Age Relative? Time, Speed and Paradox Explored

[Garth]

Unfortunately, I just don't see any evidence for a preferred foiliation of space-time.

Most of the serious attempts I see to justify this preferred foiiliation involve long-range scalar fields of one form or other.

This seems to be more or less a requirement .

Exactly - you are describing the theory of Self Creation Cosmology. (plenty of posts on that in these Forums) A Brans Dicke type scalar field endows particles with inertial mass and interacts with the matter field.

This winds up with the need for a new, previously undiscovered force to create the preferred frame. But there are some fairly strict limits on the existence of the direct formes of such fields, ones that interact directly with matter.

The Equivalence Principle is violated in SCC - but in Eotvos type tests only to about one part in 10^-17 about three orders of magnitude less than present experimental sensitivity. However the scalar field exerts a force on all particles, equally to within this variability (10^-17), but not on photons which "fall" ar a rate 3/2 the Newtonian acceleration of gravity, this is testable but it has not been done to date.

Theories in which the new undiscovered field interacts only indirectly with matter are trickier. These theories usually can be described by their PPN predictions about gravity. To date, relativity has always been correct - only time will tell as we continue to test it further whether or not its predictions continue to be correct.

In all previous tests SCC predicts the same outcomes as GR. However we await the results of Gravity Probe B - the first experiment able to distinguish between them.

Garth

 

[4newton]

Fredrik:
I am preparing a set of drawings and the total concept in one document; it will include your last request, which I interpret to be a drawing of the path of light between inertial frames in my drawing . I think having more detailed and labeled drawings will make it easier to understand. I will try to include answers to all your other comments at one time.

 

[Fredrik]

Excellent. I should probably tell you that I won't be able to visit this site tomorrow, so if you post it tomorrow you'll have to wait at least a day for a reply.

 

[4newton]

Fredrik and all:

Here is a drawing that will illustrate space-time from an absolute viewpoint. Because as shown before there is a disagreement of terms used. I will use terms that are defined by the drawing. No other meaning or connotation is intended.

The drawing is a Minkowski space-time illustration.

Line AG and line HI are the lines of spatial rest frames. Spatial rest frames have transitions only in the time dimension. All vertical lines in the drawing are spatial rest frames.

Line AF shows the slope of the speed of light.

The spatial distance separates AG and HI AH. A light pulse is sent from B in frame AG to point E in frame HI and reflected back to D. This is the normal path of light that is being reflected back to the starting point. It is seen that the path of light is of equal length in both directions.

With the requirement that the speed of light is constant AF, the path of light is drawn between frames JL and MO. Both frames JL and MO are moving with a constant velocity indicated by the slope of JL and MO, in this case equal to one-half the speed of light. The distance AH = JM.. The path of light is JKL. It is seen that the distance the light must travel is longer going from J to K then the path of light in the case of B to E.. However the distance from K to L is shorter than the light path from E to D.. The total time over the entire path is Q-D longer than B to D

The difference between BED and JKL is as stated in Special Relativity where ( v ) is the slope JL and ( c ) is the slope AF.

The two paths of light in the MM experiment are represented by paths JKL and BPQ with JKL being in the direction of travel and BPQ perpendicular to the direction of travel. Note the total time of travel is the same for both paths. Both one way times however changes with velocity.

I hope from this you can see that Minkowski space-time is absolute and that this is in total agreement with SR.

 

[Garth]

The drawing is a Minkowski space-time illustration.

I'm afraid not 4Newton! In your diagram you have drawn a Euclidean space not a Minkowski space. The sheet of paper that you used to draw the diagram is Euclidean and there is only so much that you can do with it to illustrate Lorentz transformations, well very little actually. You have to be very careful.

Basically a moving inertail frame of reference is not on a world-line that is simply a rotation of the observer's axes; otherwise Lorentz transformations would be cyclical, go fast enough (rotation by 2pi) and you would stand still!

Instead in a true Minkowski diagram a moving particle's world line asymtotically approaches the pi/4 AF dotted line.

I hope from this you can see that Minkowski space-time is absolute and that this is in total agreement with SR.

Nice try but no! - In a true Minkowski diagram moving inertial observers are equivalent, there are no preferred frames of reference.

Garth

 

[4newton]

Garth:
I would be very interested in seeing your

Minkowski diagram a moving particle's world line asymptotically approaches the pi/4 AF dotted line.

 

[Garth]

I do not have the means to send you a diagram.

However: Take your diagram, move J to A so the two systems have the same origin.

Now as J is moving relative to A his space and time axes have to be inclined at an angle to A's: J’s space axis is inclined upwards w.r.t. A’s.

On a Euclidean space diagram the space and the time axes are simply rotated, however on a Minkowski space diagram, on your diagram, J's space axis turns anti-clockwise and his time axis turns clockwise. From A's point of view J’s axes are no longer orthogonal but turned inwards.

However J's point of view is that it his own axes that are orthogonal, and it is A's axes that are 'turned inwards'.

As the axes of a 'moving' observer, as seen by a 'stationary' observer, turn inwards they asymptotically approach the light null world-line at pi/4 as the relative velocity approaches c.

The geometry of the light path reflected off your co-moving mirrors is the same in both frames of reference; they are equivalent.

I hope this helps, try drawing it again.
Garth

 

[4newton]

Garth:
As you rotate your axis of the moving frame what is your relationship to the speed of light line AF? Are you saying that you think the speed of light line also rotates?

 

[Fredrik]

You're still missing the point 4Newton. Most of what you said in #54 is correct, but it has very little to do with relativity. The only events in your diagram where relativity is relevant is K and N, where light is reflected off a moving mirror without losing speed (like a tennis ball would). There is absolutely nothing in your diagram that gives any indication about what events are simultaneous to a moving observer.

Look at the drawing I attached. (It's ugly because I did it in Paint). The line marked t' is the world line of an observer who is moving to the right. (The line marked t is the world line of an observer that you would describe as stationary). The thin lines that change direction when they reach the line marked x' are light rays that the moving observer emits to the right at times -t3, -t2 and -t1. Mirrors have been placed at locations in space chosen so that the reflected light will return to the moving observer at times t1, t2 and t3. The moving observer would of course disagree with the time coordinates and say that the rays were emitted at times -t3', -t2' and -t1' but what's important is that he would agree that the times from emission to event O (the origin) is the same as the times from event O to detection (at times t1', t2' and t3').

