Does Time Expand in All Directions in the Universe?

  • Thread starter Thread starter Whitefire
  • Start date Start date
  • Tags Tags
    Direction Time
Click For Summary
The discussion explores the concept of time expanding in all directions within the universe, suggesting that time may not flow uniformly across different locations. The idea posits that as galaxies move apart, their relative time perception could differ, leading to the notion that time could appear to pass slower for distant galaxies. This perspective aligns with the expansion of the universe and the effects of dark energy, proposing that time behaves differently depending on spatial positioning. The conversation emphasizes the need for clear definitions and predictions to validate or invalidate this hypothesis against established cosmological principles. Ultimately, the discussion invites further exploration of time's nature and its implications for understanding the universe.
  • #31
petm1 I have already shown why your claim in the second paragraph is false when we have a way of slicing up spacetime into constant time slices which we can do for the FLRW universe.
 
Space news on Phys.org
  • #32
petm1 I have already shown why your claim in the second paragraph is false when we have a way of slicing up spacetime into constant time slices which we can do for the FLRW universe.

Sorry I must admit that using the scale factor of the universe as a function of time looks like the best calendar man has to date but I fail to see why this proves my view false.
 
  • #33
I think the OP might be confusing the dimension of time as it pertains to math with imagery in their head of what things look like as time passes. Kind of like an animated movie where all the cells are overlapped so everything looks like a blob.

Whitefire: If you're sitting in a spaceship floating with a view point of the Earth above it's orbital plain and take a picture of the Earth every day for a year, then mash them all together, you'd get a picture of a blue ring around the sun. But all you've done is take a picture of matter moving over the course of a year, the direction the Earth is traveling isn't the "direction of time", just like the universe isn't expanding in the direction of time.
 
  • #34
Spourk, in your image you are are cutting out the time direction entirely. You are also cutting out third space dimension, and leave only 2D image. This is not what I mean.

directions_dimensions.jpg


In pictures 1,2,3 the left and right always seem to point in 'one direction' for the line.
In pictures 4, 5 and 6 up and down always seems to point in 'one direction' for the paper.
in pictures 7, 8, 9 future and past would also always seem to point in 'one direction' for the space.

But any third observer would be wiser.
 
  • #35
this article here may help you out a bit its on De-Sitter and anti-De-sitter. De-Sitter is a matter removed modelling system , anti De_Sitter is negative curvature.

http://www.bourbaphy.fr/moschella.pdf

the reason I feel the article may help is that it has a decent light cone coverage without unnecessary complexity. May help (keep in mind any gravitational effects is due to energy mass as opposed to matter mass)
 
  • #36
Whitefire said:
Spourk, in your image you are are cutting out the time direction entirely. You are also cutting out third space dimension, and leave only 2D image. This is not what I mean.

directions_dimensions.jpg


In pictures 1,2,3 the left and right always seem to point in 'one direction' for the line.
In pictures 4, 5 and 6 up and down always seems to point in 'one direction' for the paper.
in pictures 7, 8, 9 future and past would also always seem to point in 'one direction' for the space.

But any third observer would be wiser.

Hovering above a star to observe planet's orbital path is hardly a 2D image... and my point in the first place is that time doesn't move in a direction. What I tried to do was explain what I think is confusing you about the direction of time, which included all 3 spatial dimensions moving through a 4th time dimension, (which itself isn't moving in a direction).
 
  • #37
Time dilates in every direction. I may be able to talk about the expansion rate of space between two or more objects with two or more directions between them but I would also be correct to speak of space as a single entity dilating in time. Space and time are two ways we use to describe the same thing with the motion within space being visible and the motion of time not so. Think of our visible universe as a affine space that is always dilating and every single thing has the same motion, outward. I do not see matter dilating but I do exist as a single part of a accelerated frame we call Earth also I do not see the motion of a photon I see it as a color yet to explain each I do need time. A clock may count its own simultaneous existence as a clock but the ticks measure the difference between simultaneous moments we see via photons. For this reason I think of time as all directions for they all exist in time with the same motion, keep in mind that all motion I see is twisted within a focal point from the three dimensions of space's outward motion into the pseudo time of inward motion i think of as my present.
 
