Time Dilation

[geordief]

It seems to me (a very recent realization ) that simple relative movement causes observers to view the clocks in relatively moving frames to run slower.

I had (wrongly?) assumed that this property was a function of speed but I now think that relative speed merely increases the magnitude of the effect-it does not cause it.

It is simply enough for bodies or frames to be in relative motion for time dilation to be the "order of the day".

Since I would argue that everything is of necessity in relative motion ,is it fair to say that clocks will never agree but it is only the degree to which they disagree that can be determined?

Is this simply a philosophical point or does it have any practical consequences?

PS Is time dilation considered to have any applicability in the area of quantum mechanics?

Edited November 6, 2016 by geordief

[koti]

As far as I know, time dilation is a function of relative velocities. I think we have to keep "speed" away from this to avoid confusion. I too was mesmerized (and still am) when I first realized that time actualy moves at different rates depending on velocity of the moving frames. Im not sure but I think time dilation has not had its real world aplication in QM but it constantly has to be taken into account in other areas - like compensating for time dilation it in GPS satelites.

Edited November 6, 2016 by koti

[studiot]

The Schrodinger equation of quantum mechanics is an equation of motion.

 

If the motion is fast enough relativistic effects appear.

 

Paul Dirac was the first to present a version of the Schrodinger equation incorporating or corrected for these effects.

[geordief]

What about this figure of 10^-43 seconds before/after a theoretical Big Bang (or should that be "singularity"?) which is the furthest back in time we are supposed to have "looked" ?

 

Does Time Dilation come into how that number was arrived at?

 

Are we looking back at a situation we have been moving in relation to ever since ?

Edited November 6, 2016 by geordief

[swansont]

 

It seems to me (a very recent realization ) that simple relative movement causes observers to view the clocks in relatively moving frames to run slower.

I had (wrongly?) assumed that this property was a function of speed but I now think that relative speed merely increases the magnitude of the effect-it does not cause it.

 

 

If you mean cause in the mechanical sense (turning a crank causes rotation of an axle), then no, motion does not cause it. But it is the result of relative motion, so in that sense it is caused by it.

[MigL]

And why would you think we've been moving in relation to the Big Bang ?

[geordief]

And why would you think we've been moving in relation to the Big Bang ?

I meant moving "wrt the situation just after the Big Bang".

 

Well , I assumed we were moving but perhaps I am wrong . I think you may be referring to the idea that the Big Gang occurred everywhere and that does seem to take the wind out of my sails

 

"Just after the Big Bang" may be practically the same as "the Big Bang" .

[Sriman Dutta]

 

I had (wrongly?) assumed that this property was a function of speed but I now think that relative speed merely increases the magnitude of the effect-it does not cause it.

Time dilation is not a function of relative velocity, from an intuitive point of view, although mathematical formulation shows such relations.

Time dilation is caused due to the fact that the speed of light is constant for all observers.

 

Yes. Relativity can be applied in quantum levels also as a moving electron in an orbital.

[geordief]

Time dilation is not a function of relative velocity, from an intuitive point of view, although mathematical formulation shows such relations.

Time dilation is caused due to the fact that the speed of light is constant for all observers.

 

Yes. Relativity can be applied in quantum levels also as a moving electron in an orbital.

I am not sure what you mean by "from an intuitive point of view" .

 

I thought intuition was not considered to be an argument for the truth or otherwise of an observation.

 

Does a phenomenon need to have one cause ? Can time dilation be "caused by" both relative inertial motion and the invariance of the speed of light in all inertial frames?

 

Do you think there must be a "chain" of causation with the speed of light being at the top of the pyramid" (mixing metaphores.perhaps)

Edited November 8, 2016 by geordief

[Tim88]

 

It seems to me (a very recent realization ) that simple relative movement causes observers to view the clocks in relatively moving frames to run slower.

I had (wrongly?) assumed that this property was a function of speed but I now think that relative speed merely increases the magnitude of the effect-it does not cause it.

It is simply enough for bodies or frames to be in relative motion for time dilation to be the "order of the day".

Since I would argue that everything is of necessity in relative motion ,is it fair to say that clocks will never agree but it is only the degree to which they disagree that can be determined?

Is this simply a philosophical point or does it have any practical consequences?

PS Is time dilation considered to have any applicability in the area of quantum mechanics?

 

 

The direction of motion is irrelevant; it's a function of relative speed. The Lorentz transformation is chosen in the direction of the speed. It was based on that understanding that Einstein could write "It is at once apparent that this result still holds good if the clock moves from A to B in any polygonal line" in §4 of http://www.fourmilab.ch/etexts/einstein/specrel/www/

 

A practical consequence is that the clocks in GPS satellites are set to run at different rates than the "proper" rate of unadjusted clocks, such that they are in tune with the clocks on earth.

[swansont]

Time dilation is not a function of relative velocity, from an intuitive point of view, although mathematical formulation shows such relations.

Time dilation is caused due to the fact that the speed of light is constant for all observers.

 

It's both.

[Sriman Dutta]

It's both.

Hmmm.....So time dilation is CAUSED by the principle of constancy of speed of light for all observers and is MATHEMATICALLY A FUNCTION of relative velocity of the observer.

