How to explain Einstein's Special theory of Relativity.

In summary, the Special Theory of Relativity explains the concept of relativity and the constant speed of light. It involves the use of Lorentz transformations to relate coordinates between different frames of reference and does away with the idea of absolute time and space. Some helpful resources for understanding this theory include specific questions and suggestions for self-study from experienced members on forums like this one, as well as illustrations and animations provided in links. It is important to note that different individuals may have varying levels of understanding and interpretation of this theory.
  • #71
Doc Al said:
That doesn't make sense. Events don't move. An event is something that happens at a specific place and time (with respect to some frame of reference).

Objects can move. Is that what you mean?
I could make a new term, like a "story", to include all continuous events relative to an object. If the object is stationary in a system, then, that object has a "stationay story" and if the object moves in the system then that object has a "moving story".

However, If LT is part of SR, then, this will not be a problem any more.

SR can let the LT portion of SR handle all "moving stories". Then the famous time dilation equation of SR can handle all "stationary stories" in the moving system. But for a "stationary story" in the stationary system people cannot use the famous time dilation equation of SR to calculate the "event period". They must use the inverse equation of it.

Or, people can simply use LT to calculate the event periods (or story periods) for all kinds of story in both systems.
 
Physics news on Phys.org
  • #72
harrylin said:
According to the LT:

1. For x1'=x2' (Δx'=0, clock at rest in S', moving in S): Δt' = Δt/γ
2. For x1=x2 (Δx=0, clock at rest in S, moving in S'): Δt' = γΔt

I think that you selected situation 1. In that situation we compare the clock readings of a clock that is moving relative to S with the readings of clocks that are rest relative to S. For simplicity you can choose that "moving" clock be positioned at O'. SR says simply what the LT say for each situation.
Yes, Einstein claimed that he proved LT so that you can say "at the beginning" SR did include LT but then SR claimed {Δt' = Δt/γ is the equation for the relation of the speed of time in two systems}. I think, after that, SR cannot claim to include LT any more.

In LT, the relation of the speed of time in two systems is not so simple, it is Δt' = γ(Δt-(vΔx/c^2)) and it is different from Δt' = Δt/γ except when x' is a constant.
 
  • #73
John Huang said:
Yes, Einstein claimed that he proved LT so that you can say "at the beginning" SR did include LT but then SR claimed {Δt' = Δt/γ is the equation for the relation of the speed of time in two systems}. I think, after that, SR cannot claim to include LT any more.

In LT, the relation of the speed of time in two systems is not so simple, it is Δt' = γ(Δt-(vΔx/c^2)) and it is different from Δt' = Δt/γ except when x' is a constant.
For the last time, LT is a part of SR
In special relativity (or, hypothetically far from all gravitational mass), clocks that are moving with respect to an inertial system of observation are measured to be running more slowly. This effect is described precisely by the Lorentz transformation.
.
And you were right about Δt' = γ(Δt-(vΔx/c^2)) but wrong about Δt' = Δt/γ. When Δx=0, Δt'=γΔt not Δt/γ. I don't understand where you got Δt' = Δt/γ. I've never seen this equation used and it seems to be what is getting in your way.
 
Last edited:
  • #74
John Huang said:
but then SR claimed {Δt' = Δt/γ is the equation for the relation of the speed of time in two systems}
Like I said before, Einstein didn't say anything about the "speed of time", that equation is intended to tell you how much time Δt elapses in the unprimed frame between two readings on a clock, if the clock itself shows an elapsed time of Δt' between those readings (so Δt' is also the time in the clock's rest frame, where Δx'=0). For example, if the readings are "10 seconds" and "15 seconds", then Δt' = 5 seconds, and in the second frame the clock is running slow so in this frame it will take a longer period of Δt = γ*5 seconds for the clock's second hand to move from 10 to 15.

Look at section 4 of Einstein's 1905 paper, where he uses t for the time elapsed on the clock in the "stationary system" and τ for the time elapsed in the "moving system" when the clock itself is at rest relative to the "moving system", i.e. the time between the two readings in clock's own rest frame, introducing the setup like this:
Further, we imagine one of the clocks which are qualified to mark the time t when at rest relatively to the stationary system, and the time τ when at rest relatively to the moving system, to be located at the origin of the co-ordinates of k, and so adjusted that it marks the time τ. What is the rate of this clock, when viewed from the stationary system?
He then goes on to show that the equation τ = t/γ describes the relation between these two times in this scenario, using the LT to derive it.

So, after having looking at that section of the 1905 paper, would you agree that Einstein was not talking about the "speed of time" but rather meant the equation Δt' = Δt/γ to apply to the time elapsed between two readings of a physical clock, as measured both in its own rest frame (where Δx'=0) and in the frame where it's moving? Would you agree that given those assumptions about what the equation is supposed to represent, Δt' = Δt/γ can be derived directly from the LT? It's easy to show why, since one of the LT equations is Δt = γ(Δt' + vΔx'/c2), so if you set Δx'=0 you are left with Δt = γΔt' or Δt' = Δt/γ.