Think about what this means. If light is emitted at time -t1' and is reflected at some unknown time and returns at time t1, then the "unknown" time of reflection must be t'=0. The reflection event has the same time coordinate as event O, and is therefore simultaneous with it.

This means that the entire line marked x' is a set of events that are simultaneous to the moving observer. Actually, any line that is parallell to x' is a simultaneity line for the moving observer.

This is not so strange as it might seem. If you have already accepted that the speed of light is the same to everyone, you shouldn't be surprised to see that the slice of spacetime that the moving observer calls "space" (the x' axis) is the one that puts the world line of a light ray exactly half-way between the x' axis and the t' axis.

Do you still think horizontal lines are events that are simultaneous to any observer?

 

[4newton]

I have studied you drawing and I have great difficulty understanding the concept you are trying to show. Your speed of light line I assume is the 45-degree line. Which also corresponds to your other light lines and of course the lines that are perpendicular to your light lines are also speed of light lines in the opposite directions. I can also understand your line t’ if you intend it to be a world line of a moving frame. All this is the same as my drawings. I do not understand what you line x’ is intended to be. If it is a world line it is to the right of the speed of light line and therefore anything moving on that line would be moving faster than the speed of light. I am certain this is not what you intend to say. It would help if you could relate how you drawing has anything to do with observation or reality.

In my drawing lines JL and MO are the same as AG and HI only they are rotated according to relativity. A light source moving on line JL sends out a pulse along the speed of light path JK and is reflected by a mirror at K and back to the light source that would than be at L. This is the same as the light path BED.

If you use this method to make a clock and the distance between the source and the mirror and back to the source in BDE is equal to the distance that light travels in one second 300 km. Then the light in the BED would take 1 second to return to the source.

Like wise you will notice that the distance between J and M is also equal to 300 km but this frame is moving in space, in this case one-half the speed of light. The total path of the light JKL is longer then the path BDE even though the distance between the source and the mirror is the same in both cases. The light arrives back at the source in JKL at a later time compared to BDE. The time difference varies asymptotically as the speed of the moving frame approaches the speed of light line.

This is relativity.

The line MNO is to show that the same is true no matter which direction the light travels.

I think it would help if you and Garth would go back and read Einstein’s paper.

It is essential to have time defined by means of stationary clocks in the stationary system, and the time now defined being appropriate to the stationary system we call it “the time of the stationary system.”

Translated by W. Perrett and G. B. Jeffery.

I covered simultaneity in previous post please review them and let me know what you don’t understand.

---

 

[Fredrik]

I have studied you drawing and I have great difficulty understanding the concept you are trying to show.

OK. I'll try to explain it.

Your speed of light line I assume is the 45-degree line. Which also corresponds to your other light lines and of course the lines that are perpendicular to your light lines are also speed of light lines in the opposite directions.

That's exactly right.

I can also understand your line t’ if you intend it to be a world line of a moving frame. All this is the same as my drawings.

Also correct. I would say that t' is the world line of an observer moving at constant velocity. (I'm not saying it's wrong to call it the world line of a moving frame, only that I prefer to call it what I called it).

I do not understand what you line x’ is intended to be. If it is a world line it is to the right of the speed of light line and therefore anything moving on that line would be moving faster than the speed of light. I am certain this is not what you intend to say. It would help if you could relate how you drawing has anything to do with observation or reality.

This is the most important part of what I'm trying to say, so you shouldn't give up until you understand it. The line marked x' is obviously not the world line of an observer. As I said in my previous post, that line is a set of events that are simultaneous to the observer whose world line is the line marked t'. (All events on the line marked x' are simultaneous with the event O).

I also explained why we can be sure that those events are simultaneous in the moving observer's frame. If there is any particular part of that explanation that you think is difficult to understand, you should ask about that specific detail.

It's really hard to tell what you understand and what you don't understand. You seem to understand that the points in a spacetime diagram represent events, i.e. a location in space and time. To find the x coordinate of an event, just draw a vertical line through the event and see where that line intersects the x axis. To find the t coordinate of an event, just draw a horizontal line through the event and see where that line intersects the t axis. However, you don't seem to understand (or even care) how to find the coordinates that another observer would use. This is not something that can be ignored.

Any event that has coordinates (t,x) in a spactime diagram will have have different coordinates (t',x') in the frame of an observer who's moving relative to the "spatial origin" (the point in space that's represented by the t axis in the diagram). It is easy to find the set of events that have x'=0. This is just the world line of the observer. This is the line I marked t' in my drawing. It is more difficult to find the set of events that have t'=0 (i.e. the x' axis), but the trick I used is sufficient to find them. Since we know that the speed of light is the same to all observers, we know that if the moving observer emits light to the right when his clock displays 4:59:48, and that the light is reflected by a mirror and returns to the observer when his clock displays 5:00:02, the reflection must have happened when the clock was at 5:00:00.

It is obvious from the diagram that the reflection must happen on the line marked x'. This means that this line is the x' axis, i.e. the line where t'=0. This line consists of all events that are simultaneous with the event at the origin of the diagram. This line is what the moving observer would call "space, at time t'=0".

In my drawing lines JL and MO are the same as AG and HI only they are rotated according to relativity.

You don't seem to realize that this rotation is exactly the same in non-relativistic theory. This part of what you're saying has nothing to do with relativity.

It seems pointless to comment your diagrams any further until you've understood what I'm saying about simultaneity.

I think it would help if you and Garth would go back and read Einstein’s paper.

You really have to stop assuming that you are right and everyone else is wrong. Garth, pervect and I understand special relativty. You don't. Not yet anyway, but you can learn if you listen.

I covered simultaneity in previous post please review them and let me know what you don’t understand.

I already have. It's often hard to tell if what you're saying is wrong or "not even wrong" because you sometimes don't make sense. The biggest problem is that you're implicitly assuming that what you're trying to prove is true, which is the worst mistake you could possibly make.

What would you say if I made a diagram that consists of one vertical line, and one horizontal line, that represent two spatial dimensions, and said that this diagram proves that the concepts of left and right are absolute? Would you accept that as proof? Of course not. Your proof is flawed in exactly the same way as this one that I just made up.

