[Titanscape (OP)]

We know what the first four are... Linear then two dimensions, the third, volume, the fourth, volume moving in time in a linear time motion. But what is the fifth dimesion physicists suggest exists?

Can something move sideways in time?

Titanscape

[another_someone]

quote:Originally posted by Titanscape

We know what the first four are... Linear then two dimensions, the third, volume, the fourth, volume moving in time in a linear time motion. But what is the fifth dimesion physicists suggest exists?

Can something move sideways in time?

Titanscape

Some physicists talk about as many as 11 dimensions, but 7 of them being collapsed into minute sizes, but I will not even attempt to comprehend the mathematics behind it all.

[johndiver]

Perhaps the answer would be more apparent if you changed the wording of your question from "the fifth dimension" to "a fifth dimension".
Simply stated, it is another direction of motion that is possible, allowing a 5-dimensional being to move around an object that stops a 3-dimensional person.
Extra dimensions almost certainly exist, but have not yet been "seen" or proven by experiment.
As mentioned in a previous post, physicists studying string theory have found mathematical suggestion of 11 dimensions. Some research is being done to find them by inspecting gravitational attraction between atoms to find any exceptions to the law of Gravity.
There is an excellent  book which I have not read called "Flatlander" which you may enjoy.

[Solvay_1927]

As far as I recall, of these 11 dimensions (which string theory needs to satisfy its mathematical requirements), only 1 of them is a time dimension, and the other 10 are all space dimensions (of which, as mentioned above, 7 are curled up so small as to be undetectable).

I've heard that there are other theories that require different numbers of dimensions (e.g. 26 dimensions in another version of string theory), but they still always only require 1 time dimension.

But these are all just theories - and I imagine that you could (if you really wanted to) come up with a new theory that uses 2 or more time dimensions. But I get the impression that such a theory wouldn't be very fruitful.  (Or maybe it's just that nobody's ever tried such a theory yet??)


"Eagles may soar, but weasels don't get sucked into jet engines."

[johndiver]

"Can something move sideways in time?"

Can something move sideways along a string?
What would one be doing if they could move sideways in time anyhow?

[another_someone]

quote:Originally posted by johndiver

"Can something move sideways in time?"

Can something move sideways along a string?
What would one be doing if they could move sideways in time anyhow?

One cannot move 'sideways' in one dimension.  A sideways motion implies two dimensions, and which dimension is regarded as 'sideways' motion is an arbitrary judgement of the observer.

[stinkinstudentlamo]

I think it would be impossible for us to actually percieve or experience a dimension other than our own (possibly excluding time) since we are in our own "3rd Dimension"

Reasoning behind this would be that it is impossible for a person living in a one dimensioanl land to percieve something living in 2 dimensions and someone living in 2 dimensions to perceive three dimensions etc

[another_someone]

quote:Originally posted by stinkinstudentlamo
Reasoning behind this would be that it is impossible for a person living in a one dimensioanl land to percieve something living in 2 dimensions and someone living in 2 dimensions to perceive three dimensions etc

It is impossible to know what is happening in the other dimension, but it would be incorrect to say we cannot perceive the object itself, but we would only perceive one of its two dimensions.  As a two dimensional object were to pass through our one dimension (assuming we also had the dimension of time as well as our one/two physical dimensions), we would merely perceive it as getting bigger and smaller within our own dimension.  From this, we may speculate about the existence of the other dimension, or merely accept that the size of this object within our universe changes over time.  We would not be able to distinguish one scenario from another.

[Solvay_1927]

You might not have to have contact with a higher-dimensional object to realise that there are higher dimensions.

Consider a flatlander living in a 2-dimensional sheet - but this sheet is (to us 3-D observers) actually a spherical shell (a large spherical shell, with a huge radius, say).

Say the flatlander draws a small triangle. They walk around it and work out that its internal angles must add up to (almost exactly) 180 degrees.

But then they draw a huge triangle which covers an eighth of the surface of the shell (say, starting at their "north pole" and drawing a line to the "equator", then turn right and go a quarter of the way around the equator, then turn right again and end up back at the north pole).  And they realise that the internal angles must add up to 270 degrees! (This triangle contains a right angle at each of its corners.)

To explain this the flatlanders might come up with some weird theory about lengths and angles changing the further away they are. But the clever ones among them will realise that their two-dimensional space can just be considered as a curved, closed sheet embedded in a higher (3-D) world.

So they realise that there ARE higher dimensions (and they can even come up with ways of measuring how curved their 2-D space is in this 3-D universe), even though they can't see anything outside their 2-D space.


"Eagles may soar, but weasels don't get sucked into jet engines."

[another_someone]

quote:Originally posted by Solvay_1927

You might not have to have contact with a higher-dimensional object to realise that there are higher dimensions.

Consider a flatlander living in a 2-dimensional sheet - but this sheet is (to us 3-D observers) actually a spherical shell (a large spherical shell, with a huge radius, say).

