What is the true nature of time?

[TheAlkemist]

I'd like to hear how you determine the "distance" between to widely separated events in space and time that is invariant when observed from different frames of reference. In other words, how do you address the issue that "spacetime interval" addresses?

u realize that implicit in ur question is the notion of measuring time as a distance? besides, spacetime interval addresses an issue created by the conception of space and time as a single entity. it's like a custom designed solution.
My short answer to ur question is that it's irrational and conceptually impossible to measure space (emptiness) between objects. U measure the physical object in space. But i'll leave it here. I'm not changing any minds in here anyway. and I'm not trying to offend anyone. just commenting.

 

[TheAlkemist]

No. There are several cases where it introduces confusion in beginning students, but not self-contradiction. That is the whole point of establishing a unified mathematical framework for a theory.

Ok.

"The term 4-D means that it takes 3 spatial coordinates and 1 temporal coordinate to specify the position of a point or event.

"An object is said to have as many dimensions as there are axes required to locate its position in space"

Are both definitions above correct?

Making accurate predictions about the results of experiments is the only scientific criteria. Other criteria amount philosophical or personal preference.

Ok. ur right.

 

[ghwellsjr]

u realize that implicit in ur question is the notion of measuring time as a distance?

That's why I put "distance" in quotes, so that you would not take exception to my terminology because I can't tell what terminology you prefer.

besides, spacetime interval addresses an issue created by the conception of space and time as a single entity. it's like a custom designed solution.

Spacetime does not create the issue, nature does, and spacetime interval is a solution.

My short answer to ur question is that it's irrational and conceptually impossible to measure space (emptiness) between objects. U measure the physical object in space. But i'll leave it here. I'm not changing any minds in here anyway. and I'm not trying to offend anyone. just commenting.

But you said you could solve the same problem that "spacetime interval" solves except by another method. Now are you telling me that you don't believe there is any solution?

Let's take, for example, the first half of the twin paradox. The twins (or two identical clocks) start out at the same age (or set to the same time) at the same location. One of them accelerates away and travels at a high speed for awhile and then decelerates and comes to rest with respect to the first twin (or clock) some distance away. This defines two events: the first is when the traveler starts out and the second is when the traveler stops. When this situation is analyzed from different frames of reference, different answers will be determined for the actual physical distance the traveler traversed and for the actual physical time that it took the traveler to make the trip. Do you agree? If yes, then how do you reconcile the different measurements of distance and time? If no, then please explain why.

 

[cshum00]

OK, then why u can't have just tag on, say, temperature, and static charge yo x,y,z,t and call it 5D?

You can as long as it is mathematically useful. Physical "spacial dimension" only has 3 dimensions x,y,z. Time is a dimension but not a spatial dimension. Because Special Relativity uses both spatial dimension and time dimension then we combine them so that it is mathematically useful and we call it "space-time dimension".

I am just saying that you were not defining dimension abstractly enough but you are rather defining spatial dimension in specific instead.

 

[Phrak]

Ur right, temperature, pressure and attitude have nothing to do with shape. As for spacetime, this interval u speak of is simply a number-line that's been added as an extra "time dimension". A metric for duration so to speak. The purpose of adding this is to endow the model with Lorentz symmetry right? Is this in anyway related to the concept of T-symmetry? If so, isn't the the physical universe we observe time asymmetric (because of 2nd Law of thermodynamics?).
Hope I'm not way off here...

As in space alone, there is no preferred direction in spacetime that you can call the time direction. In this regard they are inseparable, unlike space+temperature, say. A Lorentz symmetry is more of a rotational symmetry, similar to rotating spatial vector.

 

[DaveC426913]

As in space alone, there is no preferred direction in spacetime that you can call the time direction. In this regard they are inseparable, unlike space+temperature, say. A Lorentz symmetry is more of a rotational symmetry, similar to rotating spatial vector.

I could be misunderstanding you but the time dimension is different from the other spatial dimensions; it is "timelike", whereas the others are "spacelike". At least one defining distinction between the two is that timelike dimension(s) only permit movement in one direction.

 

[Dale]

"The term 4-D means that it takes 3 spatial coordinates and 1 temporal coordinate to specify the position of a point or event.