If you disagree with any of this, please explain why you think I am mistaken about what Einstein meant, preferably pointing to a specific quote from the paper to make your case.
 
Last edited:
  • #75
tensor33 said:
And you were right about Δt' = γ(Δt-(vΔx/c^2)) but wrong about Δt' = Δt/γ. When Δx=0, Δt=γΔt not Δt/γ. I don't understand where you got Δt' = Δt/γ. I've never seen this equation used and it seems to be what is getting in your way.
It's an arbitrary matter of convention which frame to define as the clock's own rest frame, although most sources do use unprimed for the frame where the clock is at rest, you can find the occasional source that defines unprimed as the observer's frame like http://www.phy.duke.edu/courses/055/faqs/faq26/ [Broken] from a university website, it's not really "wrong" as long as you explain which frame is which.
 
Last edited by a moderator:
  • #76
John Huang said:
Yes, Einstein claimed that he proved LT so that you can say "at the beginning" SR did include LT but then SR claimed {Δt' = Δt/γ is the equation for the relation of the speed of time in two systems}. I think, after that, SR cannot claim to include LT any more.

In LT, the relation of the speed of time in two systems is not so simple, it is Δt' = γ(Δt-(vΔx/c^2)) and it is different from Δt' = Δt/γ except when x' is a constant.

I see your mistake. You are saying Δt' = Δt/γ when the equation is Δt=Δt'/γ. There is no contradiction between Δt=Δt'/γ and Δt'=γΔt. They are simply inverses. Someone correct me if I'm wrong.
 
  • #77
JesseM said:
It's an arbitrary matter of convention which frame to define as the clock's own rest frame, although most sources do use unprimed for the frame where the clock is at rest, you can find the occasional source that defines unprimed as the observer's frame like http://www.phy.duke.edu/courses/055/faqs/faq26/ [Broken] from a university website, it's not really "wrong" as long as you explain which frame is which.

But if we do define the unprimed frame as the one where the clock is at rest, wouldn't the equation Δt' = Δt/γ be incorrect?
 
Last edited by a moderator:
  • #78
tensor33 said:
I see your mistake. You are saying Δt' = Δt/γ when the equation is Δt=Δt'/γ. There is no contradiction between Δt=Δt'/γ and Δt'=γΔt. They are simply inverses. Someone correct me if I'm wrong.
I would say it's wrong that "the" time dilation is Δt=Δt'/γ rather than Δt' = Δt/γ, it all depends on which frame is chosen to be the one where the clock is at rest. If the clock is at rest in the unprimed frame the first is correct, if at rest in the primed frame the second is correct.
 
  • #79
tensor33 said:
But if we do define the unprimed frame as the one where the clock is at rest, wouldn't the equation Δt' = Δt/γ be incorrect?
Yes, in that case it would be incorrect, but John Huang hasn't specified that either is supposed to be the rest frame of a specific clock, and doesn't seem to understand that the time dilation equation is meant to deal specifically with the case of a clock at rest in one of the two frames (hopefully he will read my most recent comment to him).
 
  • #80
John Huang said:
Yes, Einstein claimed that he proved LT so that you can say "at the beginning" SR did include LT but then SR claimed {Δt' = Δt/γ is the equation for the relation of the speed of time in two systems}. I think, after that, SR cannot claim to include LT any more.

In LT, the relation of the speed of time in two systems is not so simple, it is Δt' = γ(Δt-(vΔx/c^2)) and it is different from Δt' = Δt/γ except when x' is a constant.
SR claims the different solutions for x' is a constant and for x is a constant, as I summarized in my post #64. In words those equations boil down to what Dalespam wrote in his post #55.

Do you remember where you read that wrong explanation of SR that you keep hanging on?
 
  • #81
John Huang said:
My point is a logical issue.

In above example, two systems have constant relative velocity so that the speed of time in the moving system t' and the speed of time in the stationary system t should be decided once we select the point O as the stationary point, and the O' as the moving point. Under this SPECIFIC arrangement, when we talk about a period of time for ONE SPECIFIC EVENT then we should have ONLY ONE event period Δt as recorded in the stationary system and ONLY ONE event period Δt' as recorded in the moving system.

