Does Lorentz contraction affect a stationary object that you pass at high speed?

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Offline LeeE

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I just don't like the thought of it. It just seems wrong. I want to punch it.

Lol

Try thinking in terms of that summed-vector view I've mentioned in a couple of threads.  In that interpretation, everything is always traveling at 'c'.  However, that constant speed of 'c' is a sum of two vectors and while the product of the two vectors is an absolute, the individual vectors, representing space and time, aren't.  Space and time then, can be any value, as long as they sum to the absolute value 'c'.  I think that what makes this counter-intuitive is that it seems the other way around to us; it is space and time that appear to be constant, which it is, but only from our point of view, which is dictated by the summed vector.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline lightarrow

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Alberto - I'm just getting more confused now.

Look at this quote:

The lenght contraction means that you could arrive there in a few seconds, and, furthermore, that light from a distant source beyond the limit will have to cover a less distance to reach us, but we couldn't see past it from the beginning, we should wait to meet the light (emitted from the distant source) at ~ half journey.

Your reply states (where I've highlighted it) that the distance would be less yet now you are saying that it is the way that distance is measured that makes it seem less:

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it's not a "real" contraction in the sense that there is no internal tension; you could think of it as an "artefact" of how we *define* distance between two points
I put the word "artefact" in commas because it's not a real artefact, but the reality; Writing that way I just wanted to point out that it's a relativistic effect, that is it's due to how we define distance, which depends on the frame of reference. Maybe it's this that you aren't grasping: our definition of distance is frame-dependent, it's not an *intrinsic* property of bodies or of space.
« Last Edit: 26/03/2009 19:38:11 by lightarrow »

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Offline DoctorBeaver

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Alberto - I'm just getting more confused now.

Look at this quote:

The lenght contraction means that you could arrive there in a few seconds, and, furthermore, that light from a distant source beyond the limit will have to cover a less distance to reach us, but we couldn't see past it from the beginning, we should wait to meet the light (emitted from the distant source) at ~ half journey.

Your reply states (where I've highlighted it) that the distance would be less yet now you are saying that it is the way that distance is measured that makes it seem less:

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it's not a "real" contraction in the sense that there is no internal tension; you could think of it as an "artefact" of how we *define* distance between two points
I put the word "artefact" in commas because it's not a real artefact, but the reality; Writing that way I just wanted to point out that it's a relativistic effect, that is it's due to how we define distance, which depends on the frame of reference. Maybe it's this that you aren't grasping: our definition of distance is frame-dependent, it's not an *intrinsic* property of bodies or of space.


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Offline DoctorBeaver

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Let me go away & have a think.
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Offline LeeE

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I want my mummy!

I always loved the Rolf Harris version of that song  [:D]
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline yor_on

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If 'distance' is a property of 'frames', where are we?
Once 'we' were an idea inside a cave looking out. Now we are 'out' of that cave, but we still need to define what 'distance' is. If we can't define 'rest', and can't define 'distance', as anything more than a relation between 'two frames of reference' we shouldn't expect space to have any recognizable' property's except those we need to define ourselves in it :) And that, in fact, just create the same dilemma as when we once saw the the sun as movóng around us.

So, what conclusions can we draw from this statement? Only this, that what we can test by repeatable experiments under controllable circumstances will be the 'inclinations' toward what spacetime possibly is. That doesn't say that we can't speculate, it just mean that spacetime seems like something not applicable to Newtonian standards, and that means those 'standards' that we see as applying 'locally' macroscopically for us.

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Offline Vern

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Quote from: yor_on
So, what conclusions can we draw from this statement? Only this, that what we can test by repeatable experiments under controllable circumstances will be the 'inclinations' toward what spacetime possibly is.
IMHO this is about as close as we can get to reality. We can measure and guess. And if we continue as in the past; we will guess wrong the first few times. [:)]

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Offline LeeE

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I would define 'distance' as: The measure of difference between two values.

The actual distance measured can be dependent upon upon your frame of reference though, so two different frames of reference may measure two different distances.

I think that part of the problem we're discussing is that it's impossible to measure what we're trying to measure in the way that we're trying to measure it.  For example, if we measured the length of something in terms of the angular difference between it's two ends, it's length would vary according to how far away it was from us; "These are small... but the ones out there are far away. Small... far away... ah forget it!" - Father Ted
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline DoctorBeaver

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"These are small... but the ones out there are far away. Small... far away... ah forget it!" - Father Ted

Classic!  [:D]
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Offline lightarrow

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I would define 'distance' as: The measure of difference between two values.
...of positions, measured *simultaneously*.