"An object is said to have as many dimensions as there are axes required to locate its position in space"

Are both definitions above correct?

The first is basically correct, although I would have been more specific (e.g. "The term 4-D spacetime"). The second is not correct, it seems to be describing the dimensionality of a space and not the dimensionality of an object as it says.

 

[Phrak]

I could be misunderstanding you but the time dimension is different from the other spatial dimensions; it is "timelike", whereas the others are "spacelike".

It was in my opinion that to throw in that sort of detail would cloud the issue at the level of understanding of the question. However I didn't make my case very well, did I?

To try again: <We cannot pick-out anyone direction in spacetime and say "this is the time direction". Observers in relative motion will not agree. In this regard space and time are inseparable.> How's that?

At least one defining distinction between the two is that timelike dimension(s) only permit movement in one direction.

I don't know what the meaning of movement in time is. However, world lines of classical and incoherent particles are confined to the interior of the light cone.

To be really abstract, the difference is that rotations in space have a real valued parameter of rotation, whereas rotations between space and time have an equivalent imaginary parameter. But this doesn't really tell us what class of objects must have their world lines confined to the interior of the light cone... hmm...

 

[ghwellsjr]

My short answer to ur question is that it's irrational and conceptually impossible to measure space (emptiness) between objects. U measure the physical object in space.

I hope you realize that the issue we are talking about isn't confined to distances between objects in empty space, the same issue exists between the shape of a single physical solid object on the surface of good old earth. The Michelson-Morley experiment is what started this whole thing. It was a single very large, very solid, very massive object that seemed to be changing its dimensions simply by being rotated. How do you understand Lorentz contraction when applied to MMX?

 

[Phrak]

The Michelson-Morley experiment is what started this whole thing. It was a single very large, very solid, very massive object that seemed to be changing its dimensions simply by being rotated. How do you understand Lorentz contraction when applied to MMX?

I'm not sure what you are attempting to infer, but the Michelson Morley experiment yielded null results. They measured no difference in dimensions, or anything else.

 

[ghwellsjr]

MMX was the inspiration for Lorentz to explain the null result by saying that the physical dimension of the apparatus was contracted along the direction of the aether wind. Michelson, on the other hand, believed that he could not measure the aether wind because he thought the Earth was dragging the aether along with it.

 

[John232]

I don't think even the best physicst can explain exactly why time is a dimension. The best explanation I have read in any book written by one is that if they where to point out on a map the exact coordinates where you will meet them you would never be able to meet them there without knowing when they will be there. Then the time coordinate allows your meeting.

 

[Dale]

I don't think even the best physicst can explain exactly why time is a dimension. The best explanation I have read in any book written by one is that if they where to point out on a map the exact coordinates where you will meet them you would never be able to meet them there without knowing when they will be there. Then the time coordinate allows your meeting.

Seems like even amateur physicists can explain exactly why time is a dimension.

 

[TheAlkemist]

That's why I put "distance" in quotes, so that you would not take exception to my terminology because I can't tell what terminology you prefer.

Spacetime does not create the issue, nature does, and spacetime interval is a solution.

But you said you could solve the same problem that "spacetime interval" solves except by another method. Now are you telling me that you don't believe there is any solution?

Let's take, for example, the first half of the twin paradox. The twins (or two identical clocks) start out at the same age (or set to the same time) at the same location. One of them accelerates away and travels at a high speed for awhile and then decelerates and comes to rest with respect to the first twin (or clock) some distance away. This defines two events: the first is when the traveler starts out and the second is when the traveler stops. When this situation is analyzed from different frames of reference,different answers will be determined for the actual physical distance the traveler traversed and for the actual physical time that it took the traveler to make the trip. Do you agree? If yes, then how do you reconcile the different measurements of distance and time? If no, then please explain why.

