Time Dilation

[skepticalbip]

Then rephrase it for us.

Here, I'll give you a link to a more physics oriented site than Wiki. It is a dumbed down explanation for those who know diddly squat about physics.
http://www.phy.olemiss.edu/HEP/quarknet/time.html
Note the equation in red. That is a quite good definition of time dilation.

Originally Posted by skepticalbip
Time dilation has nothing to do with clocks.

I didn't say that or even suggest it.

I only said that your English sucks.

WTF? don't you even read what you post
This is what you posted:

Originally Posted by Speakpigeon
Observe that time dilatation is not the dilatation of time itself but the difference between two clocks.

I said that time dilatation is not the dilatation of time itself but the difference between two clocks.

And you are still wrong. Again, time dilation has nothing to do with clocks. Clocks are only used to measure and demonstrate the dilation... read the above for comprehension.

 

[Speakpigeon]

Here, I'll give you a link to a more physics oriented site than Wiki. It is a dumbed down explanation for those who know diddly squat about physics.
http://www.phy.olemiss.edu/HEP/quarknet/time.html
Note the equation in red. That is a quite good definition of time dilation.

I didn't say that or even suggest it.

I only said that your English sucks.

WTF? don't you even read what you post
This is what you posted:

Originally Posted by Speakpigeon
Observe that time dilatation is not the dilatation of time itself but the difference between two clocks.

I said that time dilatation is not the dilatation of time itself but the difference between two clocks.

And you are still wrong. Again, time dilation has nothing to do with clocks. Clocks are only used to measure and demonstrate the dilation... read the above for comprehension.

Yeah. Apparently the guy understands what clearly you don't:

It turns out that as an object moves with relativistic speeds a "strange" thing seems to happen to its time as observed by "us" the stationary observer (observer in an inertial reference frame)

.

The very first sentence. I put it in red since you seem to like.

So, to dumb down the significance of this, no observer can observe the slowing down of his own local time. The slowing down of time is relative to the observer. Get it?!

Probably no, you won't get it. Relative to the observer means it's not time itself that slows down, if ever there's anything actually that's time, which is doubtful.

Not me saying it. The very site you yourself linked.
EB

 

[skepticalbip]

Here, I'll give you a link to a more physics oriented site than Wiki. It is a dumbed down explanation for those who know diddly squat about physics.
http://www.phy.olemiss.edu/HEP/quarknet/time.html
Note the equation in red. That is a quite good definition of time dilation.

WTF? don't you even read what you post
This is what you posted:

I said that time dilatation is not the dilatation of time itself but the difference between two clocks.

And you are still wrong. Again, time dilation has nothing to do with clocks. Clocks are only used to measure and demonstrate the dilation... read the above for comprehension.

Yeah. Apparently the guy understands what clearly you don't:

It turns out that as an object moves with relativistic speeds a "strange" thing seems to happen to its time as observed by "us" the stationary observer (observer in an inertial reference frame)

.

The very first sentence. I put it in red since you seem to like.

So, to dumb down the significance of this, no observer can observe the slowing down of his own local time. The slowing down of time is relative to the observer. Get it?!

Probably no, you won't get it. Relative to the observer means it's not time itself that slows down, if ever there's anything actually that's time, which is doubtful.

Not me saying it. The very site you yourself linked.
EB

It seems to be a toss up as to whether you are completely lacking in reading comprehension, unable to admit how wrong you were in saying it's all about clocks, or just trolling. You really should read that link entirely for comprehension rather than scanning it for a phrase you think contradicts what I posted.

Yes time dilation is a artifact of relativity - what we observe is relative to our relative motions. But the difference is real. If it wasn't then a great deal of our technology would have to be designed quite differently.

 

[Speakpigeon]

It seems to be a toss up as to whether you are completely lacking in reading comprehension, unable to admit how wrong you were in saying it's all about clocks, or just trolling. You really should read that link entirely for comprehension rather than scanning it for a phrase you think contradicts what I posted.
Yes time dilation is a artifact of relativity - what we observe is relative to our relative motions. But the difference is real. If it wasn't then a great deal of our technology would have to be designed quite differently.

Quote me where exactly I say that the difference is not real. Go on. Make us laugh.

The question you still haven't answered is where clocks prove there is something ontologically real which would be time. And then, how a difference between two clocks proves the dilatation of this ontologically real time.

I'm wasting my time, here, really.