Now, what SR claims is Δt' = Δt/γ and what LT claims is Δt' = γΔt for the ABOVE example. Logically speaking, this should not happen UNLESS γ=1, isn't it? How do you explain this logical issue?
...
You are correct that LT claims Δt' = γΔt when x=0. Here is a graph to illustrate a clock at rest at x=0. The blue dots represent ticks of the clock that occur every second:

attachment.php?attachmentid=53851&stc=1&d=1355305606.png


Now we use the LT to transform the coordinates of all the events (the 1-second ticks represented by blue dots) into the coordinates of another frame moving at 0.866c with respect to the first frame. When we do the LT, we always call the original frame the unprimed frame and the new frame the primed frame:

attachment.php?attachmentid=53852&stc=1&d=1355305606.png


Note that since the speed is 0.866c, gamma is equal to two. You can see that the first event which occurred at the time coordinate of 1 in the first frame occurs now at the time coordinate of 2 in the second frame, just like the LT formula indicates.

So far so good.

Now we want to see how to use the time dilation formula. Unlike the LT formula which applies to the coordinate times in two different frames, the time dilation formula applies to the relationship between the time (primed) on a clock compared to the coordinate time (unprimed), all in a single frame.

So let's apply the time dilation formula to the first graph where the speed of the clock is zero and gamma equals one. The formula says that the time on the clock is the same as the coordinate time and we see that because the spacing of the dots is the same as the spacing of the grid lines for the graph.

Now let's apply the time dilation formula to the second graph where the speed of the clock is 0.866 and gamma equals two. The formula says that the time on the clock will be one half of the coordinate time and we see that because the spacing of the dots is twice the spacing of the grid lines for the graph. In other words, the first dot after the origin, representing a clock time of one second occurs at a coordinate time of two seconds.

Got it?
 

Attachments

  • One object stationary.png
    One object stationary.png
    2.6 KB · Views: 667
  • One object moving.png
    One object moving.png
    3.7 KB · Views: 754
Last edited:
  • #82
tensor33 said:
For the last time, LT is a part of SR.
If I ignore the fallowing logic, then, yes, LT is part of SR.

tensor33 said:
In special relativity (or, hypothetically far from all gravitational mass), clocks that are moving with respect to an inertial system of observation are measured to be running more slowly. This effect is described precisely by the Lorentz transformation.
This is the only way SR can include LT, by CLAIMING.


tensor33 said:
And you were right about Δt' = γ(Δt-(vΔx/c^2)) but wrong about Δt' = Δt/γ. When Δx=0, Δt'=γΔt not Δt/γ. I don't understand where you got Δt' = Δt/γ. I've never seen this equation used and it seems to be what is getting in your way.
Think about it, HOW the observers in the stationary system S measure the "event period" of ONE SPECIFIC event? By the stationary clock S-CLOCK in S, right? For the observers in the moving system S', they will use the moving clock M-CLOCK to measure the "event period" of ONE SPECIFIC event. For the SPECIFIC event in the arranged situation the observers in S will measure only one "event period" Δt and for observers in S' the observers will measure only one "event period" Δt'. Am I correct?

In the SPECIFIC situation, SR states based on the relative speed "v", the relation of the speed of time should be Δt' = Δt/γ, but regarding the "event period", we should go by Δt' = γ(Δt-(vΔx/c^2)). The "event period" reflects the speed of time, isn't it?
 
  • #83
John Huang said:
If I ignore the fallowing logic, then, yes, LT is part of SR.

This is the only way SR can include LT, by CLAIMING.
Enough already. Please define what you mean by "SR".

Everyone in this thread besides you understands that SR means Special Relativity. And of course Special Relativity includes the Lorentz transformations. Any claim otherwise is just silly.

Please give your definition of "SR" in your very next post. (I am giving you the benefit of the doubt here.)
 
  • #84
John Huang said:
Think about it, HOW the observers in the stationary system S measure the "event period" of ONE SPECIFIC event? By the stationary clock S-CLOCK in S, right? For the observers in the moving system S', they will use the moving clock M-CLOCK to measure the "event period" of ONE SPECIFIC event. For the SPECIFIC event in the arranged situation the observers in S will measure only one "event period" Δt and for observers in S' the observers will measure only one "event period" Δt'. Am I correct?
Events happen at a single instant. There is no Δt for a single event, only between two events. "Event period" makes no sense.
In the SPECIFIC situation, SR states based on the relative speed "v", the relation of the speed of time should be Δt' = Δt/γ, but regarding the "event period", we should go by Δt' = γ(Δt-(vΔx/c^2)).
Once again, the Lorentz transformations apply to any time interval. So Δt' = γ(Δt-(vΔx/c^2)) is always true. Realize that that is only one of the four basic transformations; Another is Δt = γ(Δt' + (vΔx'/c^2))

The time dilation formula Δt' = Δt/γ is only true for the special case where the events happen at the same position in the primed frame and thus Δx' = 0. In words, the time dilation formula says that 'moving clocks run slow'.
The "event period" reflects the speed of time, isn't it?
No.
 
  • #85
John Huang said:
HOW the observers in the stationary system S measure the "event period" of ONE SPECIFIC event?