No. I believe there's a fundamental error in the relativist's notion of distance. What's actually being measured as "distance" is actually "distance traveled". hence why "distance" is defined in terms of c. Relativity alludes to the qualitative static distance (between two objects or "events") but explains the theory with respect to dynamic distance traveled. Case in point is the phenomenon of "length contraction".
If I'm standing 20 yards away from a tree (where there's a measuring device) and a muon zips past me at near the speed of light, relativity theory says that the distance between the muon an the tree contracts. Now did the static distance between me and the tree shrink or was it the distance between the muon and the tree? And if the answer is the later, then say there's a rock between me and the tree, did the distance between the rock and tree also shrink?

You can as long as it is mathematically useful. Physical "spacial dimension" only has 3 dimensions x,y,z. Time is a dimension but not a spatial dimension. Because Special Relativity uses both spatial dimension and time dimension then we combine them so that it is mathematically useful and we call it "space-time dimension".

I am just saying that you were not defining dimension abstractly enough but you are rather defining spatial dimension in specific instead.

As far as I'm concerned, time is not a dimension. it's simply a number line. it's then endowed with orthogonality and combined with the 3 "spatial" dimensions. as such mathematicians have simply just created, lie u said, a useful framework for modeling the physics of objects in space.

As in space alone, there is no preferred direction in spacetime that you can call the time direction. In this regard they are inseparable, unlike space+temperature, say. A Lorentz symmetry is more of a rotational symmetry, similar to rotating spatial vector.

So what's the preferred direction of temperature?

I hope you realize that the issue we are talking about isn't confined to distances between objects in empty space, the same issue exists between the shape of a single physical solid object on the surface of good old earth. The Michelson-Morley experiment is what started this whole thing. It was a single very large, very solid, very massive object that seemed to be changing its dimensions simply by being rotated. How do you understand Lorentz contraction when applied to MMX?

I understand it as an indirect inference from a null-experiment.

 

[Mentz114]

No. I believe there's a fundamental error in the relativist's notion of distance. What's actually being measured as "distance" is actually "distance traveled". hence why "distance" is defined in terms of c. Relativity alludes to the qualitative static distance (between two objects or "events") but explains the theory with respect to dynamic distance traveled.

In flat spacetime distance can be defined as coordinate separation in a consistent way. What is a ruler but a stick with coordinates marked off ? In SR each inertial observer has a set of coordinates and a definition of distance. The Lorentz transformation allows us to transform the coordinates between frames.

Case in point is the phenomenon of "length contraction".

Which is what happens when a distance in one frame is expressed in the coordinates of another frame.

It is completely consistent and your assertion

there's a fundamental error in the relativist's notion of distance

is incorrect.

 

[ghwellsjr]

Case in point is the phenomenon of "length contraction".
If I'm standing 20 yards away from a tree (where there's a measuring device) and a muon zips past me at near the speed of light, relativity theory says that the distance between the muon an the tree contracts.

SR says that in your rest frame, the muon itself is contracted but the distance the muon has to travel is not contracted. In the rest frame of the muon, the distance between you and the tree is contracted but not the muon itself. That's why it can survive long enough to make the trip.

Now did the static distance between me and the tree shrink or was it the distance between the muon and the tree? And if the answer is the later, then say there's a rock between me and the tree, did the distance between the rock and tree also shrink?

There are two answers depending on whether you are using your rest frame or the rest frame of the muon. In your rest frame the distance between the rock and the tree does not shrink. In the rest frame of the muon, the distance between the rock and the tree is shrunk.

You can use either rest frame (or any other frame) to analyze the situation and they will all get the same answer, which is even though the half-life of the muon is too small for it to survive traveling "long" distances", from your rest frame, it survives because it's clocks are running slow and from its rest frame, it survives because it doesn't have very far to travel.

 

[ghwellsjr]

I hope you realize that the issue we are talking about isn't confined to distances between objects in empty space, the same issue exists between the shape of a single physical solid object on the surface of good old earth. The Michelson-Morley experiment is what started this whole thing. It was a single very large, very solid, very massive object that seemed to be changing its dimensions simply by being rotated. How do you understand Lorentz contraction when applied to MMX?

I understand it as an indirect inference from a null-experiment.

Yes, that is very true. I'm glad you agree with me and everyone else on this point.