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Offline Vern

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I'm still wrestling with the concept of Lorentz space-time vs Einstein's SR. Now I see how the length of a stationary object must be contracted when moving past it even with the Lorentz version. I forgot that time is also dilated for the moving vessel. That means it would pass the stationary vessel in less time, and so would measure its length as contracted. So the situation is the same.

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Offline LeeE

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I would define 'distance' as: The measure of difference between two values.
...of positions, measured *simultaneously*.

Ah - no.  In any measurement, a difference is a difference.  And that's what it really comes down to; we can move stuff around, to make the difference look different, from different points of view, but at the end of the day there's a difference that needs to be accounted for.  You can't just shrug it off as imaginary.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline yor_on

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That is the 'funny' thing about it, ain't it? It's a 'difference of positions, measured simultaneously.' we are used to see 'distance' as something needing only one observer to be 'true'. LeeE described 'father Ted' here :)

Still, that ain't the whole 'truth' as i see it, as long as we have a 'depth perspective' to measure something in we trust in that, what I see and what you see, if different, will be explainable as consisting of being measured from different distances. But that has nothing to do with Lorentz contraction as I see it.

If it is a 'real' situation with length being dependent on the relative motion as measured between two 'frames of reference' then distance is a questionable thing to me.
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Offline LeeE

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Perspective only works in flat space.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline lightarrow

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I would define 'distance' as: The measure of difference between two values.
...of positions, measured *simultaneously*.

Ah - no.  In any measurement, a difference is a difference.  And that's what it really comes down to; we can move stuff around, to make the difference look different, from different points of view, but at the end of the day there's a difference that needs to be accounted for.  You can't just shrug it off as imaginary.
Sorry, but I haven't grasped what you mean.

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Offline yor_on

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Just me thinking of the analogue with 'father Ted' :)
I see Lorenz contraction as something different than angular problems of distance. To me it questions the whole idea of 'distance' whatsoever if it is real.
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Offline lightarrow

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What I mean is that it's impossible to define "distance" without using the concept of time, and time, we now know, is frame-dependent.

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Offline yor_on

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You introduce a interesting question there Lightarrow.
Can one isolate f ex. time from 'spacetime' and say that it is time that change the measurements?
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Offline LeeE

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What I mean is that it's impossible to define "distance" without using the concept of time, and time, we now know, is frame-dependent.

Spatial distance can be defined without needing to reference temporal distance.  In practical terms, we can't measure a spatial distance because we need time within which to function, but measuring isn't the same as defining.  For example, consider a 30 cm long rule; unless something happens to change that rule, it will always be 30 cm long and that distance will not vary over time.  However, it may measured as being a different length depending on the frame of the measuring observer.

The difference between the observed relativistic temporal and spatial effects when such an object closely approaches a BH and then returns to a distant observer are that the spatial length can be reconciled but the temporal durations can't i.e. the ruler is the same length as it was before, but it's now younger than the observer.  Hmm...  have I crossed topics here?
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline lightarrow

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What I mean is that it's impossible to define "distance" without using the concept of time, and time, we now know, is frame-dependent.

Spatial distance can be defined without needing to reference temporal distance.  In practical terms, we can't measure a spatial distance because we need time within which to function, but measuring isn't the same as defining.  For example, consider a 30 cm long rule; unless something happens to change that rule, it will always be 30 cm long and that distance will not vary over time.  However, it may measured as being a different length depending on the frame of the measuring observer.
As to say: "it's red, unless it isn't"  [:)]
To define distance you have to measure positions of points at specific times; imagine a spring which is slowly extending: now it's 1 metre long, after 1 hour is 1.001 metres, ecc. Which is its lenght? You can't avoid using the concept of time.

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Offline yor_on

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Some statements, you tell me if and where you disagree :)

The universe have general macroscopic properties as 'Time' and three 'spatial dimensions'. Inside them we find matter and vacuum and light. Matter and vacuum (space) are defined in/as density and distance. A perfect vacuum is defined as containing no matter nor mass nor density. Distance is defined as being a property relating to what frames of reference we use to compare and measure it with.