Doc Al said:
"Event period" makes no sense.

If you [John] don't understand the standard terminology that we use when we discuss SR, it doesn't help to make up your own terminology that we don't understand.
 
  • #86
John Huang said:
I could make a new term, like a "story", to include all continuous events relative to an object. If the object is stationary in a system, then, that object has a "stationay story" and if the object moves in the system then that object has a "moving story".

However, If LT is part of SR, then, this will not be a problem any more.

SR can let the LT portion of SR handle all "moving stories". Then the famous time dilation equation of SR can handle all "stationary stories" in the moving system. But for a "stationary story" in the stationary system people cannot use the famous time dilation equation of SR to calculate the "event period". They must use the inverse equation of it.

Or, people can simply use LT to calculate the event periods (or story periods) for all kinds of story in both systems.
This is essentially correct. The standard term for "story" is "worldline".

For pedagogical reasons my recommendation is always to follow your last suggestion which I highlighted in bold. It automatically simplifies to the time dilation equation whenever it is appropriate and it avoids accidentally using it when it is not appropriate.
 
  • #87
John Huang said:
I think, after that, SR cannot claim to include LT any more.
SR still includes the LT. A specialized simplification of a general equation does not in any way invalidate the general equation.
 
  • #88
Doc Al said:
Events happen at a single instant. There is no Δt for a single event, only between two events. "Event period" makes no sense.
Thanks for your correction. Now, I will rewrite my sentence.

How do observers everywhere in the stationary system S measure the "time period" Δt of ONE SPECIFIC SECTION of continuous events from event 1 at point A to event 2 at point B? They use the synchronized stationary clocks in S. For the observers everywhere in the moving system S', they will use the synchronized moving clocks to measure the "time period" Δt' from event 1 to event 2. Now, we have a better defined case.

There are two ways to do the measure jobs.

The easy way is to measure event time t1 and t1' for event 1 at point A and measure event time t2 and t2' for event 2 at point B. We will have Δt' = t2'-t1' and Δt = t2-t1.

The difficult way is to measure event time by assigned observers, one in S and one in S'. The simplest assginment is let them stay at origin points O and O'. Let us look at this simplest situation. Since the distances of each pair of four points A, B, O and O' could be different, we must adjust the influence of the distance. When A=B=O', it will be the situation arranged by Einstein. We will have Δt' = t2'-t1' and Δt = t2-t1.

For this SPECIFIC SET of t1,t2, t1' and t2', SR states based on the relative speed "v", the relation of the speed of time in S' and S should be Δt' = Δt/γ, but regarding the "time period", we should go by Δt' = γ(Δt-(vΔx/c^2)). Am I correct?

Doc Al said:
Once again, the Lorentz transformations apply to any time interval. So Δt' = γ(Δt-(vΔx/c^2)) is always true. Realize that that is only one of the four basic transformations; Another is Δt = γ(Δt' + (vΔx'/c^2))

The time dilation formula Δt' = Δt/γ is only true for the special case where the events happen at the same position in the primed frame and thus Δx' = 0. In words, the time dilation formula says that 'moving clocks run slow'.
Yes, "In words, the time dilation formula says that 'moving clocks run slow'." and for relative speed v, the time dilation formula Δt' = Δt/γ stands.

In Δt' = Δt/γ, Δt' is for the time period in the moving system S' of a given SECTION OF EVENTS and Δt is for the stationary system S of the same SECTION OF EVENTS.
 
  • #89
ghwellsjr said:
Got it?
Thanks.
 
  • #90
John Huang said:
Thanks for your correction. Now, I will rewrite my sentence.

How do observers everywhere in the stationary system S measure the "time period" Δt of ONE SPECIFIC SECTION of continuous events from event 1 at point A to event 2 at point B? They use the synchronized stationary clocks in S. For the observers everywhere in the moving system S', they will use the synchronized moving clocks to measure the "time period" Δt' from event 1 to event 2. Now, we have a better defined case.
That's much better defined. :smile:
There are two ways to do the measure jobs.

The easy way is to measure event time t1 and t1' for event 1 at point A and measure event time t2 and t2' for event 2 at point B. We will have Δt' = t2'-t1' and Δt = t2-t1.
The difficult way is to measure event time by assigned observers, one in S and one in S'. The simplest assginment is let them stay at origin points O and O'.
OK so you now moved on to two ways of measuring the same interval: the simplest, "local" way of measuring and the indirect or "non-local" way. SR predicts the same for both set-ups; that is necessary for consistency.
Let us look at this simplest situation. Since the distances of each pair of four points A, B, O and O' could be different, we must adjust the influence of the distance. When A=B=O', it will be the situation arranged by Einstein.
Ok, you take here the special case that Δx'=0, just as you did before - correct? And for the LT we choose O=O' at t1=0. Here's a generic sketch of it:

t1...t2
O--------------------- S
A....B

A,B
O'---------------- S'
t1'
t2'

We will have Δt' = t2'-t1' and Δt = t2-t1.