 

[alkadh455]

Wow, what a question. Well, we all know that time is the duration it takes actions to happen. Time is the fourth dimension, as Einstein viewed it. People before Einstein, like Newton, viewed time as a definite quantity. They viewed it as a definite measurement that is the same for everybody. Then came Einstein, and said that time is in fact relative, it is not an equivalent quantity for everyone. First, he said that the ultimate speed of the universe is the speed of light (you can't go faster than the speed of light). He also said that time is a relative measurement, it depends on your speed; the closer you travel to the speed of light, the slower time beats. Also, time beats faster if you are away from gravitational pull (that's why our GPS works the way it does. It has to take General Theory of Relativity into consideration).That is our basic understanding of time.Time travel to the future is very possible, you just have to go on fast speeds and you age less than your twin, you are in some sense a traveler to the future, However, we don't really know for time travel to the past, because you can't change your past. There are also some new theories on time such as wormholes, and string theory's tiny curled up extra dimensions... The subject of time is really a huge subject, and physicists are still investigating on time.

 

[cshum00]

As far as I'm concerned, time is not a dimension. it's simply a number line. it's then endowed with orthogonality and combined with the 3 "spatial" dimensions. as such mathematicians have simply just created, lie u said, a useful framework for modeling the physics of objects in space.

You are getting it all wrong. Time IS a dimension. The problem is that you are mixing between "spacial dimension" and dimension in general!

In math, dimension can be ANYTHING! as long as you can represent it on a number line and have it to be useful for mathematical representations and calculations.

In science, dimension takes a further step and says that it is anything that is a FUNDAMENTAL QUANTITY that that is why we assign a symbol for it's dimension.
http://en.wikipedia.org/wiki/Physical_quantity#Base_quantities.2C_derived_quantities_and_dimensions"

TIME is a FUNDAMENTAL QUANTITY! You don't have to trust the wiki link that i sent you but search and look around books and you will find that TIME IS INDEED A DIMENSION!

Stop being stubborn and saying that when a scientist say dimension they must mean spacial dimension; which IS NOT! Spacial dimension is a subset of dimension!

As for the word space part, mathematicians do use the word space when they could actually mean just dimension. Meaning when mathematicians say space, they don't mean spatial dimension but dimension in general and it occurs! And for scientists who have deep math background do so as well! That is why some people misunderstand that when some scientist say space referring to spatial dimension of space which might not be the case depending on the content of the speech!

 

[Passionflower]

TIME IS INDEED A DIMENSION!

In Galilean spacetime time is surely a dimension, but is that the case in relativity?

I think in relativity time is the length of a path between two events in four dimensions. You think I am wrong?

 

[cshum00]

In Galilean spacetime time is surely a dimension, but is that the case in relativity?

I think in relativity time is the length of a path between two events in four dimensions. You think I am wrong?

I think you are right. In the contents of your speech, you are clearly referring that the "length of a path" of the "four dimensions" that you are working on. Your thinking actually resembles to a filmstrip where each strip of the film is a point of the time path and inside each strip instead of a 2-D space dimension picture, you have a 3-D dimension picture.

Edit:I think that "path" is good enough. "Length of a path" would be more like the total amount of time specific time-frame.

 

[Passionflower]

I think you are right. In the contents of your speech, you are clearly referring that the "length of a path" of the "four dimensions" that you are working on. Your thinking actually resembles to a filmstrip where each strip of the film is a point of the time path and inside each strip instead of a 2-D space dimension picture, you have a 3-D dimension picture.

Edit:I think that "path" is good enough. "Length of a path" would be more like the total amount of time specific time-frame.

So it appears that you agree.
If that is so then time cannot be something else as well right? Thus do you agree that time is not a dimension?

 

[cshum00]

So it appears that you agree.
If that is so then time cannot be something else as well right? Thus do you agree that time is not a dimension?

I am confused. How does agreeing that time is one of the 4 dimensions you mentioned leads to that time is not a dimension?

 

[Passionflower]

I am confused. How does agreeing that time is one of the 4 dimensions you mentioned leads to that time is not a dimension?

Where did I write that "time is one of the 4 dimensions"?

 

[cshum00]

Where did I write that "time is one of the 4 dimensions"?

