TIME DILATION. WHY do clocks that are

[Dale]

I cannot find any reason of why the delay will be proportional to the distance.
It makes more sense to say that it is proportional to the light shift, because the light shift represents the distance.

Your comment here does not make sense. Do you understand that a light pulse travels a distance of \Delta d = c \Delta t therefore the distance is proportional to the time and vice versa.

I cannot also imagine that the light from a moving in circle object will be red shifted.

A failure of imagination on your part does not change the facts. The light from an object moving in a circle, or tangentially to you, is red shifted. Did you not read the link I posted?

The red shift claim for circular moving object is very much like the explanation of the http://en.wikipedia.org/wiki/Ladder_paradox" ; it says that although both doors open simultaneously the ladder will see that the closer door opens first.
That's wrong, because the ladder sees the doors as light reflection and since the back door opens simultaneously with the front door, there will not be door at the back, to reflect a ligh which will travel to the lader and show a presence of a door.

Again, you are under the misapprehension that SR is about visual appearances. The light delay is accounted for. SR is about what happens after accounting for the delay due to the finite speed of light.

we will end up with two different wave lengths for same light, measured on same distance in two frames of reference.

What do you mean by this? The wave lengths are different in different frames of reference, but I am not sure what you mean by the qualifier "measured on the same distance".

 

[ghwellsjr]

ghwellsjr with the twin brothers example you better think of the speed as of velocity, because in absence of a third object the speed is irrelevant.

OK, then let the Earth be that third object and change every occurrence of "speed" to "velocity" in my previous explanations.

Now try to imagine what happens to both brothers and you'll see no difference for both of them. One of them will do the real traveling, but the other will see himself as traveling the same path with the same acceleration, speed, turning around and arriving back.

When the "brother in motion" turns back, he will keep seeing the flashes sent to him before he turned back, and some time latter he will start seeing the flashes sent after he turned around.
Same for the other brother; he will see himself as turning around some time later after the "real turn" was made from his brother.

So much of what you say is true and I don't see why you aren't grasping this simple concept: There is a big difference between what the two brothers see. A brother that actually turns around will immediately see a difference in the other brother's flash rate whereas the other brother won't see it til the pattern of flashes gets transmitted from his distant brother to him.

If you don't agree with this can you please explain where you think I'm wrong?

I do not imply limitless light speed in this example, for there is no space for such suggestion.

Good.

 

[dumbperson]

I have a question about time too.

Sorry if this is a dumb question:

if there's a moving train with a mirror in it, and an observer(guy1) inside the train shines a light into it and measures the time it takes for it to get to the mirror and come back. He will measure a shorter time than an observer(guy2) outside of the train that is standing still. So the observer(guy2) says the time goes slower inside the train because its moving, but can the observer(guy1) in the train not say that time is going slower for the guy2 because in guy1's restframe guy 2 is moving? if so can someone explain this to me?

sorry if this is a dumb question, I am just curious

 

[sisoev]

Your comment here does not make sense. Do you understand that a light pulse travels a distance of \Delta d = c \Delta t therefore the distance is proportional to the time and vice versa.

The same distance can be traveled by light sent from approaching source, from departing source or from still source. Then same distance will be covered respectively by blue, red shifted, or unchanged light.
You'll probably ask me how this change anything.

Few posts earlier I asked you the question "what do we consider as light and how do we measure its speed". One photon is not light and its speed should not represent the speed of light.
The speed of light should be represented by the frequency with which we meet every successive wave. The faster we move through the waves the faster we meet every next one thus changing the frequency, respectively the "speed of light". This way we will see that the speed of light depends on the speed of the observer and on the speed of the source.
If you accept this, the theory of relativity will start to make no sense.

Again, you are under the misapprehension that SR is about visual appearances. The light delay is accounted for. SR is about what happens after accounting for the delay due to the finite speed of light.

No, I'm not under such misapprehension, but SR should take into account that some things work only one way and no relativity can be applied to them.
The example with the two garage doors treats overlapping simultaneous events to which you cannot apply simultaneity for the simple reason that you cannot observe them as two events; you see only one of them and you should treat them as one.
The fact that you KNOW about the second event does not make it present to work with it and to apply values to it for later use.
Ignoring this will create paradoxes like the example I gave you with the two light beams from the back garage door.