For this SPECIFIC SET of t1,t2, t1' and t2', SR states based on the relative speed "v", the relation of the speed of time in S' and S should be Δt' = Δt/γ, but regarding the "time period", we should go by Δt' = γ(Δt-(vΔx/c^2)). Am I correct? [..]
That is not correct; Δt' = γ(Δt-(vΔx/c^2)) is valid for both; and there is no difference of prediction between using local clocks or distant observers. I copy-paste my earlier reply:

1. For x1'=x2' (Δx'=0, clock at rest in S', moving in S): Δt' = Δt/γ
2. For x1=x2 (Δx=0, clock at rest in S, moving in S'): Δt' = γΔt

Once more: you selected the time period of situation 1, with x1'=x2' and thus Δx≠0.
You should find from the LT that the time period Δt' = Δt/γ for that situation, based on the relative speed v.
If that is not clear to you, please ask. :smile:
 
Last edited:
  • #91
John Huang said:
Thanks for your correction. Now, I will rewrite my sentence.

How do observers everywhere in the stationary system S measure the "time period" Δt of ONE SPECIFIC SECTION of continuous events from event 1 at point A to event 2 at point B? They use the synchronized stationary clocks in S. For the observers everywhere in the moving system S', they will use the synchronized moving clocks to measure the "time period" Δt' from event 1 to event 2. Now, we have a better defined case.
OK, that's better. But so far you've not placed any restrictions on those events.


There are two ways to do the measure jobs.

The easy way is to measure event time t1 and t1' for event 1 at point A and measure event time t2 and t2' for event 2 at point B. We will have Δt' = t2'-t1' and Δt = t2-t1.
OK. I assume by 'easy way' you mean for there to be observers in both frames at the location of the events so that they do not have to account for light travel time. Good.

The difficult way is to measure event time by assigned observers, one in S and one in S'. The simplest assginment is let them stay at origin points O and O'.
OK, these single observers must take light travel time into account when interpreting their direct observations. So what? The two methods of measuring the time intervals between those events will give the same answer. (What is your point in mentioning these "two ways"?)
Let us look at this simplest situation. Since the distances of each pair of four points A, B, O and O' could be different, we must adjust the influence of the distance. When A=B=O', it will be the situation arranged by Einstein. We will have Δt' = t2'-t1' and Δt = t2-t1.
OK, now you have restricted the pair of events to be events that take place at the same location in S'. (At least that's what I think you mean.)

For this SPECIFIC SET of t1,t2, t1' and t2', SR states based on the relative speed "v", the relation of the speed of time in S' and S should be Δt' = Δt/γ, but regarding the "time period", we should go by Δt' = γ(Δt-(vΔx/c^2)). Am I correct?
No. You are incorrect in thinking that those methods (using the time dilation formula or using the LT) yield different results.

In this particular case, you can relate the time intervals using the time dilation formula since the events take place at a single location in S'. So Δt' = Δt/γ is perfectly correct.

Or you can use the LT: Δt = γ(Δt' + (vΔx'/c^2)). Since Δx' = 0, we are back to the same result, Δt' = Δt/γ.

Yes, "In words, the time dilation formula says that 'moving clocks run slow'." and for relative speed v, the time dilation formula Δt' = Δt/γ stands.
Sure, for the simple case in question, the time dilation formula applies just fine. Of course, you get the same result by applying the full Lorentz transformation.

In Δt' = Δt/γ, Δt' is for the time period in the moving system S' of a given SECTION OF EVENTS and Δt is for the stationary system S of the same SECTION OF EVENTS.
Δt' and Δt represent the time interval between those two events as seen in different frames.

I'm still not getting what your point is. And you still seem to speak as though you think "SR" just means time dilation. There is more going on than that. What about length contraction? What about the relativity of simultaneity? Sure, in certain special cases (like the one discussed here) you can directly apply the time dilation formula. But in general you must include all three relativistic effects. And the LT does that for you automatically.
 
  • #92
harrylin said:
If that is not clear to you, please ask. :smile:
Thanks. Your point is clear.
 
  • #93
John Huang said:
Thanks. Your point is clear.
Sorry I did not mean if my point is not clear (although that is also useful to get feedback on), but if it is clear to you how to calculate it.
 
  • #94
Doc Al said:
I'm still not getting what your point is. And you still seem to speak as though you think "SR" just means time dilation. There is more going on than that. What about length contraction? What about the relativity of simultaneity? Sure, in certain special cases (like the one discussed here) you can directly apply the time dilation formula. But in general you must include all three relativistic effects. And the LT does that for you automatically.
Thanks. I will explain my point in a more spesific way. But before that, let me report what I understand about the history of SR:

1. Most physicists BELIEVED that MMX is not compatible with the Newtonian Space & Time and the Galilean Transformation (GT).