Ok, then what are those 4 dimensions then? If time is not one of those 4-dimensions then i would disagree. I guess that i did not get the right picture for your statement.

 

[Passionflower]

Ok, then what are those 4 dimensions then? If time is not one of those 4-dimensions then i would disagree. I guess that i did not get the right picture for your statement.

Ok, so let's assume that one of the 4 dimensions is time then what is the length of a path between two events in those 4 dimensions?

 

[cshum00]

Ok, so let's assume that one of the 4 dimensions is time then what is the length of a path between two events in those 4 dimensions?

Ok, it would be like i mentioned before on my edit:

Edit:I think that "path" is good enough. "Length of a path" would be more like the total amount of time specific time-frame.

In other words, it would be the total amount of time that it takes from one event to the second event.

 

[Passionflower]

Ok, it would be like i mentioned before on my edit:


In other words, it would be the total amount of time that it takes from one event to the second event.

Yes and that is not time?

 

[DrGreg]

Passionflower, are you aware of the difference between coordinate time, which is one of the 4 dimensions of spacetime (for a given choice of coordinates), and proper time which is the "length" of a 4-dimensional curve or line (and is independent of any choice of coordinates)?

 

[cshum00]

@Passionflower
Ok, i think i got the root of our problem and the solution.

Let's start with your original statement:
"I think in relativity time is the length of a path between two events in four dimensions."

-First, i will modify your statement to: "Time is a path between two events in four dimensions."
-I remove the word relativity because i am not sure in which relativity you are referring to; the general or special. Also, specifying special relativity will make one of the four dimensions to time which in our case we don't want to.
-It is not length because they are two different things. For example, length would be like: it took five minutes for me to write my essay. While for time i would be saying, according to Easter Time clock, i finished my essay at 10:42AM.
...
-This will require us to look at dimension not as the scientific meaning of dimension but the mathematical one. When i say this, i mean anything CAN be a dimension.
-Saying that, we will look at event as a dimension. For example, e₁ (event1), e₂ (event2) and so on.
-So, according to the modified statement we are looking at time as t(e, x, y, z) where e=event, x=spacial-dimension1, y=spacial-dimension1, z=spacial-dimension3.
-In other words, time is a function of event, and 3 spatial dimensions. And length of the path of 2 points of time would be how much time lapsed between two events.
-This support the filmstrip idea where each event would be each snapshot on the film, and the difference in length between two film strips is the total time it took for those two events to happen.

Now, the next problem is when i said that time is one of the four dimensions.
-In the case of viewing time as part of the dimension, i would actually be defining event as a function of time and the 3 spatial dimensions or e(t, x, y, z).
-So, if we see time as a function of event, we would intuitively make event as a dimension.
-And if we make time as a dimension, we intuitively create an event function instead.
-Next, is what is the length of the path between two events? It is NOT the total amount of time between two events. I was wrong. Yes, sorry and i apologize. I don't know what it means unless we give a meaningful value to each point of event.

 

[Passionflower]

Passionflower, are you aware of the difference between coordinate time, which is one of the 4 dimensions of spacetime (for a given choice of coordinates), and proper time which is the "length" of a 4-dimensional curve or line (and is independent of any choice of coordinates)?

Coordinate time is a dimension on a chart of spacetime. But mapping an observer's proper time onto the coordinate time axis of a chart is not the same as claiming that one single spacetime dimension represents time. It does not, time is represented by a path between two events inside this spacetime. For a Galilean spacetime you would be correct but not for a Minkowski spacetime.

While proper time always describes what a physical clock measures, coordinate time may or may not do that. Clearly coordinate time cannot be a dimension of time because if we have a simple spacetime with two observers taking a different path with a different length between two events then clearly coordinate time cannot represent time for both observers, time for each observer is the path length between the events not the coordinate time. Yes we can use different coordinates for each observer but then we are not talking about dimensions of spacetime but observer dependent charts where the proper time is modeled by using the time dimension of the coordinate chart for that particular observer.

Don't mix up a coordinate chart of spacetime with spacetime itself.

 

[cshum00]

I am but what is the point?