  • #38
What you have said is just word salad. If you can express your thoughts mathematically then please do so, otherwise you are just uttering nonsense.
 
  • #39
WannabeNewton, I believe that even without mathematic symbols one can express ideas logically and meaningfully.

Spourk, I feel depressed by the way you interpret my words. "you'd get a picture of a blue ring around the sun" is a 2D picture and you cannot represent time/change in 2D without representing velocity. That is why all my representations of time have arrows and why I am talking about directions. Yes they are not merely directions of our '3D' space as we understand it from every day life. But there is just no other word for it. If you really want to make sense of your example, you would 1) need to consider something much larger than Earth and Sun; 2) notice that as you were observing your 'Earth's' movement, it would seem to move slower in the distant fragments of its orbit (relative to you), and faster when near you. You can delete the sun from the picture. In relation to sun, this effect has no meaning, because the sun is always generally the same distance from Earth. Plus 3) I am not sure if this would really happen, even if these were galaxies, not planet and star, because gravity seems to mess with the whole idea.

@Mordred: I thank you but I grasp the concept of light cones quite well. Believe or not but I have imagined light's progress in time as a (very flattened) "X" long before I saw the name 'light cone'. It is a very useful tool, but you are probably aware of the fact that light cones are also relative, meaning that in reality a light cone for point A is different than the light cone for point B. And what I am talking about here is simply (?) relativity, so light cones are only so much useful. You cannot take a single picture, a 'lightlike' image of the universe, and try to deduce how time works from that.

For relativity, you really, really need the third observer. Forget about how you percieve time. Forget about how time passes for other objects relative to you. You need to observe how objects relate to each other.

Perhaps the discussion is not as meaningful as I thought. I have a very specific understanding of spacetime and perhaps you are just used to picture it differently. I see time dilations as movements in specific direcitions, and it's that simple.

This kind of thinking can generate, however, some interesting thoughts. For example, I quite taken by an idea that as space expands, time contracts, and we are not going to have an infinite amount of it. If there was a Big Bang, then there perhaps will be a Big End ---perhaps a Big Freeze, but I would not really bet it is the same. In the Big End we would have the galaxies actually being torn apart by the same process which we now refer to as 'accelerated expansion of the universe', then matter itself being destroyed, and time coming to a stop... or a 'middle', if I am correct...

Good night :)
 
  • #40
Whitefire said:
I recently had this idea (which perhaps is not a new one, but I have never heard of it), that on the scale of the entire universe, time expands in all directions at once.
That statement has no meaning since direction is a concept that pertains only to spatial relationships and not to temporal ones.

Whitefire said:
If we look around us, we generally understand time as 'direction of changes' ….
Who are “we”? Certainly not physicists who do not assign any kind of notion to time as having a “direction.”

And the only sense that one can give to time being orthogonal to space is a mathematical one, not a physical one. Take the spacetime physics that one works with in special relativity as an example. In spacetime physics one uses 4-vectors which reside in spacetime. The mathematical meaning to orthogonal uses the inner product between 4-vectors. When the inner product is zero then the vectors are said to be orthogonal. But the meaning of orthogonal in this context is different than in Euclidean geometry. For example; in spacetime physics the 4-momentum of a photon is orthogonal to itself because the inner product of the 4-momentum of a photon with itself is zero.

Chalnoth said:
The dimension of time is orthogonal to the dimensions of space.
That is incorrect. In the first place it’s mathematically incorrect to speak of a dimension as being orthogonal to something. It’s only meaningful for a 4-vector, or a spatial/temporal axis to be orthogonal to each other. And only then does it have a mathematical meaning, not a physical one.

Chalnoth said:
Yes, time has a direction, but that direction is not up or down, left or right, forward or backward.
That is incorrect. Time does not have a direction. Direction is only something that pertains to spatial relations, not temporal ones. Only when one draws these things on a piece of paper do they actually have physical direction.