Light is measured as a invariant velocity in a vacuum over a certain distance in time. It is also thought to consist of 'light quanta' of a invariant energy amount. Light will always be 'time less' no matter how much it is 'slowed down' as seen from another frame of reference. It is also seen as a 'duality' in that we have experiments proving it to act as a particle as well as waves. Photons in QED (Quantum Electro Dynamics) are seen as both 'real' photons existing in a continuum in measurable time (Sun Earth) and as 'virtual' photons 'surrounding' atoms and outside measurable time.

Those virtual photons is expected to be responsible for the forces of electricity and magnetism. and also (?) seem to be the carriers of all other 'communication' between particles? A perfect Vacuum, although empty of 'matter', have a hidden 'energy' as well as consisting of virtual particles. Those interact with our macroscopic spacetime although they themselves are of to short duration to become measurable according to HUP (Heisenberg's Uncertainty Principle) and Planck time. So what do we have?

Light/photons/waves acting in a twofold manner, as measurable light and as unmeasurable light, 'timeless' internally but obeying spacetimes geodesics and able to act 'in time' on our universe, existing as a needful property for both living as well as dead matter. A vacuum devoid of matter (if perfect) but not of energy and virtual particles, and also containing 'distances'. Matter which I 'split' in two parts, 'living' and 'dead'.

So what else have I forgotten here?
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Offline LeeE

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What I mean is that it's impossible to define "distance" without using the concept of time, and time, we now know, is frame-dependent.

Spatial distance can be defined without needing to reference temporal distance.  In practical terms, we can't measure a spatial distance because we need time within which to function, but measuring isn't the same as defining.  For example, consider a 30 cm long rule; unless something happens to change that rule, it will always be 30 cm long and that distance will not vary over time.  However, it may measured as being a different length depending on the frame of the measuring observer.
As to say: "it's red, unless it isn't"  [:)]
To define distance you have to measure positions of points at specific times; imagine a spring which is slowly extending: now it's 1 metre long, after 1 hour is 1.001 metres, ecc. Which is its lenght? You can't avoid using the concept of time.

I can't quite see what point you're trying to make here.

You've quoted me as saying "Spatial distance can be defined without needing to reference temporal distance.  In practical terms, we can't measure a spatial distance because we need time within which to function, but measuring isn't the same as defining", which I thought made the difference between defining and measuring pretty clear, but then you say "To define distance you have to measure positions of points at specific times", which is just plain incorrect; you can define something without needing to measure it.  If I define something to be 30cm long then measuring it is redundant - it is by definition 30cm long.

I also don't understand why you've also highlighted the next bit of text where I say "For example, consider a 30 cm long rule; unless something happens to change that rule, it will always be 30 cm long and that distance will not vary over time" and then go on to talk about a spring that is explicitly changing over time: how is it relevant to compare something that explicitly doesn't change over time with something that explicitly does?

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You can't avoid using the concept of time

The concept of time?  Well, I guess that with something that doesn't change over time, the concept of time is relevant, but only by virtue of time being specifically excluded as a factor.

When a state changes, yes, time is a factor, but where there is no change of state time is not a factor because the state is constant and there is no change of state over time;  any formula that tries to link the state S with time t isn't going to work because a change in t is not reflected by a change in S.  Indeed, in any such formula, t must be meaningless for any value of t if S is to remain unchanged.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline lightarrow

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Can you *define* a spatial distance to be 30 cm long, without having to make a measurement? Are you talking about physics or about philosophy?
« Last Edit: 31/03/2009 18:53:40 by lightarrow »

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Offline LeeE

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Can you *define* a spatial distance to be 30 cm long, without having to make a measurement? Are you talking about physics or about philosophy?

Physics is a sub-set of philosophy and at the level we're discussing physics, dealing with abstracts is part of the deal.  Are you discussing engineering or physics?
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline lightarrow

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Can you *define* a spatial distance to be 30 cm long, without having to make a measurement? Are you talking about physics or about philosophy?