What do you mean by this? The wave lengths are different in different frames of reference, but I am not sure what you mean by the qualifier "measured on the same distance".

The wave length depends on the speed of the source and it cannot be different if the distance to the observer is not changed, but please ignore this for now.

 

[sisoev]

OK, then let the Earth be that third object and change every occurrence of "speed" to "velocity" in my previous explanations.

Ha-ha :)
Sometime I also need to adjust the environment and the events to my way of thinking, and then I know that I'm somewhere wrong.

So much of what you say is true and I don't see why you aren't grasping this simple concept: There is a big difference between what the two brothers see. A brother that actually turns around will immediately see a difference in the other brother's flash rate whereas the other brother won't see it til the pattern of flashes gets transmitted from his distant brother to him.

If you don't agree with this can you please explain where you think I'm wrong?

The trick for the right comprehension is to think for both brothers as symmetrically placed for the events in time.
If the departing brother measures x distance, the other will measure it as x as well, and if one of them measure n velocity it is n for the other as well.
Both of them observe the other with the same delay since they are symmetrically placed from the point in time where the events started.

 

[Dale]

The speed of light should be represented by the frequency with which we meet every successive wave. The faster we move through the waves the faster we meet every next one thus changing the frequency, respectively the "speed of light". This way we will see that the speed of light depends on the speed of the observer and on the speed of the source.

Pure nonsense. The units are not even correct. Frequency is in units of 1/time and speed is in units of distance/time. The frequency cannot possibly be the speed of light.

If you accept this, the theory of relativity will start to make no sense.

Good thing I don't accept it then.

No, I'm not under such misapprehension, but SR should take into account that some things work only one way and no relativity can be applied to them.

There are indeed many things that are invariant under the Lorentz transform. SR does take those into account. In fact, in some sense SR is primarily the study of these invariant quantities.

The wave length depends on the speed of the source and it cannot be different if the distance to the observer is not changed, but please ignore this for now.

OK, but it is wrong.

Please study this page, you seem to be under some severe misconceptions about how things work: http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html

 

[ghwellsjr]

The trick for the right comprehension is to think for both brothers as symmetrically placed for the events in time.
If the departing brother measures x distance, the other will measure it as x as well, and if one of them measure n velocity it is n for the other as well.
Both of them observe the other with the same delay since they are symmetrically placed from the point in time where the events started.

How can you think that both brothers are symmetrically placed from the point in time where the events started when one of them is causing the event to happen (he's turning around) and the other one is observing it from afar?

 

[sisoev]

Pure nonsense. The units are not even correct. Frequency is in units of 1/time and speed is in units of distance/time. The frequency cannot possibly be the speed of light.

I said "represented" not "measured", DaleSpam

Pardon me, but the rest of your answer seams very much like a dodging.
The fact that SR takes into account "many things that are invariant under the Lorentz transform" does not answer how do you see the "overlapping simultaneous events" (the two garage doors)
Not mentioning that my note puts in doubt an important part of SR.
I guess I have to wait until someone else comes with explanation.

I can imagine how annoying a guy like me can be in the midst of a company like you guys.
Later these days I'll post a thought experiment with graphics and after your answer I'll stop bothering you :)

I wish you a great weekend :)

 

[sisoev]

How can you think that both brothers are symmetrically placed from the point in time where the events started when one of them is causing the event to happen (he's turning around and the other one is observing it from afar?

The "turning around" event has no special meaning in the experiment, ghwellsjr
It is "experienced" from the other brother the same way as the brother who executes the event. The only difference is that if the real turn is to right, the other brother sees it as to left.
Once they start approaching each other in straight line, the tings are the same.
Both of them will observe the events with the same rate ratio.

 

[Dale]

I said "represented" not "measured", DaleSpam

You will have to explain the difference and the relevance then. How do you transform from the frequency "representation" to the actual speed?

Not mentioning that my note puts in doubt an important part of SR.

The only thing in doubt is your understanding of physics.