2. Mr. Lorentz SUGGESTED that we might let the moving rulers shrink 1/L(v) along the moving direction so that the distance measured in S' will expand L(v) times and the x'=x-vt ---(1) in GT will change to x'=L(v)(x-xt) ---(2). He then applied the principle of relativity to get the x=L(v)(x'+vt') ---(3) and combined (2) and (3) to derive t' = L(v)(t-(vx/c^2)) ---(4) then estabished the LT. Physicists use γ for L(v) but I like to use L(v) for γ.

3. Mr. Einstein CLAIMED that he proved LT. Then he extended the idea of ruler construction to time. He liked to let a moving clock speed up or slow down. If he let a moving clock speed up then combined with the shrinking rule the speed of an object would be measured the same in S and S', then it would be no fun at all so that he selected to let a moving clock slow down at the same rate 1/L(v), Δt' = Δt/L(v) ---(5). To make the situation even more interest, he did not use the symbol Δ to show the purpose of (5) is for the relation of speed only. Any way, he created SR in year 1905.

4. Mr. Einstein went further, ASSUMED that a clock will also slow down in a stronger gravitational field that dt=1-G(r) ---(6), G is the gravitational potential. Then he created General Relativity (GR) based on SR and (6).

5. Most physicists EXPALINED some observations and experiments to support GR and GR support SR so that SR is established in the 20th century.

I think it is the time to dig into all of the fun and interesting part of SR and eventually remove them. I think we can have fun to apply our knowledge or to make the learning of knowledge easier, but, in knowledge itself, we don't need fun and interest. All we need is to match fact with logic and math.
 
  • #95
harrylin said:
Sorry I did not mean if my point is not clear (although that is also useful to get feedback on), but if it is clear to you how to calculate it.
I will explain my understanding regarding the math of SR later.
 
  • #96
John Huang said:
3. Mr. Einstein CLAIMED that he proved LT. Then he extended the idea of ruler construction to time. He liked to let a moving clock speed up or slow down. If he let a moving clock speed up then combined with the shrinking rule the speed of an object would be measured the same in S and S', then it would be no fun at all so that he selected to let a moving clock slow down at the same rate 1/L(v), Δt' = Δt/L(v) ---(5). To make the situation even more interest, he did not use the symbol Δ to show the purpose of (5) is for the relation of speed only. Any way, he created SR in year 1905.
Einstein merely pointed out that if you consider the propagation of light to be c in any inertial state you choose and not just in one illusive inertial state referred to as the ether, then the same LT that was previously discovered to describe how clocks moving with respect to that illusive ether run slower and rulers contract along the direction of motion through that illusive ether, would also work the other way around. In other words, you can assume that any Inertial Reference Frame is just like the illusive inertial ether state and so you don't have to bother looking for that illusive inertial ether state anymore because you will never find it.
John Huang said:
I think it is the time to dig into all of the fun and interesting part of SR and eventually remove them. I think we can have fun to apply our knowledge or to make the learning of knowledge easier, but, in knowledge itself, we don't need fun and interest. All we need is to match fact with logic and math.
I think you're asking to get banned. This forum is dedicated to learning relativity, not fixing it because it's not broken. If you think it is, then it's your own misunderstanding that's broken and needs to be fixed.
 
  • #98
DaleSpam said:
You may name the best experiment you like and I will study it in more detail.

Here is my first logical issue: Two stories of Mr. Time.

Let Mr. Time in the stationary system S of LT. Mr. Time moves from a point A at time t1 to a point B at time t2. I name the case when A=B=O' as story1 and when A=B=O as story2, O and O' are origin points respectively. After observers in S' records the event time t1' and t2' we will have two results.

In the story1, LT supports SR and in the story2 LT supports anti-SR.

We are ready for my first logical issue. If LT can support SR and anti-SR in separate situations then, lopgically speaking, should we say that anti-SR and SR are equally possible solutions for the actual time formula of the nature?
 
  • #99
John Huang said:
You may name the best experiment you like and I will study it in more detail.
Any alternative theory must explain ALL of those experiments (as SR does), not just one.

John Huang said:
Here is my first logical issue: Two stories of Mr. Time.

Let Mr. Time in the stationary system S of LT. Mr. Time moves from a point A at time t1 to a point B at time t2. I name the case when A=B=O' as story1 and when A=B=O as story2, O and O' are origin points respectively. After observers in S' records the event time t1' and t2' we will have two results.

In the story1, LT supports SR and in the story2 LT supports anti-SR.
Nonsense. SR uses the LT to determine the answer in both cases. Any contradiction is entirely a figment of your imagination.