Physics is a sub-set of philosophy and at the level we're discussing physics, dealing with abstracts is part of the deal.  Are you discussing engineering or physics?
Can you show me a (serious) book of physics where it's written that you can *define* a distance between two points without having to measure it, apart the sample metre, of course?
« Last Edit: 31/03/2009 19:23:48 by lightarrow »

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Offline lightarrow

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Some statements, you tell me if and where you disagree :)

The universe have general macroscopic properties as 'Time' and three 'spatial dimensions'. Inside them we find matter and vacuum and light. Matter and vacuum (space) are defined in/as density and distance. A perfect vacuum is defined as containing no matter nor mass nor density. Distance is defined as being a property relating to what frames of reference we use to compare and measure it with.

Light is measured as a invariant velocity in a vacuum over a certain distance in time. It is also thought to consist of 'light quanta' of a invariant energy amount. Light will always be 'time less' no matter how much it is 'slowed down' as seen from another frame of reference. It is also seen as a 'duality' in that we have experiments proving it to act as a particle as well as waves.
I essentially agree up to here.

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Photons in QED (Quantum Electro Dynamics) are seen as both 'real' photons existing in a continuum in measurable time (Sun Earth) and as 'virtual' photons 'surrounding' atoms and outside measurable time.
Many people says virtual particles are nothing more than a mathematical tool in quantum fields theory and so we shouldn't think of them as really existing.

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Those virtual photons is expected to be responsible for the forces of electricity and magnetism. and also (?) seem to be the carriers of all other 'communication' between particles? A perfect Vacuum, although empty of 'matter', have a hidden 'energy' as well as consisting of virtual particles. Those interact with our macroscopic spacetime although they themselves are of to short duration to become measurable according to HUP (Heisenberg's Uncertainty Principle) and Planck time.
The problem is not much of HUP but of the fact that virtual particles are "out of shell" that is don't obey E2 = (mc2)2 + (cp)2

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So what do we have?

Light/photons/waves acting in a twofold manner, as measurable light and as unmeasurable light, 'timeless' internally but obeying spacetimes geodesics and able to act 'in time' on our universe, existing as a needful property for both living as well as dead matter. A vacuum devoid of matter (if perfect) but not of energy and virtual particles, and also containing 'distances'. Matter which I 'split' in two parts, 'living' and 'dead'.

So what else have I forgotten here?
Billions of things that we'll discover in the (near or far) future...  [:)]

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Offline Vern

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Quote from: lightarrow
Many people says virtual particles are nothing more than a mathematical tool in quantum fields theory and so we shouldn't think of them as really existing.
I think this is a very good observation and predict that it will eventually be the accepted hypothesis.

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Offline yor_on

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Lightarrow, when I write "Those interact with our macroscopic spacetime although they themselves are of to short duration to become measurable according to HUP (Heisenberg's Uncertainty Principle) and Planck time." you say that it hasn't to do with HUP? They are as you say 'out of shell', if you by that mean 'virtual', not being 'consistent in time'? To me it is HUP that best describes it, that and them possibly being 'under' Planck's definitions.
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Offline lightarrow

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Lightarrow, when I write "Those interact with our macroscopic spacetime although they themselves are of to short duration to become measurable according to HUP (Heisenberg's Uncertainty Principle) and Planck time." you say that it hasn't to do with HUP? They are as you say 'out of shell', if you by that mean 'virtual', not being 'consistent in time'? To me it is HUP that best describes it, that and them possibly being 'under' Planck's definitions.
Virtual particles are not such because they have a too short life, but because they don't obey the equation I wrote in my previous post. It's theyr existence which is allowed by HUP; the property of "being virtual" is "not-obeying that equation".
« Last Edit: 01/04/2009 20:41:45 by lightarrow »

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Offline yor_on

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That one you will have to go into in more detail to make me see Lightarrow? I'm not saying that HUP is the reason for them existing btw, I'm just finding it a 'best explanation' for how they might exist, and exist they seem to do, even if we just have 'indirect evidence' for them:)
But then again, if they're outside observable time, how would we observe them?

Then again, I do have another view of how it might work, but that one is so outlandish that I'll wait with it :)
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Offline lightarrow

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That one you will have to go into in more detail to make me see Lightarrow? I'm not saying that HUP is the reason for them existing btw, I'm just finding it a 'best explanation' for how they might exist, and exist they seem to do, even if we just have 'indirect evidence' for them:)
Yes, but that 'indirect evidence' comes from a *specific* way of computing things: perturbation theory, which is only a tool in making approximate computations in QFT, because we still don'y know how to make the complete non-approximate computations; it could come out that virtual particles are not needed at all if we were able to make the complete computation; infact QFT actually  treats quantized *fields*, not particles; it's that quantization what we usually call "particles".