Later these days I'll post a thought experiment with graphics

I will look forward to it. Your description of the garage door paradox is unclear, so a picture would be useful.

 

[sisoev]

You will have to explain the difference and the relevance then. How do you transform from the frequency "representation" to the actual speed?

This will come with the experiment I intend to present with graphics.

I will look forward to it. Your description of the garage door paradox is unclear, so a picture would be useful.

DaleSpam, talking to you is like talking to my teacher and I appreciate your patience. I really do.

I cannot add more to the way I see the ladder experiment.
My point is that we cannot treat an overlapping simultaneous events like a simultaneity since the light from them brings information only for one of them.
To elaborate; if the simultaneous events are aligned with the observer, there will not be light information for the back event, because it is simultaneous with the front.
We know about the back event, but we cannot deal with its light information because it is absent for us.
If we take this into account, we will see that the explanation for the ladder paradox fails.
Therefore the rod contraction is false too.
Hence, the theory of relativity stands incorrect.

 

[Dale]

The "turning around" event has no special meaning in the experiment, ghwellsjr
It is "experienced" from the other brother the same way as the brother who executes the event.

This is factually incorrect. An accelerometer carried by one brother detects the g-forces of the turnaround, and an accelerometer carried by the other does not. The frequency of the pulses from the other brother changes immediately for one brother (the same one that detects the g-forces) and not for the other. The experiences of the two brothers are not the same.

 

[Dale]

My point is that we cannot treat an overlapping simultaneous events like a simultaneity since the light from them brings information only for one of them.

What do you even mean by the phrase "overlapping simultaneous events"?

 

[sisoev]

What do you even mean by the phrase "overlapping simultaneous events"?

Aligned with the observer.

 

[Dale]

How is an event aligned with anything, let alone an observer? When I use the word "aligned" I mean that two things which have some associated direction or axis are parallel. Events do not have a direction or an axis. Do you mean something like the event is on the observer's worldline?

 

[sisoev]

How is an event aligned with anything, let alone an observer?

Well, an event is actually light information for an observer.
Now, align the light information for the two simultaneous events with the observer and you'll have the information only for the front event.

 

[Dale]

Well, an event is actually light information for an observer.

No, an event is a given place at a given time. I.e. the airplanes crashed at an altitude of 2 miles, at lattitude 45º, longitude 30º, at 3:00 pm. That is an event. The light emanating from that event forms a light cone with the origin at the event. The event is a 0-dimensional set, the light cone is a 3-dimensional set.

Now, align the light information for the two simultaneous events with the observer and you'll have the information only for the front event.

Are you simply saying something to the effect that opaque objects (like garage doors) absorb light so you lose information about things on the other side of the object? If so, then simply make the doors out of glass.

 

[sisoev]

This is factually incorrect. An accelerometer carried by one brother detects the g-forces of the turnaround, and an accelerometer carried by the other does not. The frequency of the pulses from the other brother changes immediately for one brother (the same one that detects the g-forces) and not for the other. The experiences of the two brothers are not the same.

The g-force doesn't only change the frequency of the emitted signals, but also the frequency of the perceived ones.

 

[Dale]

The g-force doesn't only change the frequency of the emitted signals, but also the frequency of the perceived ones.

Do you agree that only one of the twins measures g-forces?

 

[Denius1704]

I think he is trying to say that how can we see any light reflected from the back door (so as to give the perception of it opening later than the front door) if that said back door opened at exactly the same time as the front one. Where would the information of that back door opening be carried and how would we perceive it? That is if I'm understanding his argument correctly.

 

[sisoev]

No, an event is a given place at a given time. I.e. the airplanes crashed at an altitude of 2 miles, at lattitude 45º, longitude 30º, at 3:00 pm. That is an event. The light emanating from that event forms a light cone with the origin at the event. The event is a 0-dimensional set, the light cone is a 3-dimensional set.

No, an event is a light information.
No light information - no observation of an event.
If we don't observe an event we cannot measure its values.
You can set a values for non-observed event, like in the explanation of the ladder paradox but that holds the risk to create new paradox, and I think that SR has already enough of them ;)

Are you simply saying something to the effect that opaque objects (like garage doors) absorb light so you lose information about things on the other side of the object? If so, then simply make the doors out of glass.