 

[4newton]

I think I see what your drawing is saying. You are talking about light synchronization of clocks. As shown in:
http://homepage.sunrise.ch/homepage/schatzer/space-time.html

The only problem you have is that you can have more than one light synchronized clock in the same moving frame. The many different possible clocks will not agree with each other.

If you look at my drawing GST-02 you will see that in an absolute spatial rest frame light will transition in all directions that are equal distance from the source in the same amount of time X0 to X1 or X1 back to X0 take the same amount of time. T1-T0 = T2-T1. If the light starts at X0 at 3:58 and arrives back at 4:02 then the clock is at the reflection point is 4:00.

In a moving frame X’0 the light does not transition the same path in all directions that are equal distance to the source. The time to the reflection point will be the fastest perpendicular to the direction of travel and the time to the reflection point will be the longest in the direction of travel as shown in GST-02.

The difference between a spatial rest frame X0 and a frame moving at one half the speed of light X’0 is shown in the drawing GST-02. A light path, X’0 to T’3, that is perpendicular to the direction of travel is 1.2 times longer then the path from X0 to T1. A light path that is in the direction of travel X’0 to X’1 is 1.7 times longer.

The question is; what if any is the real time.

You really have to stop assuming that you are right and everyone else is wrong. Garth, pervect and I understand special relativty. You don't. Not yet anyway, but you can learn if you listen.

I think you should consider that this cuts both ways. The laws of physics are not elected by popular vote.

I already have. It's often hard to tell if what you're saying is wrong or "not even wrong" because you sometimes don't make sense. The biggest problem is that you're implicitly assuming that what you're trying to prove is true, which is the worst mistake you could possibly make.

I don’t think you are trying to understand what I am saying. You have never questioned any particular point that you say does not make sense.

I am not trying to prove anything. I am simply trying to resolve contradictions and suppose paradoxes in theories of the universe.

You make the assumption that your understanding of the theories is absolutely correct in spite of the contradictions and paradoxes. Your solutions are that we just need to accept concepts that make no sense. How do you resolve the fact that clocks do not agree and yet you say that clocks tell real time? You assume that clock time is absolute and that all of nature must bend to match that concept.

I only look to see if there is a more global understanding of space-time that does not conflict with observation. I have posted a viewpoint based on accepted theory that resolves some of the conflicts. There is no circular logic here. The entire posting here is based on the accepted theory that the speed of light is an absolute constant and as a result the relationship of space and time is also absolute.

What would you say if I made a diagram that consists of one vertical line, and one horizontal line, that represent two spatial dimensions, and said that this diagram proves that the concepts of left and right are absolute? Would you accept that as proof? Of course not. Your proof is flawed in exactly the same way as this one that I just made up.

Not so, the difference is that even you accept that the speed of light is and absolute. And if you drew a line in your example above and said it is an absolute then you would be totally lacking if you could not show an absolute relation between the vertical and horizontal lines. You seem to be blind to seeing anything as absolute. Relativity does not mean that there are no absolute relationships.

 

[Fredrik]

The only problem you have is that you can have more than one light synchronized clock in the same moving frame. The many different possible clocks will not agree with each other.

What do you mean by "in the same moving frame"? That doesn't make any sense. Do you mean that there are events that are not in the moving frame? In that case, what do you mean by "frame"?

You make the assumption that your understanding of the theories is absolutely correct in spite of the contradictions and paradoxes.

There are no contradictions or paradoxes in SR.

Have you ever thought about what it would mean if there were? SR is just the mathematical theory of Minkowski space. If SR is logically inconsistent, then the definition of Minkowski space must be too. But Minkowski space is just \mathbb R^4 with a funny metric. The metric is just a function and couldn't possibly introduce any logical inconstencies into the theory. So if Minkowski space is inconsistent, the inconsistencies must come from the real numbers. But real numbers can be constructed from the rationals (as Dedekind cuts, or as equivalence classes of Cauchy sequences), and the rationals can be constructed from the integers. This means that if SR is inconsistent, the integers are too.

Your solutions are that we just need to accept concepts that make no sense. How do you resolve the fact that clocks do not agree and yet you say that clocks tell real time? You assume that clock time is absolute and that all of nature must bend to match that concept.

But the concepts do make sense. The theory doesn't have to be wrong just because you don't understand it.

There is no circular logic here. The entire posting here is based on the accepted theory that the speed of light is an absolute constant and as a result the relationship of space and time is also absolute.

What absolute relationship are you talking about? Would it be e.g. that the world lines of light are exactly half-way between the time axis and the space axis? Then why aren't they in your diagrams? The world line of a moving observer is his time axis. Yet you insist that space in a moving observer's frame is a horizontal line in your "absolute" diagram. If that's the case, then the world line of a light ray is closer to the time axis than to the space axis, so the speed of light in that frame can't be the same as in the "absolute" frame.

If you look at my drawing GST-02...

Let's look at your drawing... The fifth diagram is the one that interests me. I'm sure you agree that x'=0 along the upper line. On what line would you say that t'=0?

 

[4newton]

What do you mean by "in the same moving frame"? That doesn't make any sense. Do you mean that there are events that are not in the moving frame? In that case, what do you mean by frame"

http://plato.stanford.edu/entries/spacetime-iframes/

A “frame of reference” is a standard relative to which motion and rest may be measured; any set of points or objects that are at rest relative to one another enables us, in principle, to describe the relative motions of bodies. A frame of reference is therefore a purely kinematical device, for the geometrical description of motion without regard to the masses or forces involved. A dynamical account of motion leads to the idea of an “inertial frame,” or a reference frame relative to which motions have distinguished dynamical properties. For that reason an inertial frame has to be understood as a spatial reference frame together with some means of measuring time, so that uniform motions can be distinguished from accelerated motions.

The top right drawing fig. 1 (X0, X1, T0, T1, and T2) is a non-moving frame (frame with no spatial transition). I use the term moving and non-moving so it is not confused with non-inertial frames, (frames under acceleration).