John Huang said:
We are ready for my first logical issue. If LT can support SR and anti-SR in separate situations then, lopgically speaking, should we say that anti-SR and SR are equally possible solutions for the actual time formula of the nature?
No, you are simply confused, despite having been corrected on this point numerous times. Your logical arguments are not arguments against SR, they are arguments against some strawman distorted theory of your own imagining.

In honor of its inventor I name this theory you are discussing "John Huang Theory" (JHT). JHT obviously has problems, as acknowledged by its inventor.
 
  • #100
ghwellsjr said:
This forum is dedicated to learning relativity, not fixing it because it's not broken. If you think it is, then it's your own misunderstanding that's broken and needs to be fixed.
That is my purpose here to fix my misunderstanding.
 
  • #101
DaleSpam said:
Any alternative theory must explain ALL of those experiments (as SR does), not just one.
Please just show me one experiment and explain it briefly why it is a good one. I will spend time on it. Thanks.

DaleSpam said:
Nonsense. SR uses the LT to determine the answer in both cases. Any contradiction is entirely a figment of your imagination.
Sorry, I should make the event1 and event 2 easy to recognize, I will let Mr. Time do something at event 1 and event 2 as following:

Here is my first logical issue: Two stories of Mr. Time.

Let Mr. Time in the stationary system S of LT. Mr. Time points his forefinger upward and moves from a point A at time t1 to a point B at time t2 and curls his forefinger. I name the case when A=B=O' as story1 and when A=B=O as story2, O and O' are origin points respectively. After observers in S' records the event time t1' and t2' we will have two results.

In the story1, LT supports SR and in the story2 LT supports anti-SR.
 
  • #102
John Huang said:
Please just show me one experiment and explain it briefly why it is a good one. I will spend time on it. Thanks.
They are all good, you should spend time on each. At a minimum you need to understand Michelson-Morely, Ives-Stillwell, and Kennedy-Thorndike.

John Huang said:
In the story1, LT supports SR and in the story2 LT supports anti-SR.
LT always supports SR.

In the story1, LT supports JHT and in the story2 LT supports anti-JHT. JHT has some serious problems.
 
  • #103
John Huang said:
Sorry, I should make the event1 and event 2 easy to recognize, I will let Mr. Time do something at event 1 and event 2 as following:

Here is my first logical issue: Two stories of Mr. Time.

Let Mr. Time in the stationary system S of LT. Mr. Time points his forefinger upward and moves from a point A at time t1 to a point B at time t2 and curls his forefinger. I name the case when A=B=O' as story1 and when A=B=O as story2, O and O' are origin points respectively. After observers in S' records the event time t1' and t2' we will have two results.

In the story1, LT supports SR and in the story2 LT supports anti-SR.
As far as I can tell, the example and explanation that I gave you in post #81 at the top of the previous page would fit in nicely with your two stories, the first diagram applying to story2 and the second diagram applying to story1. In the frame in which Mr. Time is stationary, the first diagram, event 1 is at the coordinate time of 1 second which is also the Proper Time on Mr. Time's clock. Event 2 is at the coordinate time of 2 seconds, the same as the time on Mr. Time's clock. Here is the first graph of story2 with annotations:

attachment.php?attachmentid=53954&stc=1&d=1355557806.png


Now we use the Lorentz Transformation process on both of the events to determine their coordinates in a new frame moving at 0.866c with respect to the first frame. This gives us story1:

attachment.php?attachmentid=53955&stc=1&d=1355557806.png


You will note that in this frame the coordinate times for Mr. Time's clock are double what they were for story2. I don't see any problem with SR or LT.

When you read my previous post and I asked you if you got it, you said Thanks, implying that you understood it. But now you're asking the same question all over again, implying that you didn't get it.

Rather than continue on like this, please tell me what you are having problems with in my explanation on post #81. I tried to address all of your concerns.
 

Attachments

  • One object stat with events.PNG
    One object stat with events.PNG
    3.1 KB · Views: 450
  • One object move with events.PNG
    One object move with events.PNG
    4.2 KB · Views: 495
  • #104
ghwellsjr said:
When you read my previous post and I asked you if you got it, you said Thanks, implying that you understood it. But now you're asking the same question all over again, implying that you didn't get it.

Rather than continue on like this, please tell me what you are having problems with in my explanation on post #81. I tried to address all of your concerns.
I knew that you tried to help. That is why I thanked you.

I also know your solution to the SR and anti-SR issue. You let the clock stay at event point. I think it is just a tool you used to work around the issue. As a matter of fact, clocks are with observers in S and S', not with the event. I think your answer to my first logic question is not good but I appreciate your help. Thanks again.
 
  • #105
John Huang said:
I knew that you tried to help. That is why I thanked you.