What I am saying is that if you turn two book pages at once you'll see the first and the third.
Hope that this is easy enough to picture it out :)

 

[sisoev]

Do you agree that only one of the twins measures g-forces?

Yes, how couldn't I :)

 

[Denius1704]

This is factually incorrect. An accelerometer carried by one brother detects the g-forces of the turnaround, and an accelerometer carried by the other does not. The frequency of the pulses from the other brother changes immediately for one brother (the same one that detects the g-forces) and not for the other. The experiences of the two brothers are not the same.

When i suggested the example i thought we all agreed that there is no turnaround event, so what g-forces are we talking about now?

Imagine the guy from Earth was watching the one moving away and then the next second moving towards him. Why would the light need more time to reach the Earth guy all of a sudden if it was reaching him just fine until the last moment of moving away? If we are imagining an uninterrupted flow of light from the moment of departure to the moment the moving brother switches directions, i imagine the image the Earth brother would receive would be a sudden shift from the 1/2 rate to the 2 rate. And the same thing would occur for the moving brother as well, like a "mirror" as sisoev suggested.

Now, apparently my imagination is very wrong and the logic i am using as well, otherwise SR would not exist today. What i am asking for is not answers such as "you are wrong" and "well that doesn't happen because it's been accounted for", but instead to be shown where my logic breaks, at which point? I am not asking for mathematical equations, because when a client comes to me to explain to him a problem with the software i don't start talking to him in 0's and 1's, but instead i try and talk his language, the one he understands. Otherwise we will be sitting on this thread for weeks everyone saying the same things not understanding the others.

And for the sake of eliminating any kind of G-Force let's imagine both brother in space in their own respective space ships, with the moving ship being equipped with inertial dampeners (or whatever they call them in the movies these days) so that if there is ANY kind of change in acceleration it will not be felt at all by either the ship or the person in the ship.

 

[Dale]

No, an event is a light information.
No light information - no observation of an event.
If we don't observe an event we cannot measure its values.
You can set a values for non-observed event, like in the explanation of the ladder paradox but that holds the risk to create new paradox, and I think that SR has already enough of them ;)

No, this is incorrect. An event is something which happens at a given place at a given instant of time:
http://en.wikipedia.org/wiki/Event_(relativity )
http://www.colvir.net/prof/richard.beauchamp/rel-an/rela.htm
http://www.hep.uiuc.edu/home/g-gollin/relativity/p112_relativity_7.html

What I am saying is that if you turn two book pages at once you'll see the first and the third.
Hope that this is easy enough to picture it out :)

Sure, pages are opaque. No big deal, just make the garage doors partially transparent.

 

[Dale]

Yes, how couldn't I :)

Since you agree that one twin measures the g forces and the other twin does not then it is clear that the twins experience the turnaround differently. So your earlier claim is not correct:

The "turning around" event has no special meaning in the experiment, ghwellsjr
It is "experienced" from the other brother the same way as the brother who executes the event.

The brother who executes the turn experiences g forces, the other does not. It is not experienced the same way.

 

[Dale]

When i suggested the example i thought we all agreed that there is no turnaround event, so what g-forces are we talking about now?

Sorry, I thought we were talking about the standard twins paradox. If there is no turnaround/no g-forces then the twins never reunite so there is no way to unambiguously compare their ages.

Imagine the guy from Earth was watching the one moving away and then the next second moving towards him. Why would the light need more time to reach the Earth guy all of a sudden if it was reaching him just fine until the last moment of moving away? If we are imagining an uninterrupted flow of light from the moment of departure to the moment the moving brother switches directions, i imagine the image the Earth brother would receive would be a sudden shift from the 1/2 rate to the 2 rate. And the same thing would occur for the moving brother as well, like a "mirror" as sisoev suggested.

If there are no g-forces then there will be no shift in rate at all. The rate will be permanently 1/2.