The drawing fig. 4 (X’0, Z’1, T’3, and T’2) and fig. 5 (X’0, T’0, X’1, T’1, X’2 and T’2) are the lines of objects that are in the same inertial frame (moving in space at a transition equal to one half the speed of light). X’0 and T’2 are the same in both Fig. 4 and Fig. 5. Fig. 4 is the left view of Fig. 5 consistent with any engineering drawing.

There are no contradictions or paradoxes in SR.

But the concepts do make sense. The theory doesn't have to be wrong just because you don't understand it.

You have never heard of the Twin paradox? I have just given you an example of the speed of one way light clocks being different at the point of reflection in the same frame.

What absolute relationship are you talking about? Would it be e.g. that the world lines of light are exactly half-way between the time axis and the space axis? Then why aren't they in your diagrams? The world line of a moving observer is his time axis. Yet you insist that space in a moving observer's frame is a horizontal line in your "absolute" diagram. If that's the case, then the world line of a light ray is closer to the time axis than to the space axis, so the speed of light in that frame can't be the same as in the "absolute" frame.

The speed of light is constant. The relationship of the speed of light to spatial distance is always the same. The relationship of the speed of light to time is always the same. What you do, how you move, or what you think can never change that relationship. All actions of the smallest possible function occur at the same time throughout the whole universe as demonstrated in previous posts. As also demonstrated in previous posts no actions change the Now. All perceived changes are the result of viewpoint and not any change of the above relationship.

You seem unable to overcome you preset thoughts and look at things from a different viewpoint. You keep trying to look at everything from the viewpoint of an observer in a frame. The math will work no matter your viewpoint because all things are related but you need to have a relational formula for every event.

If you can open your view to a more global one it is then possible to examine the nature of other types of time keeping instruments and much more that you have never thought of.

Let's look at your drawing... The fifth diagram is the one that interests me. I'm sure you agree that x'=0 along the upper line. On what line would you say that t'=0?

I am not sure what you are asking. Maybe the above reply answers you question.

 

[Fredrik]

The link to the page that talks about frames doesn't help. I know what a frame is. But I still don't know what you mean when you say things like "you can have more than one light synchronized clock in the same moving frame". That doesn't make sense. If a physical object like a clock is "in" one frame, than it's also in all the others.

A sentence like this one would make sense: "The object has a different shape in frame A than in frame B". But a sentence like this one makes no sense: "The object is in frame A".

The drawing fig. 4 (X’0, Z’1, T’3, and T’2) and fig. 5 (X’0, T’0, X’1, T’1, X’2 and T’2) are the lines of objects that are in the same inertial frame (moving in space at a transition equal to one half the speed of light).

Here it seems that you believe that "in the same inertial frame" means "moving with the same velocity", but that would be wrong. When people (other than you) say things like "the velocity of this object in frame A is v" they don't mean that the object is any more in frame A than in frame B. They are only specifying in what frame the velocity is what they say it is, which is absolutely necessary, since the velocity (but not the presence of the object) depends on the choice of frame.

You have never heard of the Twin paradox?

The "twin paradox" is not a paradox. When SR is used correctly the result is always that the astronaut twin is younger than his brother when he gets back. I have explained why in other posts in this forum. (You should try to understand what I'm trying to explain to you in this thread before you try to understand the twin "paradox").

X’0 and T’2 are the same in both Fig. 4 and Fig. 5. Fig. 4 is the left view of Fig. 5

"The left view"?! I can only guess what you mean, because you're not making sense here either. I'm guessing that you mean that to an observer who's moving to the left in figure 4 (not drawn), the lines in figure 4 would look like in figure 5. That's not correct. The line X'0---Z'1 should be rotated counterclockwise by the same amount that the line X'0---T'2 has been rotated clockwise. This is absolutely necessary to ensure that the speed of light is the same in both frames (i.e. to both observers).

The speed of light is constant.

Yes, it's certainly not accelerating. If you mean that it's the same to all different observers, I wonder why it isn't in your diagrams. (If it's c in figure 4, it's more than that in figure 5).

The relationship of the speed of light to spatial distance is always the same. The relationship of the speed of light to time is always the same.

This is "not even wrong". (It's not clear what it means).

As also demonstrated in previous posts no actions change the Now.

You haven't demonstrated anything.

All perceived changes are the result of viewpoint and not any change of the above relationship.

I agree with that (if I understand you correctly), but all you've done is to choose an arbitrary observer's viewpoint and refuse to consider what the world looks like to any other observer. How can you talk about different viewpoints when you refuse to even consider the viewpoints of the observers you call "moving".

You seem unable to overcome you preset thoughts and look at things from a different viewpoint.

That's not true. I'm just not going to abandon a logically consistent viewpoint, completely free from paradoxes and contradictions, for one that isn't.

I am not sure what you are asking. Maybe the above reply answers you question.

No, it didn't. The reason I'm asking is that this is the most important concept in all of relativity (the one you need to understand to understand all the "paradoxes") and you don't seem to understand it.

I will ask the question again, in a different way. This time I have interpreted your figure 5 as representing the viewpoint of an observer who's moving to the left with speed v in figure 4, as the events in figure 4 occur.

Let's call the observer whose world line is the left vertical line in figure 4 "A" and the observer who's moving to the left in figure 4 (world line not drawn) "B". Suppose that observer A chooses to use the event at the lower left corner of figure 4 (where the vertical and the horizontal lines meet) as the origin of both space and time coordinates. Also suppose that B uses coordinates such that he is at x=0 all the time, and has t=0 when he passes the vertical line (in figure 4) that is the origin of spatial coordinates to A.

I would like to know which of these statements about figure 5 that you agree with, and which you disagree with.

1. The world line of observer B is a vertical line touching (T'0,X'0).
2. The world line of observer A is the line from (T'0,X'0) to (T'2,X'2).
3. Observer B's time axis (events with spatial coordinate 0 in frame B) is a vertical line touching (T'0,X'0).
4. Observer A's time axis (events with spatial coordinate 0 in frame A) is the line from (T'0,X'0) to (T'2,X'2), i.e. a line through (T'0,X'0) with slope 1/v.
5. Observer B's spatial axis (events with time coordinate 0 in frame B) is the horizontal line drawn in the figure.
6. Observer A's spatial axis (events with time coordinate 0 in frame A) is a line through (T'0,X'0) with slope v.