Direction quite literally only pertains to spatial directions, not temporal ones. However one does speak of them as having such thing but that’s merely for purpose of visualizing objects in spacetime is that done. There is no physical meaning to it.
 
  • #41
Popper said:
That is incorrect. Time does not have a direction.
This is a very broad statement that is incorrect in and of itself. See here:
WannabeNewton said:
Note that for a space-time with a space-llike foliation by a one-parameter family ##\Sigma_{t}## and an open subset of it covered by a coordinate chart adapted to the foliation (e.g. Schwarzschild coordinates for the associated space-time) we can interpret the coordinate vector field ##(\frac{\partial }{\partial t})^{a}## as the "time direction" or "flow of time" (you can interpret ##\nabla^{a}t## in the same way since the vector fields will be proportional). This is of course a very specialized situation since general space-times don't admit such coordinate charts / foliations.
 
  • #42
I don't get why people treat integral curves of ##\nabla^{a}t## so differently from integral curves of space-like vector fields, apart from the trivial differences. When space-like foliations exist, the hypersurface orthogonal vector field ##\nabla^{a}t## can geometrically be interpreted as the "flow of time". Anyone who has seen the Hamiltonian formalism of general relativity will not find anything alien in this as they will have seen even more general vector fields ##t^{a}## representing the "flow of time" chosen along with a time function ##t## such that the surfaces ##\Sigma_{t}## are space-like Cauchy surfaces and such that ##t^{a}\nabla_{a}t = 1##.
 
  • #43
Direction quite literally only pertains to spatial directions, not temporal ones.

I don't think we can resolve this without a really good definition of 'direction'. A one that we all would agree upon.
 
  • #44
Whitefire said:
I don't think we can resolve this without a really good definition of 'direction'. A one that we all would agree upon.
There is a really good one that's agreed upon by everyone who understands it: A unit vector in the tangent space at the event where you want to assign time a direction.

Edit: A unit vector defines a direction in spacetime. But it can't by itself give us a reason to think of that direction as the direction of time.

The only thing that can define a direction of time is the kind of stuff that WannabeNewton is talking about. First you slice up spacetime into 3-dimensional hypersurfaces labeled by a real parameter t, so that each event belongs to exactly one of these hypersurfaces. Now if we want to find the direction of time at an event p, we would look at the hypersurface that p belongs to. There are two directions that are orthogonal to this hypersurface at p. In one of these directions, t is increasing, and in the other direction, t is decreasing. The direction that's orthogonal to the hypersurface and such that t is increasing, can then be considered the direction of time at p.

Note that this direction depends on our choice of how to do the "slicing".
 
Last edited:
  • #45
Indeed so for the FLRW metric ##ds^2 = -d\tau^{2} + a^{2}(\tau)dS^{2}## just take ##n^{a} = (\frac{\partial }{\partial \tau})^{a}## which, in the coordinate basis, is just ##n^{\mu} = \delta^{\mu}_\tau## or put more suggestively ##\mathbf{n} = (1,0,0,0)##. You can consider this as the time direction given the spatial slices ##\Sigma_{\tau}##, which are of course orthogonal to ##n^{a}##. Recall that ##\tau## is the proper time as measured by a clock carried along a chosen congruence of isotropic observers in the FLRW universe so the time direction is just pointing along the unit normal to this congruence i.e. ##n^{a} = u^{a}## where ##u^{a}## is the 4-velocity field of the congruence.
 
  • #46
First you slice up spacetime into 3-dimensional hypersurfaces labeled by a real parameter t, so that each event belongs to exactly one of these hypersurfaces.

And why do you need to do the slicing? Why can't we consider a single point?
 
  • #47
Whitefire said:
And why do you need to do the slicing? Why can't we consider a single point?
Because a point doesn't determine a direction. You need something like a point and a timelike curve through that point, or a point and a spacelike hypersurface through that point.
 