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Offline Vern

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I found this wiki article that expands on QFT and is in agreement with lightarrow's comments. The last sentence in the quote below gives the reason a virtual particle can never be detected.
Quote from: below
cannot be detected while carrying the force, because such detection will imply that the force is not being carried.

From Wiki

Quote from: the link
In quantum field theory (QFT) the forces between particles are mediated by other particles. For instance, the electromagnetic force between two electrons is caused by an exchange of photons. But quantum field theory applies to all fundamental forces. Intermediate vector bosons mediate the weak force, gluons mediate the strong force, and gravitons mediate the gravitational force. These force-carrying particles are virtual particles and, by definition, cannot be detected while carrying the force, because such detection will imply that the force is not being carried.
« Last Edit: 02/04/2009 13:14:03 by Vern »

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Offline yor_on

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That one you will have to go into in more detail to make me see Lightarrow? I'm not saying that HUP is the reason for them existing btw, I'm just finding it a 'best explanation' for how they might exist, and exist they seem to do, even if we just have 'indirect evidence' for them:)
Yes, but that 'indirect evidence' comes from a *specific* way of computing things: perturbation theory, which is only a tool in making approximate computations in QFT, because we still don'y know how to make the complete non-approximate computations; it could come out that virtual particles are not needed at all if we were able to make the complete computation; infact QFT actually  treats quantized *fields*, not particles; it's that quantization what we usually call "particles".

What I'm having problems with is 'renormalization' :)
And that idea I've had problem since I first saw it Lightarrow:)
And now you say I will have problems with perturbation theory as well
And quantum field theory too??

Lightarrow, do you remember how dissatisfied I am with my understanding of distance:) If distance is something relating, and only relating, to 'frames' observing 'frames', what is uniform motion, speed, velocity, acceleration? And what the heck is a 'direction'?
And perhaps most importantly, what is time?

We seem to describe things from a format where we expect numbers to come up the same, but our universe seems more likely to conform to a 'sliding standard', where things don't come up the same. Like the way time seems to act in QM as compared to our macroscopic universe. When we 'renormalizes' something we expect it to behave in a accountable manner with a clear 'causality chain' showing from the least to the biggest. Now, isn't that a preconception?
 
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Offline lightarrow

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That one you will have to go into in more detail to make me see Lightarrow? I'm not saying that HUP is the reason for them existing btw, I'm just finding it a 'best explanation' for how they might exist, and exist they seem to do, even if we just have 'indirect evidence' for them:)
Yes, but that 'indirect evidence' comes from a *specific* way of computing things: perturbation theory, which is only a tool in making approximate computations in QFT, because we still don'y know how to make the complete non-approximate computations; it could come out that virtual particles are not needed at all if we were able to make the complete computation; infact QFT actually  treats quantized *fields*, not particles; it's that quantization what we usually call "particles".

What I'm having problems with is 'renormalization' :)
And that idea I've had problem since I first saw it Lightarrow:)
And now you say I will have problems with perturbation theory as well
And quantum field theory too??

Lightarrow, do you remember how dissatisfied I am with my understanding of distance:) If distance is something relating, and only relating, to 'frames' observing 'frames', what is uniform motion, speed, velocity, acceleration? And what the heck is a 'direction'?
And perhaps most importantly, what is time?
Now you know a little more why the main breakthroughs in physics happens when we understand the basic concepts better [:)].

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We seem to describe things from a format where we expect numbers to come up the same, but our universe seems more likely to conform to a 'sliding standard', where things don't come up the same.
As to say that one thing is our theory about the world, and another is how the world actually is...

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Like the way time seems to act in QM as compared to our macroscopic universe. When we 'renormalizes' something we expect it to behave in a accountable manner with a clear 'causality chain' showing from the least to the biggest. Now, isn't that a preconception?
Everything, always, is a preconception; nothing more than our mind's creation.
Among these mental creations, the one we call "physics" is the one which works better, that's all.

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Offline yor_on

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So what do you see as 'virtual particles' Lightarrow? That is what we expect to regulate interactions at a atomic level, isn't it? So is there another idea describing them?


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Offline wmmarioblogs

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Thanks, Vern. I guessed it would look contracted but I wasn't sure.