 

[Frigga]

The twin paradox...
Here is a real life and local example.
If you were to send your twin to Mercury for 1 Earth year, once the twin returns there would be a difference of roughly 1-3 minutes in difference in age. This may seem very small in electronic time but when you're talking larger distances it adds up rapidly and exponentially. This happens due to the speed of Mercury's orbit around the Sun and the gravitational interaction.

Age is relative...could you imagine living on Mercury(if it were possible), your life would be very very much shorter.

 

[4newton]

Fredrik:
You seem to have a lot of problems understanding some very simple ideas. I did not know that you did not know how to read engineering drawings or what front left and right views were. I now present to you a 3D view maybe this will help. See drawing GST-06.

Fig. 1 is a simple stationary spatial ring. Around the ring is a reflecting surface. A light source at A sends a pulse of light out in all directions. The light pulse strikes the ring at time t1 and is reflected back to the source. All the reflections B, C, D… arrive back at the source E.

You will note that it takes the same the same amount of time for the light to travel from the source A , t0 to the ring, at t1 as it does for the light to travel from the ring at t1 back to the source at E, t2 and that the time of travel is the same in all directions.

You can also see that the reflection is midpoint from the start of the pulse at A to the return when the source is at E.

In Fig. 2 you see the same ring as above moving in a spatial direction to the right, right is the direction of tilt. You can now see that the light pulse sent out from the source when the source is at G is not reflected until J at time t4 in the direction of travel. However the light pulse in the direction perpendicular to the direction of travel is reflected at H at time t3. The time for the light to reach the reflection of the ring varies with the longest time in the direction of travel and the shortest opposite the direction of travel. The total round trip path of the light will always be the same in all directions.

The round trip time for the light pulse will vary dependent on the velocity of the ring and approach infinity as the slope of the line, representing velocity of the ring approaches the slope of the line that is the speed of light.

The round trip time for the light pulse will be minimum when the velocity of the ring is zero. As in Fig. 1.

All physical laws remain the same in a moving frame. Or what ever you want to call it, because transition causes corresponding physical changes that compensate. A mechanical clock will slow down because all mechanical clocks are dependent on mass of their elements to keep time. It is well established that mass increases with velocity. This increase in mass and the resulting slow down of the clock is in agreement with the round trip time of light in the same frame.

All other functions behave in the same manner.

 

[4newton]

Frigga:
Fredrik seems to agree that this takes place but he does not think it is a paradox. Everyone else realizes that if SR say that all physical laws are the same in all inertial frames and that your clock is based on physical laws. Then clocks after some time in one inertial frame disagree with clocks in another inertial frame contradict the first statement. To be nice we call that a paradox. SR is right in most cases just as Newton’s laws were right. It is these small “paradoxes” that should lead us to find a more true understanding of the universe. This is just as Einstein did with Newton.

All theories are open to expansion.

 

[Garth]

In the absence of gravitational fields, i.e. curvature, SR is the appropriate theory. (So Mercury was not a good example).

The paradoxes of time, such as the Twin Paradox, are resolved by the understanding that simultaneity is also relative.

There is no paradox in the understanding that a clock in one inertial frame is observed to 'tick' at a different rate to a clock in another mutually moving inertial frame.

Things get interesting when curvature is introduced.

Garth

 

[Fredrik]

You keep ignoring the things that prove you wrong. I will make one last attempt to explain this to you 4Newton, but if you keep ignoring what's important I will not waste any more time on you.

Look at http://w1.873.comhem.se/~u87325397/4Newton.jpg . It's just the drawing you did, with a few comments. Is there anything in it that you disagree with?

(In the drawing, I'm using primes to distiguish between the coordinates used by observer A and observer B. A is using the unprimed coordinates. B is using the primed coordinates).

Do you understand that different observers will have different opinions about what the time axis is, and that this implies that they also must have different opinions about what "slice" of spacetime they should call space?

If you put the line where t'=0 and y'=0 at any other place than where I have drawn it, A and B wouldn't agree about what the speed of light is.

 

[4newton]

Fredrik:
Now we are on the same page. I have no problem with you drawing.

The point is that the one way time to reflection is different in different directions. This is a difference within the same frame. You will need to contort space a great deal to make the times come out equal.

You have two choices. You can keep the idea that clocks are absolute and modify the rest of nature to maintain consistencies or you can accept the fact that there is a more basic nature of time and that other functions of nature do not change except with applied action.

The concept I have given you simplifies the idea of space and time and has no paradoxes. It also allows you to proceed with understanding the larger universe, force, energy…

If you maintain the first choice you will have a hard time understanding anything more, as is the current problem in physics today.

 

[Fredrik]

Now we are on the same page. I have no problem with you drawing.

Are you absolutely sure that you agree with this drawing? I'm very surprised by your answer, because this is just what I've been saying all along, and you've had objections every time. (All of them were either wrong or irrelevant, and usually made no sense).

For example, you have previously said that what I'm saying is wrong because you can have more than one light synchronized clock in the same moving frame and they wouldn't agree with each other. (I can't tell if this one is wrong or irrelevant, because it doesn't make sense to me).

Why have you changed your mind? Are you sure you understand what I'm saying? One of the things I'm saying is that "space" is not the same set of events to different observers.

Haven't you been saying the exact opposite the whole time?

 

[russ_watters]

Frigga:
Fredrik seems to agree that this takes place but he does not think it is a paradox. Everyone else realizes that if SR say that all physical laws are the same in all inertial frames and that your clock is based on physical laws. Then clocks after some time in one inertial frame disagree with clocks in another inertial frame contradict the first statement. To be nice we call that a paradox. SR is right in most cases just as Newton’s laws were right. It is these small “paradoxes” that should lead us to find a more true understanding of the universe. This is just as Einstein did with Newton.

As others have said and you refuse to accept, the paradoxes are not paradoxes in SR, they are paradoxes in Newtonian physics. SR is what allows us to resolve the paradox. It should be perfectly obvious that if there is a paradox in a theory, the theory doesn't work and needs to be fixed.

And the part that you are calling the paradox is, in fact, the resolution to the paradox. The paradox is in the ages of the twins, not the way the theory reads.

 

[4newton]

Fredrik:
Either I or you or both of us have not been able to understand each other. I have another drawing to bring our current understanding together. I did not understand that you where talking about a y space line. You had that line labeled as x’.