  • #48
Whitefire said:
And why do you need to do the slicing? Why can't we consider a single point?
Another way to look at it, in addition to Fredrik's point, is that time exists at every location, so while we're at it, why not define what we mean by time everywhere? Then we have a space-like surface which we can define as "now" everywhere, and the time direction points perpendicular to that surface (no, you can't visualize it, because it requires four-dimensional thinking to visualize, and we can only think in three dimensions).

Incidentally, one of the better discussions of extra dimensions is this one by Carl Sagan from Cosmos:
 
Last edited by a moderator:
  • #49
Whitefire said:
I don't think we can resolve this without a really good definition of 'direction'. A one that we all would agree upon.

Is "forward" sufficient? It does not rule out any precise direction except backward and sideways.
 
  • #50
write4u said:
Is "forward" sufficient? It does not rule out any precise direction except backward and sideways.
"Forward" is the direction we're talking about how to define. Edit: I meant forward in time, not forward in space.
 
Last edited:
  • #51
Fredrik said:
"Forward" is the direction we're talking about how to define.

Is the future a "direction"?

IMO, it is a valid question.
 
Last edited:
  • #52
write4u said:
Is the future a "direction"?
In relativity, there are lots of directions that are labeled "timelike" (by a precise mathematical definition). Together they identify a region of spacetime that's sometimes called "the chronological future". The union of that set and its boundary is then called "the causal future". If what we mean by "the future" is one of these sets, then no, the future is not a direction. It's a set that identifies lots of different directions, not just one.

This is why we need something other than just an event in spacetime to single out which one of them to call the direction of time.
 
  • #53
Fredrik said:
"Forward" is the direction we're talking about how to define. Edit: I meant forward in time, not forward in space.

Thank you for clarifying your definition. I agree.
 
Last edited:
  • #54
Yup. Forward in time is a direction. It's just not a direction you can point.
 
  • #55
Chalnoth said:
Yup. Forward in time is a direction. It's just not a direction you can point.

That was my initial response, there is only forward "in time".
But then the OP question becomes meaningless!

Can time be approached from a physical viewpoint at all. IMO to speak of direction is misleading. Along with different spacetime coordinates, time exist in latent form everywhere in the universe. I always thought of it as a non-causal universal potential.

In wiki, I saw the section of sets, but that is merely an exercise in probabilities. So the direction of time is a probability? A set of indicators which suggest the direction of time in the future?
This can be demonstrated by the double slit experiment, which shows a probability function of possible events, but what does that have to do with time itself or more to the point, direction?

OK, allow me to clarify this in my mind. If tomorrow is an (as yet) unspecified direction how can we make calculations for anything other than a generalized statement that time will be moving in an unspecified direction toward "somewhen", but always along with a series of chronological events, such as me traveling west on a train. The actual duration in time to complete my trip is affected by my physical speed, but not by my direction of travel.

It makes no sense to me. It is the worldline, the continuation of a series of events that creates a chronological time frame for that series of events. It stands to reason that there needs be change in the physical conditions (which require time) for time to become measurable by the duration of the event.

IMO, time ONLY comes into existence as result of a physical action which 'requires' and 'creates' time to be able to become instantiated in physical space at a specific coordinate, which undergoes change or is different than the starting coordinate. This bridging of physical events creates time in the process as a byproduct, a result.

Time does not exist by itself, it is a latency, a potential of spacetime, which becomes measurable only as a result of a change or action "in physical space". Whithout any physical change to measure, what is the need for time? Let alone direction.

The use of space by physical events creates a simultaneous "forward in time" chronology for those physical events, but only at the "time" of the event, no matter what direction the physical event itself follows. Time is a directionless latency, which allows reality to instantiate in chronological order, no more, no less..

Time is a result and cannot be measured at all without physical change. We can "assign" an estimate of the "time it will take" for an event to complete itself, but that is probabilistic and completely depends on the actuation of the event. But as soon as the event begins, time will record the actual time used going always forward in time along with the unfolding of the event.

How about a definition which states that time is a non-causal latency which becomes measurable only as a result of change and the duration of that event in spacetime. Therefore time can be measured (or even projected into the future) along with the direction of the event, but not independently by itself as a direction of time.