I asked you to prove two things to support your metaphysical claims. The reality is, you won't ever do that.

You are so biased in your judgement you don't even begin to try to understand whatever this nitwit Speakpigeon says.

What a laugh.
EB

 

[Speakpigeon]

You really should read that link entirely for comprehension rather than scanning it for a phrase you think contradicts what I posted.

For your information, I've been familiar with Special Relativity and General Relativity for something like 40 years. I also studied physics two years at university here in Paris.

And, during all that time, I never came across any bit of information that would have contradicted my interpretation.

So, you're welcome to try and explain to me how what I say is wrong. Only, you need to understand first what I say instead of misrepresenting it.

Yeah, I know, you won't, ever.
EB

 

[skepticalbip]

You really should read that link entirely for comprehension rather than scanning it for a phrase you think contradicts what I posted.

For your information, I've been familiar with Special Relativity and General Relativity for something like 40 years. I also studied physics two years at university here in Paris.

WOW!
Two years of physics before you flunked out or gave up and changed to a major that didn't require actually understanding? Color me stunned.

 

[Treedbear]

[rambling]It seems that one could say that either time slows down for one observer, or else that it speeds up for the other. The person in the space ship ages more slowly or the people back on Earth age more rapidly depending on your chosen frame of reference. It's accepted that we look at it from the relativistic reference frame. The one that doesn't experience any acceleration. But either one of them could be seen as having a velocity with respect to the other. The only reason we choose one over the other is that something (an acceleration, or change in kinetic energy) happened to the spaceship, ergo cause leads to effect. If nobody ever heard of relativity then when the ship returned to Earth the crew would be asking what the hell happened to everyone. And in fact far more had happened on the Earth. The point is it's not only relative velocity. It means nothing without referencing some particular time and place. And the only thing that matters is that the two objects are at "the same place at the same time". If two equal mass objects are accelerated in opposite directions (say by a centrally located explosion) they will both age at the same rate. If one has more mass than the other their acceleration and final velocity will be inversely proportional and therefore one will age more rapidly than the other. Leads me tho think there must be some kind of conservation law involved. Conservation of space-time, or energy-time? [/rambling]

 

[Speakpigeon]

[rambling]It seems that one could say that either time slows down for one observer, or else that it speeds up for the other. The person in the space ship ages more slowly or the people back on Earth age more rapidly depending on your chosen frame of reference. It's accepted that we look at it from the relativistic reference frame. The one that doesn't experience any acceleration. But either one of them could be seen as having a velocity with respect to the other. The only reason we choose one over the other is that something (an acceleration, or change in kinetic energy) happened to the spaceship, ergo cause leads to effect. If nobody ever heard of relativity then when the ship returned to Earth the crew would be asking what the hell happened to everyone. And in fact far more had happened on the Earth. The point is it's not only relative velocity. It means nothing without referencing some particular time and place. And the only thing that matters is that the two objects are at "the same place at the same time". If two equal mass objects are accelerated in opposite directions (say by a centrally located explosion) they will both age at the same rate. If one has more mass than the other their acceleration and final velocity will be inversely proportional and therefore one will age more rapidly than the other. Leads me tho think there must be some kind of conservation law involved. Conservation of space-time, or energy-time? [/rambling]

At constant speed, i.e. ignoring acceleration, going away and coming back is by definition symmetrical. Thus, without acceleration, the twin who goes away would come back still the same age as his twin. You could make the trip essentially a trip at constant speed for most of the time, with only two short periods both of acceleration and deceleration. So, the difference in age between the twins is all in these four periods of acceleration.

We can formalise that using three clocks, C0, C1 and C2.

C0 is assumed at rest. The other two are at constant speed relative to C0. C1 is going one way, C2 is going the opposite. When C1 comes to coincide with C0, the two clocks are synchronised. C1 then keeps going and therefore moves away from C0. After several years for example, C1 meets C2 going the other way. When they meet, C2 is synchronised with C1. Then they move appart and C2 inevitably gets to where C0 is. Guess what?
EB

 

[Speakpigeon]

Guess what?