I have now included your y-space line at the angle you show. All distances are in comparison to Fig. 1.
Line GJ is the time-distance for light to reach the ring in the forward x direction with the frame moving in the x direction. Line GH is the time-distance for the light to reach the ring in the y direction within the same frame.

The time it take the light to reach H is (t3)=(t5)/2 and in this frame moving at one half the speed of light. It is 1.2 times longer than the time in Fig. 1 AB or t1. The time it takes the light to reach J is 1.7 times longer than t1.

Clocks synchronized at G and moved to the ring before the frame is in transition may test this. All clocks being in the same frame will agree on the time. After the light reaches the ring and the clocks are stopped then the clocks can be brought together and the above times will be verified.

How does SR resolve this difference?

 

[4newton]

russ_watters:
I don’t have a disagreement with SR. I agree that SR can define time as clock time for all observers. It still is true that if you go through the two clocks experiment they will not agree. The question is, are the drawings I have presented representing reality including SR. If you think they do not please let me know where they differ.

If we can agree on the representation of reality then we can proceed to the next step.

 

[Fredrik]

I have another drawing to bring our current understanding together.

Let's not bring any more drawings into this. We should focus on the details of the one we've been discussing recently. (There's also no need to draw the y direction).

I did not understand that you where talking about a y space line. You had that line labeled as x’.

What are you talking about?! I stated very clearly that the lower green line (which is the same line that I labeled x' in another drawing) is in the t-x plane, which is perpendicular to the y axis.

The horizontal black line is the x axis. That's where the t and y coordinates are zero. (Remember that the unprimed coordinates are used by observer A). It is also the direction that observer A (if he's facing the y direction) would call "right".

The lower green line is the x' axis. That's where the t' and y' coordinates are zero. (Remember that the primed coordinates are used by observer B). It is also the direction that observer B (if he's facing the y direction) would call "right".

Note that the x and x' axes do not coincide. At event G (the origin), both observers are at the same point in space, facing the same direction (we assume, as part of the definition of the observers A and B), but an event (like a phone ringing) that's on B's right in his "now", is in observer A's future. It hasn't happened yet to A. It will happen (on his right hand side) some time in the future.

If you are at all serious about learning relativity, there's something you should know: There is no way that you will ever understand relativity without understanding this. This fact (that the x and x' axes do not coincide) is the most important fact in all of SR.

I don't know how you could misunderstand my drawing like that. I hope you will understand it now. Perhaps you had problems because you've forgotten one basic fact from geometry: If two lines intersect, there's exactly one plane that contains them both.

Do you understand this now? Do you agree that the x' axis must be where I've drawn it, or would you put it somewhere else?

 

[Fredrik]

We were talking about paradoxes earlier. A lot of people seem to have misunderstood what a paradox is, so I will try to explain it.

A paradox in a physical theory is a prediction about the outcome of an experiment that disagrees with another prediction made by the same theory. A theory that contains a paradox is logically inconsistent, and would be thrown out with the garbage. There are no paradoxes in SR. (If there were, we would probably have to throw out all of mathematics).

The "twin paradox" might seem to be a paradox of SR, but it isn't. A correct application of the theory will always yield the result that the astronaut twin is younger when he gets back. People who don't understand the theory very well might come to a different conclusion, but that's only because they are making mistakes.

 

[4newton]

Fredrik,
If you insist on only looking at the observer clock being absolute then you must change the shape of space as you have done. This of course is not correct except in the view of the moving observer. Space for all other observers has not changed. If you look at
http://physics.syr.edu/courses/modules/LIGHTCONE/LightClock/
You can see my space-time drawing in motion. As you can see this is not only just my idea of space-time. This is not basically anything new in presenting space-time and is well supported.

I think we have wasted enough time on points of view. If you can not find anything wrong, except the point of view, in my drawing representing observation then I will go on to space-time and the Big Bang.

You have not commented on the one-way speed of light being reflected at different times by the ring. I assume you have no disagreement. You have not disagreed with the fact that you can have a spatial rest frame where there is no spatial transition. This is a point that russ_watters and I had a disagreement on. Russ do we now agree that there is a spatial rest frame?

I think the idea of simultaneous events will be much clear when considered with the Big Bang.

 

[Alkatran]

http://casa.colorado.edu/~ajsh/sr/paradox.html

Read the entire site. Then click "forward to Centre of the lightcone", continue reading and moving forward, or back if necessary, until you understand why we're right (according to experiment).

 

[Garth]

http://casa.colorado.edu/~ajsh/sr/paradox.html

Read the entire site. Then click "forward to Centre of the lightcone", continue reading and moving forward, or back if necessary, until you understand why we're right (according to experiment).

Great link, thanks.

Garth

 

[russ_watters]

You have not disagreed with the fact that you can have a spatial rest frame where there is no spatial transition. This is a point that russ_watters and I had a disagreement on. Russ do we now agree that there is a spatial rest frame?

If by "spatial rest frame" you mean an absolute/universal reference frame from-which to measure all velocities, distances, and times, of course not!

 

[4newton]

These illustrations of course point up the fact that you have space with different dimensions in two different reference frames located at the same center point in space-time. In order to accept this you must discard the fact that static objects always have the same spatial difference between them regardless of your reference frame. The distance between the Earth and the sun does not change just because you are in motion.

You must abandon the idea that clocks directly tell real time. You must think of a clock as just another variable in space-time. If time is another dimension as everyone seems to claim then you must follow the rules for dimensions.

 

[Garth]

These illustrations of course point up the fact that you have space with different dimensions in two different reference frames located at the same center point in space-time. In order to accept this you must discard the fact that static objects always have the same spatial difference between them regardless of your reference frame. The distance between the Earth and the sun does not change just because you are in motion.

You must abandon the idea that clocks directly tell real time. You must think of a clock as just another variable in space-time. If time is another dimension as everyone seems to claim then you must follow the rules for dimensions.

"the same spatial distance" is in fact in SR the space-time interval, in time units this is the proper time, or the "real time" told by an inertial clock that is moving along the geodesic that joins the two events. This is invariant between "different frames". The space distance and the time interval between two events as measured in a particular frame do change "just because you are in motion", they do change when measured in different inertial frames in relative motion with each other.
You obviously haven't read the entire site Alkatran posted for us - it is standard SR, "read, mark, learn and inwardly digest".
Garth

 

[Fredrik]

If you insist on only looking at the observer clock being absolute then you must change the shape of space as you have done.

