the dimension of time is not a prerequisite to seeing 3-dimensions in a 3D universe. That "4D" of time is only needed to see change. However, you do need 2 eyes or inputs to "see" the third dimension in a 3D universe.

In reality though, in any spatial universe, you would always need the dimension of time in order to see anything because without time, photons of light don't move, your eyes can't see, and your brain can't think, and life can't exist. Without time, the universe is frozen.

The dimension of time is independent of the spatial dimensions. For example, you could have a 1D universe with the dimension of time.

edit on 11-10-2010 by harrytuttle because: correction

This.

To the thread in general I would like to add that if a four-dimensional being were looking at us, it could see all our guts on display all at once. There would be no hiding anything from a four-dimensional being.

To understand this, if you were a two dimensional being living on a two dimensional plane, and looking at, say, a circle, you would of course only see its boundary, but nothing inside of it. But we, a three-dimensional being looking onto that plane, can see everything inside the circle.

Thus it's reasonable to assume a four-dimensional being (if such a thing is possible beyond mere imagination) would be able to see us and everything inside us with just as much ease.

This is incorrect. The logic is faulty.

In your 2d example, you are saying that a 2d being looking at a 3d construct would only be able to see parts of the 3d construct which intersected the 2d plane the being was on. This is a lower dimensional being looking upwards.

To have a higher dimensional being looking downwards you would need to reverse your analogy. It would be just like you or I looking at a 2d drawing. We see no guts on display.

Originally posted by bigfatfurrytexan
This is incorrect. The logic is faulty.

In your 2d example, you are saying that a 2d being looking at a 3d construct would only be able to see parts of the 3d construct which intersected the 2d plane the being was on. This is a lower dimensional being looking upwards.

To have a higher dimensional being looking downwards you would need to reverse your analogy. It would be just like you or I looking at a 2d drawing. We see no guts on display.

I spoke only of a higher dimensional being looking downward, but you are correct that the lower dimensional being could only see the parts of a higher dimensional being that intersected the lower's space (and in fact only the yet-another-dimension-lower surface of that cross-section, assuming it is not transparent).

As for no guts being on display in a picture, the reason for this is mundane: A 2D drawing intended for viewing by humans is still intended to represent a 3D object as it would look to a 3D creature viewing it. Thus you are of course only drawing the surface.

But imagine if there were literally a 2D creature inhabiting some 2D plane. Its boundary between inside and outside would be a one-dimensional curve (bending of course in 2D space), just as the boundary of a 3D object is a two-dimensional surface (bending in 3D space). Its innards would be inside of this boundary. Then imagine a 3D creature such as ourselves has some way of viewing a "map" of the 2D world. We would not have the limitations of in-worlders of only seeing the boundaries of other objects in the world; we would see the boundaries and everything inside and out.

Obviously all this stuff is totally fantastical.

reply to post by NewlyAwakened

A star for correctness and clarity, but

To the thread in general I would like to add that if a four-dimensional being were looking at us, it could see all our guts on display all at once. There would be no hiding anything from a four-dimensional being.

Right if the fourth dimension is spatial. Not if you're regarding time as the fourth dimension. In that case you'd see the usual 3D rat or Paris Hilton, but you'd see them from the moment of conception to that of dissolution, all at once.

But imagine if there were literally a 2D creature inhabiting some 2D plane. Its boundary between inside and outside would be a one-dimensional curve (bending of course in 2D space), just as the boundary of a 3D object is a two-dimensional surface (bending in 3D space). Its innards would be inside of this boundary.

Yep. |A Brief History of Time has a picture of a 3D dog separated into two parts by his alimentary canal.

Dammit, I hate giving out so many stars.

reply to post by NewlyAwakened

But we, a three-dimensional being looking onto that plane, can see everything inside the circle.

I don't agree with your concept. What do you mean by "can see everything inside the circle"? I am suggesting that a sphere/circle looks like a line for a 2D being. Furthermore, in the today's world of science (20th-21st century), it is widely acknowledged that the 4th dimension is time, also accepted by Einstein. I see your concept as logically wrong, but that's just me. Maybe I have not understood you well..

reply to post by Astyanax

I was of course referring to spatial dimensions; the quote in my first post was because he mentioned time not being the same sort of thing as the spatial dimensions.

I've always wanted to read that book; I ought to pick it up someday.

Originally posted by MrAtomicspace
I don't agree with your concept. What do you mean by "can see everything inside the circle"? I am suggesting that a sphere/circle looks like a line for a 2D being. Furthermore, in the today's world of science (20th-21st century), it is widely acknowledged that the 4th dimension is time, also accepted by Einstein. I see your concept as logically wrong, but that's just me. Maybe I have not understood you well..

I would agree with your last sentence. This stuff is hard to wrap your head around.

I don't really care to what people apply the words "fourth dimension". I am speaking of the abstract (but mathematically sound) idea of a fourth spatial dimension. In such a world you are welcome to call time a fifth dimension if it floats your boat, but my meanderings were not really about time so this would just be extraneous information.

The sphere/circle does look like a line to a 2D being (perhaps with some form of depth perspective added). But to a 3D being, a circle looks like a circle. You can see its innards. That's my whole point.

It's of course very hard (well, impossible) to visualize four spatial dimensions. I would recommend the book someone else recommended early in the thread, "Flatland"; it's great for wrapping your mind around this stuff.

reply to post by NewlyAwakened


www.fisica.net...

I assume that the word "Brief" in the title refers to the length of the book? The linked .pdf is only 101 pages.

reply to post by NewlyAwakened

I am speaking of the abstract (but mathematically sound) idea of a fourth spatial dimension.

I now see what you are talking about; according to mathematical point of view, there are infinite spatial dimensions (hyperspaces).

Thanks for this. My alien encounter was possibly due to a leakage in our dimension and theirs.