I don't know.
EB

 

[Treedbear]

[rambling]It seems that one could say that either time slows down for one observer, or else that it speeds up for the other. The person in the space ship ages more slowly or the people back on Earth age more rapidly depending on your chosen frame of reference. It's accepted that we look at it from the relativistic reference frame. The one that doesn't experience any acceleration. But either one of them could be seen as having a velocity with respect to the other. The only reason we choose one over the other is that something (an acceleration, or change in kinetic energy) happened to the spaceship, ergo cause leads to effect. If nobody ever heard of relativity then when the ship returned to Earth the crew would be asking what the hell happened to everyone. And in fact far more had happened on the Earth. The point is it's not only relative velocity. It means nothing without referencing some particular time and place. And the only thing that matters is that the two objects are at "the same place at the same time". If two equal mass objects are accelerated in opposite directions (say by a centrally located explosion) they will both age at the same rate. If one has more mass than the other their acceleration and final velocity will be inversely proportional and therefore one will age more rapidly than the other. Leads me tho think there must be some kind of conservation law involved. Conservation of space-time, or energy-time? [/rambling]

At constant speed, i.e. ignoring acceleration, going away and coming back is by definition symmetrical. Thus, without acceleration, the twin who goes away would come back still the same age as his twin. You could make the trip essentially a trip at constant speed for most of the time, with only two short periods both of acceleration and deceleration. So, the difference in age between the twins is all in these four periods of acceleration.

But the age difference doesn't all occur during the periods of acceleration. The time differential is calculated using the velocity only. Whether the acceleration period is instantaneous or prolonged it's the resulting velocity that matters (although there is the need to integrate the velocity over the period of acceleration). And in order for there to be a return trip so that the ages can be compared the need for a period of acceleration is unavoidable.

We can formalise that using three clocks, C0, C1 and C2.

C0 is assumed at rest. The other two are at constant speed relative to C0. C1 is going one way, C2 is going the opposite. When C1 comes to coincide with C0, the two clocks are synchronised. C1 then keeps going and therefore moves away from C0. After several years for example, C1 meets C2 going the other way. When they meet, C2 is synchronised with C1. Then they move appart and C2 inevitably gets to where C0 is. Guess what?
EB

I think synchronized is the wrong word there. At the instant they are at the same location as they pass each other their experience of any event would be simultaneous. But unless the two clocks are at rest at some initial reference point and are then accelerated apart I don't see how it's possible to say time is passing slower for one than the other. Calling one C0 is a rather arbitrary way of establishing one as the reference. You have 3 clocks moving relative to each other rather than two moving relative to C0. Therefore none of them is synchronized (time passing at the same rate) with any other.

 

[Treedbear]

...
I think synchronized is the wrong word there. At the instant they are at the same location as they pass each other their experience of any event would be simultaneous. But unless the two clocks are at rest at some initial reference point and are then accelerated apart I don't see how it's possible to say time is passing slower for one than the other. Calling one C0 is a rather arbitrary way of establishing one as the reference. You have 3 clocks moving relative to each other rather than two moving relative to C0. Therefore none of them is synchronized (time passing at the same rate) with any other.

I need to clarify that. At the instant they pass each other events that occur perpendicular to the line of travel will appear to be simultaneous to both observers. As with Einstein's train vs platform vs lightning strike example any events occurring in front of or behind the observers will not appear simultaneously.

And as it says here (bolding mine):

... if the events are causally connected, precedence order is preserved in all frames of reference.

 

[Speakpigeon]

...
I think synchronized is the wrong word there. At the instant they are at the same location as they pass each other their experience of any event would be simultaneous. But unless the two clocks are at rest at some initial reference point and are then accelerated apart I don't see how it's possible to say time is passing slower for one than the other. Calling one C0 is a rather arbitrary way of establishing one as the reference. You have 3 clocks moving relative to each other rather than two moving relative to C0. Therefore none of them is synchronized (time passing at the same rate) with any other.

I need to clarify that. At the instant they pass each other events that occur perpendicular to the line of travel will appear to be simultaneous to both observers. As with Einstein's train vs platform vs lightning strike example any events occurring in front of or behind the observers will not appear simultaneously.

And as it says here (bolding mine):

... if the events are causally connected, precedence order is preserved in all frames of reference.

That's better...

"Synchronisation" is the term used by Einstein, I believe.

And it's obviously the term that applies whenever the clocks get close enough to each other.
EB

 

[Speakpigeon]

But the age difference doesn't all occur during the periods of acceleration. The time differential is calculated using the velocity only. Whether the acceleration period is instantaneous or prolonged it's the resulting velocity that matters (although there is the need to integrate the velocity over the period of acceleration). And in order for there to be a return trip so that the ages can be compared the need for a period of acceleration is unavoidable.

Sure. But my model is better.
EB