As usual it's not easy to understand how you misunderstood me this time. Are you saying that I'm treating the time on B's clock as more fundamental then A's clock? I would never do that.

I haven't changed the shape of space. Space is always a plane in 2+1 dimensional relativity. I'm just saying that different observers disagree about what plane that is. (Note that this is not a paradox).

I haven't changed space. I'm not saying that the x'-y plane is space in any objective way. The x-y plane is still "space" to A (but not to B).

You have not commented on the one-way speed of light being reflected at different times by the ring. I assume you have no disagreement.

You're just saying that if the mirror is far away it will take some time before the light reaches it. That's trivial and irrelevant.

I understand that you've been trying to say something else too, but I'm not sure what that is.

You have not disagreed with the fact that you can have a spatial rest frame where there is no spatial transition.

That sentence doesn't even make sense, but I'm guessing that you are trying to say that some objects can be stationary in some objective sense. That's not the case, so if that's what you mean, I disagree.

The distance between the Earth and the sun does not change just because you are in motion.

If you change your velocity, that will obviously not change any objective facts about the Earth and the sun, but spatial distance is not even something that can be defined in an objective way. If you measure the distance between the Earth and the sun before and after you change your velocity you will get different results. This is because you're not measuring the same thing. You're measuring two different things and calling them both "distance".

You must abandon the idea that clocks directly tell real time. You must think of a clock as just another variable in space-time.

I have probably misunderstood this, because I actually agree with it. The problem is that you think there is a "real" time. (If there's a preferred rest frame, then a clock that is stationary in that frame defines a preferred time).

Edit: At first glance, it may seem that I disagree with Garth about "real" time, but I don't. He is of course right about proper time. Proper time is invariant so it makes sense to call it "real".

It would make sense to explain the relationship between proper time, coordinate time and clock time here, but I don't have the time (no pun intended) to do it now. Perhaps tomorrow.

 

[4newton]

russ_watters

If by "spatial rest frame" you mean an absolute/universal reference frame from-which to measure all velocities, distances, and times, of course not!

That is not what I had in mind in my question. I was only thinking about transition in time without any spatial transition.

However, don’t you consider the Big Bang as the reference point for our universe?

I have been reading some of your post and it is interesting that we think alike on many points. I feel that we are coming together on more and more ideas I hope we can reach more agreements. I place great value on your viewpoints.

 

[Alkatran]

russ_watters


That is not what I had in mind in my question. I was only thinking about transition in time without any spatial transition.

However, don’t you consider the Big Bang as the reference point for our universe?

I have been reading some of your post and it is interesting that we think alike on many points. I feel that we are coming together on more and more ideas I hope we can reach more agreements. I place great value on your viewpoints.

The big bang expanded a point to the current universe. The center isn't fixed... it's everywhere (this is what I've been told).

Or think about it this way: if two people are moving at different speeds, will they measure the center to be in the same place? Chances are it doesn't matter what speed you're moving at the center stays fixed (just a guess!)

 

[russ_watters]

russ_watters

That is not what I had in mind in my question. I was only thinking about transition in time without any spatial transition.

However, don’t you consider the Big Bang as the reference point for our universe?

Yet another misunderstanding you have of what a theory in physics says: the Big Bang theory says nothing of the sort. In fact, it says exactly the opposite. Wait, this isn't all an elaborate cover for Geocentrism, is it?

 

[Fredrik]

If by "spatial rest frame" you mean an absolute/universal reference frame from-which to measure all velocities, distances, and times, of course not!

That is not what I had in mind in my question. I was only thinking about transition in time without any spatial transition.

If there is such a thing as "transition in time without any spatial transition" in any absolute sense, it would imply the existence of the absolute frame that Russ is talking about.

 

[4newton]

041117-04

If there is such a thing as "transition in time without any spatial transition" in any absolute sense, it would imply the existence of the absolute frame that Russ is talking about.

The discovery of the Big Bang requires a change or at least extensions of relationships. It is true at this time that the Big Bang is the primary reference point. We know that it happen at some location in the unknown all. We also know that it took place about 15 billion years ago. If you had a clock at the time of the BB and looked at it today it would indicate 15 billion. This number is of course just for discussion.

This is where thing get interesting. Do all clocks that move out from the BB in all directions accumulate the same time, tick at the same rate? The answer must be yes. If this were not so, accumulated time and the rate of clocks would be different through out the universe. You could have places in the universe that transitions could take place in zero time. The whole universe would be chaos.

Observation of red shift tells us that the universe is uniform and consistent and that clocks that are not in spatial transition tick at the same rates everywhere in the universe. The same atoms produce the same spectral line everywhere.

From the BB all that is the universe is expanding outward in all directions. After the formation of mass objects the expansion of all objects continued in a line normal to the expanding surface.

Space is measured and spatial transitions take place between objects in the universe. From the standpoint that you are able to measure if you are moving to or away form objects then you may maintain a point without spatial transition in our universe.

If the whole universe is in spatial transition then the only way you could tell is by measuring the one-way speed of light.

From the above you can see that it is impossible to tell the absolute position of the universe in “whatever” but you are able to reference all positions from the Big Bang and you are also able to tell change of spatial position between objects in the universe.

The BB theory is even less egocentric than SR or any other theory. It makes us realize that nature has done a lot to make us feel important in the past and now maybe we are ready to know we are very small but are still considered important for a grand purpose.

 

[Alkatran]

This is where thing get interesting. Do all clocks that move out from the BB in all directions accumulate the same time, tick at the same rate? The answer must be yes. If this were not so, accumulated time and the rate of clocks would be different through out the universe. You could have places in the universe that transitions could take place in zero time. The whole universe would be chaos.

15 billion years according to proper Earth time I think.

It is NOT THE SAME AMOUNT everywhere!

Things move relative to each other, meaning they move faster/slower through time relative to each other, meaning they haven't measured to same time from the 'beginning'. (The moon is always moving relative to us, so it is moving slower through time according to us)

 

[russ_watters]

Two things:

-4Newton, since the BB happened everywhere, you cannot use it as a reference point.