[Delta1212]

Hmmm.....So time dilation is CAUSED by the principle of constancy of speed of light for all observers and is MATHEMATICALLY A FUNCTION of relative velocity of the observer.

I'm not even sure it is correct to say that it is caused by the constancy of the speed of light. It is a consequence thereof in that it was discovered that the speed of light was constant and then the effect of time dilation was worked out as a necessary result of that.

 

However, it may be equally valid to flip it around and say that the speed of light being the same for all observers is caused by time dilation between different frames. It's all interconnected rather than being a strict cause and effect relationship.

[Sriman Dutta]

Thanks.....

[geordief]

Another misconception I had was that a clock approaching an observer would run fast and a clock moving away would run slow.

 

Is there a non mathematical way (maths are hard for me) to explain why this is so?

 

If an object approaches the observer and subsequently recedes from him are there any special properties around the point where the object is neither approaching or receding?(seems that time dilation is completely unaffected then)

 

This would be the point of nearest approach.

 

I can see that this is the point where the Doppler effect switches from increased frequency to decreased frequency . Is that all that happens?

Edited November 12, 2016 by geordief

[Janus]

Another misconception I had was that a clock approaching an observer would run fast and a clock moving away would run slow.

 

Is there a non mathematical way (maths are hard for me) to explain why this is so?

 

If an object approaches the observer and subsequently recedes from him are there any special properties around the point where the object is neither approaching or receding?(seems that time dilation is completely unaffected then)

 

This would be the point of nearest approach.

 

I can see that this is the point where the Doppler effect switches from increased frequency to decreased frequency . Is that all that happens?

A clock approaching you "appear" to run fast, But this is due to the changing distance between you and shortening of the path the light has to travel. This is the classic Doppler effect. Once you account for this, you are left with time dilation. So for example, if a clock were coming at you at 0.866 c you would see it run at 3.73 times faster than your own. However once you account for the changing propagation times, it works out that the clock is running 1/2 half as fast as your own. If it is receding you would see it run at 0.268 as fast as your own, but again, accounting for the Doppler effect, you would work out that it still runs 1/2 as fast.

 

At the point of nearest approach you will see what is called the transverse Doppler effect, which will be equal to to the Time dilation factor. In our last example that mean that the light you see coming from the clock when it was at its closest point of approach will have you seeing the clock running at 1/2 speed. "The switch-over" will happen at some point before the closest approach occurs. However, there is an extra complication. You won't see the light coming from the Clock at its moment of closest approach as actually coming from the point of closest approach. This is due to the aberration of light, which causes a shift in the direction from which the light appears to come from.

[studiot]

Nicely put, Janus. +1

[geordief]

Nicely put, Janus. +1

Yes, indeed.

[Sergei Borodinski]

Unlike mass, which we can feel, the notion of absolute time is not available to us, humans. What we call TIME is a measure of passing of physical processes, of which the clock, is an instance. Humanity used a great number of artifices to mark the passing of time: astronomy, water, pendulum. The very latest

Edited November 17, 2016 by Sergei Borodinski

[Sriman Dutta]

What is the very latest. ?

[Sergei Borodinski]

Hi Janus;

What happens when two moving frames move in opposite direction and each of the two frames moves with the speed of very close to the speed of light? Also to this point, let us say that observer on each of the frames shooting a beam of light towards receding frame. Imagining such a situation, one would reckon that relative velocity between the two frames is approaching twice the speed of light C. Yet the fundamental precept of the Relativity precludes such a possibility, asserting that no physical bodies can move with respect to each other with the speed greater than the speed of light C.

 

[studiot]

You need to add the velocities relativistically, not linearly.

 

See here

 

https://www.google.co.uk/search?q=relativistic+addition+of+velocities&hl=en-GB&gbv=2&oq=relativistic+addition+of+velocities&gs_l=heirloom-serp.3..0l5j0i22i30l5.613172.621609.0.626531.35.26.0.9.9.0.203.2825.13j12j1.26.0....0...1ac.1.34.heirloom-serp..0.35.3090.b6Y_aF-YHdQ

[geordief]

If we calculate the time dilation caused by a trip to Alpha Centauri and back , is the total amount of time dilation a function of the speed or is it simply a function of the distance traveled?

 

Would a twin snail ages by an equal amount less than its twin snail than would an astronaut aboard a rocket completing the same journey at a relativistic speed?

[Sergei Borodinski]

Thanks, Studiot;

But there is a rub, from this point of view two bodies are moving literaly with superlucent speed relative to each other while the math is saying they are not.

Let say an observer was put at a point where the two moving frames began their journey. This third person, stationary one, would have all the right to say that each frame move away from him at speed close to the speed of light, but moving observers would argue that they are not.

[studiot]

Thanks, Studiot;

But there is a rub, from this point of view two bodies are moving literaly with superlucent speed relative to each other while the math is saying they are not.

Let say an observer was put at a point where the two moving frames began their journey. This third person, stationary one, would have all the right to say that each frame move away from him at speed close to the speed of light, but moving observers would argue that they are not.

 

Since I do not have the time tonight to go through relativistic velocity addition I can only suggest ask Mordred or try to reread my links and get something more out of it.

 

Nothing is moving at superlucent speed in any inertial frame.