Fredrik,
The only thing that can define a direction of time is the kind of stuff that WannabeNewton is talking about. First you slice up spacetime into 3-dimensional hypersurfaces labeled by a real parameter t, so that each event belongs to exactly one of these hypersurfaces. Now if we want to find the direction of time at an event p, we would look at the hypersurface that p belongs to. There are two directions that are orthogonal to this hypersurface at p. In one of these directions, t is increasing, and in the other direction, t is decreasing. The direction that's orthogonal to the hypersurface and such that t is increasing, can then be considered the direction of time at p.

Note that this direction depends on our choice of how to do the "slicing".

This brings the question; can time be associated with a single point "p" at all? Then the conclusion the time in one direction "increases" and "decreases" in the other direction, sounds odd. If time does indeed increases or decreases in certain directions it is because space increases or decreases in size in those directions. IOW, the directions are spatial, not temporal.

Time follows no temporal direction other than the direction of spatial events, which may be in any direction. As the spatial events progress, time progress along with that worldline. But the counting of time is always forward, as it cannot do anything else, it is a non-causal result of a previous action.

Please consider any of my "assumptions" as probing questions. As a fan of Bohmian mechanics I am really interested in this discussion. Moreover, I do not seek to dispute any accepted theories, but try to stay within established knowledge.
 
Last edited:
  • #56
write4u said:
In wiki, I saw the section of sets, but that is merely an exercise in probabilities. So the direction of time is a probability? A set of indicators which suggest the direction of time in the future?
This can be demonstrated by the double slit experiment, which shows a probability function of possible events, but what does that have to do with time itself or more to the point, direction?
I don't understand what you're talking about here, so I will just say that what we're talking about has nothing to do with quantum mechanics.

write4u said:
If tomorrow is an (as yet) unspecified direction how can we make calculations for anything...
Just pick a coordinate system and do the calculation in terms of the coordinates it assigns to events.

write4u said:
...other than a generalized statement that time will be moving in an unspecified direction toward "somewhen", but always along with a series of chronological events, such as me traveling west on a train. The actual duration in time to complete my trip is affected by my physical speed, but not by my direction of travel.
I don't understand anything you're saying here.

write4u said:
It is the worldline, the continuation of a series of events that creates a chronological time frame for that series of events. It stands to reason that there needs be change in the physical conditions (which require time) for time to become measurable by the duration of the event.
All time measurements (all clocks) involve some sort of change. That much is correct.

write4u said:
Along with different spacetime coordinates, time exist in latent form everywhere in the universe. I always thought of it as a non-causal universal potential.
...
IMO, time ONLY comes into existence as result of a physical action which 'requires' and 'creates' time to be able to become instantiated in physical space at a specific coordinate, which undergoes change or is different than the starting coordinate. This bridging of physical events creates time in the process as a byproduct, a result.

Time does not exist by itself, it is a latency, a potential of spacetime, which becomes measurable only as a result of a change or action "in physical space". Whithout any physical change to measure, what is the need for time? Let alone direction.

The use of space by physical events creates a simultaneous "forward in time" chronology for those physical events, but only at the "time" of the event, no matter what direction the physical event itself follows. Time is a directionless latency, which allows reality to instantiate in chronological order, no more, no less..

Time is a result and cannot be measured at all without physical change. We can "assign" an estimate of the "time it will take" for an event to complete itself, but that is probabilistic and completely depends on the actuation of the event. But as soon as the event begins, time will record the actual time used going always forward in time along with the unfolding of the event.