-Alkatran, its slightly more complicated than that: The expansion of space is not motion, so it doesn't cause time dilation. But there are, of course, other motions going on that do.

 

[Alkatran]

Two things:

-4Newton, since the BB happened everywhere, you cannot use it as a reference point.

-Alkatran, its slightly more complicated than that: The expansion of space is not motion, so it doesn't cause time dilation. But there are, of course, other motions going on that do.

That's what I meant. I probably gave the wrong idea by saying "everywhere"

I figured the moon example would make it clear that I meant according to different observers.

 

[Fredrik]

The discovery of the Big Bang requires a change or at least extensions of relationships. It is true at this time that the Big Bang is the primary reference point.

A lot of things are different in a spacetime that has non-zero curvature and a big bang singularity. That's why I think it's a mistake to start talking about GR now. You don't even understand the basics of SR yet. You will not be able to understand stuff like simultaneity in GR unless until you have understood it in SR.

We know that it happen at some location in the unknown all.

No it didn't. The big bang theory says that the distance between any two points on any spacelike hypersurface goes to zero as the "time after the big bang" goes to zero. It doesn't say that there was a "bang" at some point in space.

 

[4newton]

Fredrik:

A lot of things are different in a space-time that has non-zero curvature and a big bang singularity. That's why I think it's a mistake to start talking about GR now. You don't even understand the basics of SR yet. You will not be able to understand stuff like simultaneity in GR unless until you have understood it in SR.

Let me try to explain to you your position on SR.
If back in the Middle Ages I walked on to your farm and asked you about your world. You would tell me that the world is flat and that the sun goes around the earth. I would than try to explain to you that the Earth is round like a ball and is spinning. I would also tell you that the Earth is really going around the sun.

You of course would insist that I don’t know what I am talking about and that until I accepted the idea that the Earth is flat and the sun goes around the Earth I could not possibly understand the way the world works.

From your point of view on the farm you have every proof that you are right. If you can not change the mind set that there are other points of view that may be more valid then yours then you will never leave the farm.

The question is, if the view of space-time I have presented is wrong where does it disagree with observation or experiment? You have never addressed this main point. If SR and the space-time I have drawn both account for experiment and observation, which view point, should be accepted? Should we accept a view that requires conflict with logic or one that is logical on all counts?

No it didn't. The big bang theory says that the distance between any two points on any spacelike hypersurface goes to zero as the "time after the big bang" goes to zero. It doesn't say that there was a "bang" at some point in space.

Could you please describe or draw this concept. If you have trouble drawing you may find Open Office of help
http://www.openoffice.org/
The program is free and it does have a drawing function and a conversion to PFD files.

R. G.

 

[4newton]

Russ:

-4Newton, since the BB happened everywhere, you cannot use it as a reference point.

That is an interesting viewpoint. Of course the logical extension of that is that the universe is still everywhere so nothing has changed. I think it is quite logical to understand that a balloon that is not inflated occupies a different space than when inflated. You will need to explain why the universe before expansion can not be compared with the universe today.

Is space real? Is time real? Does the universe exist? If the answer to any of these questions is no then there is no reason for physics.

R.G.

 

[4newton]

Alkatran:

15 billion years according to proper Earth time I think.

It is NOT THE SAME AMOUNT everywhere!

Things move relative to each other, meaning they move faster/slower through time relative to each other, meaning they haven't measured to same time from the 'beginning'. (The moon is always moving relative to us, so it is moving slower through time according to us).

If the time is not the same everywhere what time is it right now on an object 10 billion light years away. Remember that what is taking place there right now will take 10 billion years to reach us.
R.G.

 

[Alkatran]

Alkatran:
If the time is not the same everywhere what time is it right now on an object 10 billion light years away. Remember that what is taking place there right now will take 10 billion years to reach us.
R.G.

I just told you that different observers will measure different times as having passed. How would I know the entire history of some random object 10 billion light years away? Chances are it hasn't observed the same passage of time as the stuff that made the sun.

 

[Alkatran]

Russ:
That is an interesting viewpoint. Of course the logical extension of that is that the universe is still everywhere so nothing has changed. I think it is quite logical to understand that a balloon that is not inflated occupies a different space than when inflated. You will need to explain why the universe before expansion can not be compared with the universe today.

Is space real? Is time real? Does the universe exist? If the answer to any of these questions is no then there is no reason for physics.

R.G.

Take a perfectly round sphere and show me the center of it's surface area.

That's why you can't necessarily pinpoint the center of our universe.

 

[Alkatran]

Fredrik:
Let me try to explain to you your position on SR.
If back in the Middle Ages I walked on to your farm and asked you about your world. You would tell me that the world is flat and that the sun goes around the earth. I would than try to explain to you that the Earth is round like a ball and is spinning. I would also tell you that the Earth is really going around the sun.

You of course would insist that I don’t know what I am talking about and that until I accepted the idea that the Earth is flat and the sun goes around the Earth I could not possibly understand the way the world works.

From your point of view on the farm you have every proof that you are right. If you can not change the mind set that there are other points of view that may be more valid then yours then you will never leave the farm.

The question is, if the view of space-time I have presented is wrong where does it disagree with observation or experiment? You have never addressed this main point. If SR and the space-time I have drawn both account for experiment and observation, which view point, should be accepted? Should we accept a view that requires conflict with logic or one that is logical on all counts?Could you please describe or draw this concept. If you have trouble drawing you may find Open Office of help
http://www.openoffice.org/
The program is free and it does have a drawing function and a conversion to PFD files.

R. G.

Relativity is tested everyday. If the farmer had done a scientific test, such as measuring how far the horizon was, he would realize the Earth could not be flat.

What is the space time you have drawn?

 

[russ_watters]

If you like the flat-earth analogy and want to keep us on the flat-earth side, here's the comparison: We've led you by the hand to the edge of the world and you've looked over the edge at the nothingness below and still refuse to accept that the world is flat.

SR has, for the past 80 years, passe ever test thrown at it. It has never once been found to describe the universe on the macroscopic scale inaccurately. The problem here is that you quite simply either don't understand it or understand it but refuse to accept it. Either way, the resolution to all this is entirely up to you.