I also know your solution to the SR and anti-SR issue. You let the clock stay at event point. I think it is just a tool you used to work around the issue. As a matter of fact, clocks are with observers in S and S', not with the event. I think your answer to my first logic question is not good but I appreciate your help. Thanks again.
Mr. Time is present at both events along with his clock in both IRF's. What other observers are you considering and where are they?
 
<h2>1. What is Einstein's Special Theory of Relativity?</h2><p>Einstein's Special Theory of Relativity is a scientific theory developed by Albert Einstein in 1905. It is based on two main principles: the laws of physics are the same for all observers in uniform motion, and the speed of light is constant for all observers regardless of their relative motion.</p><h2>2. How does Einstein's Special Theory of Relativity differ from Newton's laws of motion?</h2><p>Einstein's theory differs from Newton's laws of motion in several ways. Firstly, it takes into account the constant speed of light and how it is the same for all observers, while Newton's laws do not. Secondly, it introduces the concept of space-time, where time and space are intertwined, while Newton's laws treat time and space as separate entities. Lastly, Einstein's theory predicts that time and space are relative, depending on the observer's frame of reference, while Newton's laws assume time and space are absolute.</p><h2>3. Can you provide a simple explanation of the famous equation E=mc² in relation to Special Relativity?</h2><p>E=mc² is an equation that represents the relationship between energy (E), mass (m), and the speed of light (c). It was derived by Einstein in his Special Theory of Relativity and shows that energy and mass are interchangeable. This means that a small amount of mass can be converted into a large amount of energy, and vice versa. It also shows that the speed of light is a fundamental limit in the universe.</p><h2>4. How does Special Relativity impact our understanding of time and space?</h2><p>Einstein's Special Theory of Relativity revolutionized our understanding of time and space. It introduced the concept of space-time, where time and space are interconnected, and both are relative to the observer's frame of reference. This means that the perception of time and space can differ for different observers depending on their relative motion. It also showed that time and space can be affected by gravity, leading to the theory of General Relativity.</p><h2>5. Is Special Relativity still relevant in modern science?</h2><p>Yes, Special Relativity is still a fundamental theory in modern science. It has been extensively tested and verified through experiments and observations, and it is used in many fields such as astrophysics, particle physics, and cosmology. It has also led to the development of technologies such as GPS and particle accelerators. While it has been expanded upon by General Relativity, Special Relativity remains a crucial part of our understanding of the universe.</p>

1. What is Einstein's Special Theory of Relativity?

Einstein's Special Theory of Relativity is a scientific theory developed by Albert Einstein in 1905. It is based on two main principles: the laws of physics are the same for all observers in uniform motion, and the speed of light is constant for all observers regardless of their relative motion.

2. How does Einstein's Special Theory of Relativity differ from Newton's laws of motion?

Einstein's theory differs from Newton's laws of motion in several ways. Firstly, it takes into account the constant speed of light and how it is the same for all observers, while Newton's laws do not. Secondly, it introduces the concept of space-time, where time and space are intertwined, while Newton's laws treat time and space as separate entities. Lastly, Einstein's theory predicts that time and space are relative, depending on the observer's frame of reference, while Newton's laws assume time and space are absolute.

3. Can you provide a simple explanation of the famous equation E=mc² in relation to Special Relativity?

E=mc² is an equation that represents the relationship between energy (E), mass (m), and the speed of light (c). It was derived by Einstein in his Special Theory of Relativity and shows that energy and mass are interchangeable. This means that a small amount of mass can be converted into a large amount of energy, and vice versa. It also shows that the speed of light is a fundamental limit in the universe.

4. How does Special Relativity impact our understanding of time and space?

Einstein's Special Theory of Relativity revolutionized our understanding of time and space. It introduced the concept of space-time, where time and space are interconnected, and both are relative to the observer's frame of reference. This means that the perception of time and space can differ for different observers depending on their relative motion. It also showed that time and space can be affected by gravity, leading to the theory of General Relativity.

5. Is Special Relativity still relevant in modern science?

Yes, Special Relativity is still a fundamental theory in modern science. It has been extensively tested and verified through experiments and observations, and it is used in many fields such as astrophysics, particle physics, and cosmology. It has also led to the development of technologies such as GPS and particle accelerators. While it has been expanded upon by General Relativity, Special Relativity remains a crucial part of our understanding of the universe.

Similar threads

  • Special and General Relativity
Replies
10
Views
685
Replies
6
Views
703
  • Special and General Relativity
Replies
19
Views
2K
  • Special and General Relativity
Replies
27
Views
601
  • Special and General Relativity
Replies
15
Views
754
  • Special and General Relativity
2
Replies
61
Views
3K
  • Special and General Relativity
Replies
7
Views
1K
  • Special and General Relativity
Replies
11
Views
941
  • Special and General Relativity
Replies
10
Views
402
  • Special and General Relativity
Replies
15
Views
1K
Back
Top