How about a definition which states that time is a non-causal latency which becomes measurable only as a result of change and the duration of that event in spacetime. Therefore time can be measured (or even projected into the future) along with the direction of the event, but not independently by itself as a direction of time.
This sort of stuff is much too speculative for this forum, so you need to stop including such things in your posts.

write4u said:
This brings the question; can time be associated with a single point "p" at all?
Yes, it can. But as I said in #47, you need something other than that point to identify a vector that we can think of as the direction of time.

write4u said:
Then the conclusion the time in one direction "increases" and "decreases" in the other direction, sounds odd. If time does indeed increases or decreases in certain directions it is because space increases or decreases in size in those directions. IOW, the directions are spatial, not temporal.
No, this is wrong. I'm talking about a line through point p that's orthogonal to the 3-dimensional spacelike hypersurface that we think of as "space". The parameter that labels the hypersurfaces will have some value t(p) at p. The point p divides the line into two pieces, one on which the parameter is greater than t(p) and one on which the parameter is less than t(p). The line has two tangent vectors of unit "length" at p. One of them points to the part of the line where the parameter has a greater value. It makes sense to think of that tangent vector as the direction of time.
 
  • #57
Fredrik,
write4u,
This brings the question; can time be associated with a single point "p" at all?

Yes, it can. But as I said in #47, you need something other than that point to identify a vector that we can think of as the direction of time.

But what is the "something other"? Another set of points (a geometrical construct)?

This will be my last post on this subject, as I am not thoroughly familiar with tangents and vectors in spacetime other than as mathematical spatial geometric constructs.

But what I understand from what you just described seems to establish worldlines for a spatial reference system consisting of more than one point in space (by any other name). A "chosen" theoretical geometric reference system. IOW, in the experiment the experimenter can create any direction depending on the choice of coordinates (points). What the experimenter cannot do is alter the forward chronology of time intervals as it measures the spatial construct.

It is in the action of choosing vectors or tangents or any other geographic configuration that we create the apparent direction of time because time is always created during the action or the change and therefore would follow the spatial direction of the identified events or points.

IMO, the slicing experiment creates the condition of the direction of a worldline. Nevertheless, whatever spatial direction is indicated, it is a result of this action. If we were to change our reference points, the direction of time would follow those coordinates in space and the result might contradict the original directional tendency, but regardless of spatial direction time accompanies every event in every direction but always forward in time. Time itself has no direction except 'forward in time". There is no going 'backward in time' other than observationally and that's relativity, no? But even the act of observing the 'past' creates a worldline forward in time for the observer.

I do promise to look further into potentials of tangents and vectors, as right now they just seem spatial measurements, albeit in a sophisticated theoretical (geodesic) model.

Thank you for your patience and indulgence of my "speculations". I'll just observe to see if a consensus can be reached by the "learned fellows" about a direction of time which is other than forward in time.

Dang, one last question;

If I measure a square where the sides are 1 mile each. At 60 mph, I can establish a time measurement of 1 minute per side regardless of the direction of travel. When I arrive back at my starting point I will have traveled 4 minutes, the measurement chronology adding 1 minute for each side, but always accumulative and forward in time. If I have traveled 3 sides of the square and stop to measure the amount of time from where I came and measure the time it will take to the finish, I will notice that for this specific action more time lies in the "past" than is left in the "future" to complete the measurement. We can say 'we are almost there", but in this case where is 'there"? It is our starting point and we have spatially traveled 4 miles in the direction of 4 points (E,W,N,S.) of the compass but temporally we have traveled forward by 4 minutes in time, even as we ended up at the same starting point 4 minutes later.

I maintain that time is always a result coming into existence as a by-product of a physical event or physical change, or physical action in space, creating a worldline in spacetime. Of course space (a dynamic medium) itself is creating time and we have universal spacetime, but it is non-directional except that the dimension of time allows only the forward movement of time towards the future, along with the creation of future events.

Thanks for your patience.
 
Last edited:
  • #58
write4u said:
I maintain that time is always a result coming into existence as a by-product of a physical event or physical change, or physical action in space, creating a worldline in spacetime. Of course space (a dynamic medium) itself is creating time and we have universal spacetime, but it is non-directional except that the dimension of time allows only the forward movement of time towards the future, along with the creation of future events.

You kind of just answered all of your own questions.
 
  • #59
Spourk said:
You kind of just answered all of your own questions.