Say the flatlander draws a small triangle. They walk around it and work out that its internal angles must add up to (almost exactly) 180 degrees.

But then they draw a huge triangle which covers an eighth of the surface of the shell (say, starting at their "north pole" and drawing a line to the "equator", then turn right and go a quarter of the way around the equator, then turn right again and end up back at the north pole).  And they realise that the internal angles must add up to 270 degrees! (This triangle contains a right angle at each of its corners.)

To explain this the flatlanders might come up with some weird theory about lengths and angles changing the further away they are. But the clever ones among them will realise that their two-dimensional space can just be considered as a curved, closed sheet embedded in a higher (3-D) world.

So they realise that there ARE higher dimensions (and they can even come up with ways of measuring how curved their 2-D space is in this 3-D universe), even though they can't see anything outside their 2-D space.


"Eagles may soar, but weasels don't get sucked into jet engines."

Are you not confusing the curvature of a surface with an assumption that there are further dimensions.  This is fine if you arbitrarily assume that Euclidean space is paramount, but if you believe that non-Euclidean spaces may naturally exist, then is it reasonable to extrapolate from the notion of curved space to the notion of higher dimensions?

Is not the premise of General Relativity that space is naturally curved, and it does not do this by suggesting that there are more dimensions than the four we are aware of (the additional dimensions originate from String theory, not from General Relativity).

[stinkinstudentlamo]

Could we not say that for a certain dimension to exist, it follows that their needs to be a higher dimension for that dimension to exist in? There could be an infinite number of dimensions! interesting concept

I refuse to answer that question on the grounds that I don't know the answer.
-- Douglas Adams

[another_someone]

quote:Originally posted by stinkinstudentlamo

Could we not say that for a certain dimension to exist, it follows that their needs to be a higher dimension for that dimension to exist in? There could be an infinite number of dimensions! interesting concept

I refuse to answer that question on the grounds that I don't know the answer.
-- Douglas Adams

I would be tempted to agree with Douglas Adams in this case.[]

I suppose I would start by asking what is meant by the existence of a dimension?  One might say the fact that a dimension is a conceptual thing, that you may conceptualise an infinite number of dimensions, it means that you have brought into existence an infinite number of dimensions.  To the extent that a dimension might be considered to have a physical existence, one must ask which of those dimensions could interact or influence the physical world?

[Solvay_1927]

quote:Are you not confusing the curvature of a surface with an assumption that there are further dimensions.

Yes, admittedly I am.  My example wouldn't constitute absolute proof (to the flatlanders) that a higher dimension exists - but they would definitely see it as a simple, plausible explanation of what's going on.

I imagine that any "evidence" of a higher dimension could alternatively be explained using some other theories - but the simplest theory would surely be that there are higher dimensions, wouldn't it?


"Eagles may soar, but weasels don't get sucked into jet engines."

[Solvay_1927]

Many years ago, an (ex-) girlfriend described me as "two-dimensional".

At first I thought she was expounding some sort of theory about our perceptions of the universe.

But then I realised what she was saying!  [!]

"Eagles may soar, but weasels don't get sucked into jet engines."

[another_someone]

quote:Originally posted by Solvay_1927

quote:Are you not confusing the curvature of a surface with an assumption that there are further dimensions.

Yes, admittedly I am.  My example wouldn't constitute absolute proof (to the flatlanders) that a higher dimension exists - but they would definitely see it as a simple, plausible explanation of what's going on.

I imagine that any "evidence" of a higher dimension could alternatively be explained using some other theories - but the simplest theory would surely be that there are higher dimensions, wouldn't it?

"Eagles may soar, but weasels don't get sucked into jet engines."

Simpler theory, or merely the more familiar theory?

If Euclid had never formulated his view of three dimensional space, and we had not grown up with the notion of this being the 'normal' way of looking at the universe, then what would be the simpler theory, to merely accept the complexity of having strange triangles (but not really that strange, because we'd all be so used to them that they would seem natural), or to postulate some other dimensions that none of us had ever experienced?

[another_someone]

quote:Originally posted by Solvay_1927

You might not have to have contact with a higher-dimensional object to realise that there are higher dimensions.

Consider a flatlander living in a 2-dimensional sheet - but this sheet is (to us 3-D observers) actually a spherical shell (a large spherical shell, with a huge radius, say).

Say the flatlander draws a small triangle. They walk around it and work out that its internal angles must add up to (almost exactly) 180 degrees.

But then they draw a huge triangle which covers an eighth of the surface of the shell (say, starting at their "north pole" and drawing a line to the "equator", then turn right and go a quarter of the way around the equator, then turn right again and end up back at the north pole).  And they realise that the internal angles must add up to 270 degrees! (This triangle contains a right angle at each of its corners.)