Now, apparently my imagination is very wrong and the logic i am using as well, otherwise SR would not exist today. What i am asking for is not answers such as "you are wrong" and "well that doesn't happen because it's been accounted for", but instead to be shown where my logic breaks, at which point? I am not asking for mathematical equations, because when a client comes to me to explain to him a problem with the software i don't start talking to him in 0's and 1's, but instead i try and talk his language, the one he understands. Otherwise we will be sitting on this thread for weeks everyone saying the same things not understanding the others.

I think we first need to clarify what scenario we are talking about. Do you want to have two perpetually inertial observers (no reunion, no unambiguous comparison of ages, no change in signal rate, perfectly symmetrical) or do you want to have one of the twins be non-inertial (g-forces, asymmetrical)? You cannot have it both ways.

And for the sake of eliminating any kind of G-Force let's imagine both brother in space in their own respective space ships, with the moving ship being equipped with inertial dampeners (or whatever they call them in the movies these days) so that if there is ANY kind of change in acceleration it will not be felt at all by either the ship or the person in the ship.

That cannot be done in flat spacetime, and if you are struggling with the twins paradox then we definitely do not want to go to curved spacetime as that cannot be done effectively without some rather hairy math.

 

[sisoev]

No, this is incorrect. An event is something which happens at a given place at a given instant of time:
http://en.wikipedia.org/wiki/Event_(relativity )
http://www.colvir.net/prof/richard.beauchamp/rel-an/rela.htm
http://www.hep.uiuc.edu/home/g-gollin/relativity/p112_relativity_7.html

I'm not even considering reading the links :)
The argument takes philosophical turn.
We couldn't talk about given place and given time if we didn't observe the event at given place and given time.
So "given place" and "given time" are properties of known event.
It becomes known through observation.
Observation becomes such through light information delivered to conscious mind or apparatus which will deliver the recorded information for the event to a conscious mind.

Sure, pages are opaque. No big deal, just make the garage doors partially transparent.

That won't change anything, DaleSpam :)
It is not the front door that prevents you to see the delayed opening of the back door.
It is the simultaneity of the aligned with you events which does not leave information except for the front event (the one which is closed to you)

Earlier I tried to explain it with light attached to the inside of the back door.
The light turns on by a switch on the front door when it is completely open.
Since the events are simultaneous, the light will be directed down when the back door is opened.
If you insist that you'll see the front door open and the back door closed, then you'll have to see the light from the source attached on the back door (the front door is opened and switched it on).
Because we cannot have two 90 degree positioned light beams from one light source, we end up with new paradox, which does not help solving the ladder paradox.

 

[Dale]

I'm not even considering reading the links :)

You do not appear to be interested in learning physics. You seem to be a crackpot with an anti-relativity agenda. That is not permitted on this forum. If you become interested in learning relativity then I would be glad to help. If you just want an anti-relativity soapbox then I suggest sciforums instead.

The fact is that the term "event" has a clearly defined meaning in relativity and it is very distinct from the concept you are describing. The concept you are describing is called a "light cone" in relativity.

It is not the front door that prevents you to see the delayed opening of the back door.
It is the simultaneity of the aligned with you events which does not leave information except for the front event (the one which is closed to you)

How does simultaneity block the information? Simultaneity is not opaque. If the doors are transparent then the fact that they are closed doesn't stop any information.

 

[sisoev]

You do not appear to be interested in learning physics. You seem to be a crackpot with an anti-relativity agenda. That is not permitted on this forum.

If you become interested in learning relativity then I would be glad to help. If you just want an anti-relativity soapbox then I suggest sciforums instead.

That is not good attitude, DaleSpam :)
I showed gratitude and respect to you.
I can say that I'm not considering to read something only if I have enough knowledge about the subject.
You should not treat me as completely ignorant person.
I may know a little bit more than you in some fields of the science and philosophy.
Have that in mind and don't lose your nerves ;)

 

[sisoev]

How does simultaneity block the information? Simultaneity is not opaque. If the doors are transparent then the fact that they are closed doesn't stop any information.

Read again two posts back.
It appears that simultaneity is "opaque" when the events are aligned with the observer.
Comment on my explanation and I'll know how to clear it for you.