Thank you for the observation, but my question remains if am I wrong or not wrong but naive in my intuitions? As a layman my understanding of the universe comes from narratives. I trust that the scientific equations and formulas accompanying those narratives, are the proofs of those narratives.

Thus the question, does my narrative address the fundamental principle of the "time" part of spacetime as it pertains to the question asked in the OP?
 
  • #60
write4u said:
But what is the "something other"? Another set of points (a geometrical construct)?
I answered that in #47, and yes, it's something geometrical.
write4u said:
But what I understand from what you just described seems to establish worldlines for a spatial reference system consisting of more than one point in space (by any other name). A "chosen" theoretical geometric reference system. IOW, in the experiment the experimenter can create any direction depending on the choice of coordinates (points). What the experimenter cannot do is alter the forward chronology of time intervals as it measures the spatial construct.
Sounds about right.
write4u said:
It is in the action of choosing vectors or tangents or any other geographic configuration that we create the apparent direction of time because time is always created during the action or the change and therefore would follow the spatial direction of the identified events or points.
Langauge like "time is created" isn't used anywhere in relativity, or in any other established theory of physics.
write4u said:
IMO, the slicing experiment creates the condition of the direction of a worldline. Nevertheless, whatever spatial direction is indicated, it is a result of this action. If we were to change our reference points, the direction of time would follow those coordinates in space and the result might contradict the original directional tendency, but regardless of spatial direction time accompanies every event in every direction but always forward in time. Time itself has no direction except 'forward in time". There is no going 'backward in time' other than observationally and that's relativity, no? But even the act of observing the 'past' creates a worldline forward in time for the observer.
I'm not sure I understand what you're saying, so it's hard to comment on whether this is right or wrong.
write4u said:
If I measure a square where the sides are 1 mile each. At 60 mph, I can establish a time measurement of 1 minute per side regardless of the direction of travel. When I arrive back at my starting point I will have traveled 4 minutes,
A clock at the corner where you start will tell you that 4 minutes have passed, but the number of minutes that you will have aged is
$$4\cdot\sqrt{1-\left(\frac{60\cdot\frac{1609.334}{3600}}{299792458}\right)^2}\approx 3.999999999999984.$$ This is if we ignore the that infinite acceleration is impossible in the real world.
write4u said:
the measurement chronology adding 1 minute for each side, but always accumulative and forward in time. If I have traveled 3 sides of the square and stop to measure the amount of time from where I came and measure the time it will take to the finish, I will notice that for this specific action more time lies in the "past" than is left in the "future" to complete the measurement. We can say 'we are almost there", but in this case where is 'there"? It is our starting point and we have spatially traveled 4 miles in the direction of 4 points (E,W,N,S.) of the compass but temporally we have traveled forward by 4 minutes in time, even as we ended up at the same starting point 4 minutes later.
In any inertial coordinate system, your spatial coordinates will be what they were at the start, but your time coordinate will be different. You are at the same location (in "space", as defined by the coordinate system), but at a different event (i.e. a different point in spacetime).
write4u said:
I maintain that time is always a result coming into existence as a by-product of a physical event or physical change, or physical action in space, creating a worldline in spacetime. Of course space (a dynamic medium) itself is creating time and we have universal spacetime, but it is non-directional except that the dimension of time allows only the forward movement of time towards the future, along with the creation of future events.
You're really giving me a hard time with comments like these. This is personal speculation and against the forum rules. There's no established theory of physics that says that time comes into existence as a byproduct of change, or that space creates time. The only reason I'm not giving you infraction points is that there are mathematical statements in SR that are somewhat similar to what you said.

1. An object moving in space traces out a curve in spacetime.

2. If there's a 1-parameter family of 3-dimensional spacelike hypersurfaces whose union is spacetime, then we can think of the parameter as time and the hypersurfaces as "space, at different times".
 
Last edited:

Similar threads

  • · Replies 11 ·
Replies
11
Views
3K
Replies
8
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
23
Views
3K
Replies
7
Views
4K
  • · Replies 17 ·
Replies
17
Views
2K
Replies
9
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K