To explain this the flatlanders might come up with some weird theory about lengths and angles changing the further away they are. But the clever ones among them will realise that their two-dimensional space can just be considered as a curved, closed sheet embedded in a higher (3-D) world.

So they realise that there ARE higher dimensions (and they can even come up with ways of measuring how curved their 2-D space is in this 3-D universe), even though they can't see anything outside their 2-D space.

"Eagles may soar, but weasels don't get sucked into jet engines."

Thinking a little more about this.

I do not think your answer above is the right answer, for reasons I have already suggested, but I think there might be a way to gain evidence of additional dimensions.

Suppose that, in a two dimensional world, we were to see some event occur, and a few nanoseconds later, we see a corresponding event some few thousand miles away.  This happens repeatedly, and there is no link within our universe between the two points where we see synchronised events occurring, but the pattern is too regular to believe they are mere coincidence.  We might then postulate that there is a link that exists outside of dimensions that are visible to us that link those disparate points, and this might lead us to consider an additional dimension to the universe.

This, I think, is related to what some quantum physicists are speculating upon with regard to wormholes within our own universe.

[stinkinstudentlamo]

think you might have a point there another_someone.

this would explain how it is signals can 'apparently' be sent faster than light - which is ordinarily impossible.

This dimension that would connect the two points could be bent or curved in someway to allow this to happen.

I refuse to answer that question on the grounds that I don't know the answer.
-- Douglas Adams

[Solvay_1927]

I agree with all your comments, someone & stinkin.

But what I’m suggesting is that you can’t really PROVE there’s a higher dimension – that’s just one of several alternative explanations for such phenomena.  The phenomena you mention, someone, could be explained by FTL signalling.  And why should FTL be any less plausible than proposing higher dimensions?

Going off at a tangent slightly . . . I've just realised that I don't understand why Einstein’s theories of relativity forbid FTL signalling.
Relativity says you can’t accelerate an object (which has mass) up to c.  But it doesn’t mean that objects can’t exist which are already travelling at a speed HIGHER than c (or so I’ve read).
(Of course, the ones travelling at >c could never be decelerated to c or below, according to the theory.)

Is FTL signalling impossible because these two types of objects (>c and <c) could never interact with each other?

(The more I learn about relativity, the more I realise I don’t understand it. [])
Solvay.


"Eagles may soar, but weasels don't get sucked into jet engines."

[another_someone]

quote:Originally posted by Solvay_1927

I agree with all your comments, someone & stinkin.

But what I’m suggesting is that you can’t really PROVE there’s a higher dimension – that’s just one of several alternative explanations for such phenomena.  The phenomena you mention, someone, could be explained by FTL signalling.  And why should FTL be any less plausible than proposing higher dimensions?

There is a difference.

If you have something that occurs at point A, and something happens shortly afterwards at point B, if the events are linked by a particle travelling between point A and point B within our universe, then you should be able to intercept that particle at a midway point between A and B.  If the particle is travelling in a dimension outside of our experiential universe, then it would be impossible to intercept the particle at a midway point.

I accept that there are caveats to the above statement.  While the distinction may be true, it may not necessarily be that easy to implement the intercept, but it must inevitably be somehow possible.  If it is impossible to intercept the particle, then it can only be because the particle is not there (within out experiential universe).

Incidentally, the principle is not necessarily about distinguishing FTL paths, it may be that the travel through the other dimension may even be a longer path, but the general principle is that the distinction is whether or not the particle exists within our experiential universe at all points along its path.

quote:
Going off at a tangent slightly . . . I've just realised that I don't understand why Einstein’s theories of relativity forbid FTL signalling.
Relativity says you can’t accelerate an object (which has mass) up to c.  But it doesn’t mean that objects can’t exist which are already travelling at a speed HIGHER than c (or so I’ve read).
(Of course, the ones travelling at >c could never be decelerated to c or below, according to the theory.)

Is FTL signalling impossible because these two types of objects (>c and <c) could never interact with each other?

(The more I learn about relativity, the more I realise I don’t understand it. [])
Solvay.

"Eagles may soar, but weasels don't get sucked into jet engines."

I think that is the whole point.  I probably know no more than you about relativity, but I had always assumed that it was simply the inability to interact, and that which cannot interact with you, for all practical purposes, is not there.

Within a black hole, matter will be travelling faster than light, but it cannot escape the black hole, and so we cannot interact with it.

The point is, what would happen is something that is faster than light were to hit something that is slower than light – if the two were to interact, then (at least in classical physics, and relativity is a part of classical physics, not quantum physics), the two particles must momentarily be at the same speed, before exchanging momentum and bouncing off each other.  Thus, in the classical world, the two cannot interact without one or the other momentarily crossing the light speed boundary (at least, that is my naïve interpretation).

[A Big Mug]

I have often wondered if the simple action of a gyroscope would eventually prove the existance of other dimensions.  Inertia and momentum seem like they need to be explained better.  Higgs fields could be generated in a higher dimension.