While proper time always describes what a physical clock measures, coordinate time may or may not do that. Clearly coordinate time cannot be a dimension of time because if we have a simple spacetime with two observers taking a different path with a different length between two events then clearly coordinate time cannot represent time for both observers, time for each observer is the path length between the events not the coordinate time. Yes we can use different coordinates for each observer but then we are not talking about dimensions of spacetime but simply observer dependent maps where the proper time is modeled by using the time axis of the coordinate chart for that particular observer. But then we mix up the chart with spacetime itself.

I am confused. Unless you mean something else by coordinate, isn't time as a coordinate the same as time being a dimension?

About the problem of two observers not being represented in a single graph is because each observer's coordinate system is shifted with respect to each other. For example, if my origin is not your origin but shifted on a certain way, then when i say this point of space, it won't be the same point of space in your coordinate system. That is why we need to do transformations.

Edit: BTW, did my previous post clear our misunderstandings.

Just because we are defining time as a function of other coordinates, it doesn't mean that time is not a dimension. For example, i would define a function to be z(x,y); but it doesn't mean that z is not a dimension. And most importantly, time is a fundamental quantity which adds the requirement of being a dimension for science.

 

[Passionflower]

I am confused. Unless you mean something else by coordinate, isn't time as a coordinate the same as time being a dimension?

Think about the different between a coordinate system of spacetime and spacetime itself. Two different things.

About the problem of two observers not being represented in a single graph is because each observer's coordinate system is shifted with respect to each other. For example, if my origin is not your origin but shifted on a certain way, then when i say this point of space, it won't be the same point of space in your coordinate system. That is why we need to do transformations.

So clearly you must realize you are dealing with charts of spacetime not spacetime itself.

Time is a path in spacetime not a dimension of spacetime. If time would be a dimension of spacetime all observers would agree on such time as is the case in Galilean spacetime.

 

[cshum00]

Think about the different between a coordinate system of spacetime and spacetime itself. Two different things.

Then to clear things up, i have been using them as the same thing. I don't get what you mean by coordinate. Can you explain further?

So clearly you must realize you are dealing with charts of spacetime not spacetime itself.

Time is a path in spacetime not a dimension of spacetime. If time would be a dimension of spacetime all observers would agree on such time as is the case in Galilean spacetime.

I am confused here. How can you see time dilation if you are on the Galilean spacetime? The reason why Galilean relativity could not do gave discrepancy errors was is because it did not have transformation of coordinates (which is what Special Relativity did). I think your problem lies that you don't understand that each observer is in their own coordinate system which needs to be transformed to that they could agree on what they are observing.

 

[Passionflower]

I think your problem lies that you don't understand that each observer is in their own coordinate system

I don't understand that each observer is in their own coordinate system?

So let me try to follow you, each observer is in their own coordinate system and all these unique coordinate systems relate how to spacetime and in particular the specific dimension you claim is time?

 

[cshum00]

So let me try to follow you, each observer is in their own coordinate system and all these unique coordinate systems relate how to spacetime and in particular the specific dimension you claim is time?

Not only time, but also for the 3-spacial dimensions too. There is also length contraction. I don't want to be rude but i am guessing that you didn't actually go through the mathematics of it but only read the conclusions instead. .Although the conclusions might be counter-intuitive, if you actually follow through the mathematics and the reason for such transformations; you should be able to have a better understanding of it

 

[Passionflower]

I don't want to be rude but i am guessing that you didn't actually go through the mathematics of it but only read the conclusions instead. .Although the conclusions might be counter-intuitive, if you actually follow through the mathematics and the reason for such transformations; you should be able to have a better understanding of it

As I said before I think that time is a path in spacetime not a dimension of spacetime. Feel free to introduce mathematics to show how wrong I am.

 

[cshum00]

As I said before I think that time is a path in spacetime not a dimension of spacetime. Feel free to introduce mathematics to show how wrong I am.

The word space-time refes to 3-spacial dimensions and one time dimension!

Let's modify your statement so that you see what are you saying mathematically.

x is a path in x-y dimension not a dimension of x-y.
Or mathematically, x = x(x, y)!

I think you missed my last post on page 5. You got mixed with my other earlier comments. Read my last post on page 5 which clarifies our earlier arguments then come back and explain to me what you mean by coordinates and how come time is not a dimension since I am unable to picture your problem.

 

[Passionflower]

The word space-time refes to 3-spacial dimensions and one time dimension!

Do you seriously think that such an argument would convince me?

Let's modify your statement so that you see what are you saying mathematically.

x is a path in x-y dimension not a dimension of x-y.
Or mathematically, x = x(x, y)!t

Surely you must be joking!

 

[cshum00]

Do you seriously think that such an argument would convince me?

No, i am not trying to convince you. It is the truth. Research the word spacetime. It is just like i said. It means 3-spacial dimensions and one time dimension.
http://en.wikipedia.org/wiki/Spacetime

Surely you must be joking!

No, i am not joking. Ask a mathematician to translate that statement to math for you and see what you get. I might be wrong but your statement is just as outrageous as it is.

 

[DaveC426913]

Passionflower, conventional spacetime is defined as the 3 physical spatial dimensions and one timelike dimension.

It is not really open to interpretation or opinion.


There are theories that posit other numbers, and you are welcome to refer to them, or alternately, develop a paper for your own ideas and submit it to the appropriate forum.

But again, not really an opinion thing.


Perhaps when you are describing a path, you are referring to the fact that timelike dimensions are distinct from space-like dimensions in that timelike dimensions allow movement in only one direction - forward - and at a constant speed. We must travel through the time dimension.

 

[Passionflower]

It is not really open to interpretation or opinion.

Well so if we have one single time dimension then what is a path in spacetime according to you?

 

[DaveC426913]

Well so if we have one single time dimension then what is a path in spacetime according to you?

A path could go from [xyzt] to [x'y'z't'].

Because we have freedom in spatial dimensions, we could instead have chosen to go from [x'y'z't] to [xyxt'], but we cannot go from [x'y'z't'] to [xyzt].

 

[Passionflower]

A path could go from [xyzt] to [x'y'z't'].

Because we have freedom in spatial dimensions, we could instead have chosen to go from [x'y'z't] to [xyxt'], but we cannot go from [x'y'z't'] to [xyzt].

?

Are you going to explain what you think a path in spacetime repesents?

 

[DaveC426913]

No, I'm simply trying to stop you from violating PF guidelines in your attempt to freely interpret what you think spacetime and spacelike and timelike dimensions are.

You asked me what a path through 4D spacetime might be. I obliged. It will be defined by the connection between two points each defined by 4 coordinates.

 

[Passionflower]

violating PF guidelines

What guidelines am I violating?

So I take it you are not going to explain to me what you think a path in spacetime represents?

 

[DaveC426913]

What guidelines am I violating?

Not 'are', but are heading that way, or so it seems. You seem to be creating you own definitions for dimenion and spacetime.

The PF rules put a leash on overly-speculative posts. PF is about mainstream physics.

I'm not trying to be a heavy, I'm just cutting to the chase of the argument you've been having for about 20 posts. Spacetime is a well-known concept.

So I take it you are not going to explain to me what you think a path in spacetime represents?

You ask the oddest questions. Path is your word. Represent is your word. Why am I obliged to answer a question for which you frame the vocabulary?

 

[Passionflower]

You ask the oddest questions. Path is your word. Represent is your word. Why am I obliged to answer a question for which you frame the vocabulary?

Really that is odd?
You accuse me of creating my own definitions or being overly speculative and you are not familiar with paths in spacetime?

Despite you recognition as a 'Science Advisor' on this forum I am seriously questioning your expertise in this matter.

You accuse me of being overly speculative, what do I speculate about?

 

[DaveC426913]

You accuse me of creating my own definitions or being overly speculative and you are not familiar with paths in spacetime?

Who said I am not familiar?

You've gone from shouting down cshum00 to shouting at me. You are very confrontational in your discussion style.


I don't really have any contribution to the discussion, except my original point of order, which is that spacetime is a conventional concept.

 

[Passionflower]

You've gone from shouting down cshum00 to shouting at me. You are very confrontational in your discussion style.

I am not confrontational, the only person who is confrontational is you as you accuse me of something without any base.