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Offline lightarrow

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So what do you see as 'virtual particles' Lightarrow? That is what we expect to regulate interactions at a atomic level, isn't it? So is there another idea describing them?
In quantum mechanics is difficult to 'see' anything; things become bizarre and far from ordinary experience, physics and mathematics are so linked together that you don't understand where one finish and the other begins...
What we know, or, better, the *description* we have in this moment about microscopic world is that we have fields and these fields have quantized energy. If elementary  particles really exist (and not only the virtual ones) or are merely a useful way to compute things, it's not clear at all, at least to me. Have you ever asked yourself what an electron is? How big it is, how it is done?

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Offline yor_on

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Oh yes, lightarrow.
And if they really are 'there' too:)

If one see time as shape filling up all of 'spacetime' moving from a 'before' towards a 'future', and you then see what we measure as being motion as instead being 'static prickings' made in 'spacetime',  then we would have 'events' again :)

But the 'events' described here would not be represented of any 'sliced time slots' with 'frames' of no-time between them, instead they would consist of 'frozen static events' that 'times arrow' would create the 'motion' for, even though not really existing. And as time then would be a 'flow' we would have a 'arrow of time' constantly 'moving' creating what we call 'motion and distance'. And then those 'virtual particles' would just be a 'matter' of duration of 'pricking' and the real interest for me would be the transitions we see and try to describe, as f ex Planck length and HUP. Outlandish, isn't it :)
 
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Offline yor_on

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Vern, quantum gravity theories (QGT) with gravitons? Shouldn't that be String theory, not QFT, in the manner that it is a theory relating to the standard model it is postulated as an idea I know, But it's still just a theory. The Standard Model doesn't, yet, include any quantum gravity, so it is not a replacement for general relativity.

As I understands it only "string theory includes a massless helicity-2 particle whose behaviour is governed by GR in the classical limit. In this sense string theory - whether or not it's correct - is our only known QGT."
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Offline Vern

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Hi yor_on; I'm having a little trouble understanding your comment. Quantum Gravity Theory would be a quantum theory. There is a string theory of gravity but I think it is different. The article I referenced was about Quantum Field Theory. QFT uses the famous Feynman diagrams to explain the force exchanges between particles.

I looked back through my posts and didn't find where I might have mixed them up; but it is possible I might have [:)]

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Offline yor_on

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If you go by the predictions/expectations made from Standard Model you are correct I think. But we haven't found any gravitons and the ..QFT.. works without that it seems. String theory on the other hand seems to build on the concept of gravitons as I understands it?

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But then again:) I don't really understand string theory, it's a very esoteric subject to me.
Sorry, wrong syllables up there, QFT, not standard Model I meant.
(Time to go to sleep here I think, tomorrow I will give you a better answer Vern, hopefully so:)
Or? awh, been a very long day this one, sorry about that.
« Last Edit: 05/04/2009 23:02:34 by yor_on »
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Offline Vern

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If by esoteric you mean:
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A type of hidden knowledge that is generally known only by a few individuals and not by the general public.
I think that would definitely fit string theory. I never liked string theory because I didn't see the need for it. [:)] I think Lorentz had nature pretty well nailed down back at the turn of the century. QFT, without virtual particles, would predict relativity phenomena, because without virtual particles, forces are restricted to mediation at the speed of light. This would force the Lorentz distortions we see.

 
« Last Edit: 05/04/2009 23:34:28 by Vern »

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Offline yor_on

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Vern you wrote "QFT, without virtual particles, would predict relativity phenomena, because without virtual particles, forces are restricted to mediation at the speed of light. This would force the Lorentz distortions we see."

Could you give me some simple example of how you think here, like A and B moving and...?
Sounds intriguing to me :)
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Offline Vern

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Okay; yor_on; here's the notion:

Set the scene to flat space-time and relativity phenomena in accord with Lorentz.

Lets imagine an atom composed of things moving in a jumble of patterns. If you like we can call these quarks and gluons and electrons. The patterns relate to each other by exchanging gluons which must move at the invariant speed of light. Now, when the atom moves, the gluons must travel a greater distance to mediate the forces. This greater amount of distance requires a greater time, and the pattern must squeeze itself together in the direction of motion, in order to remain intact.

I imagine the patterns to be in accord with my speculative Square-Of-The-Shells rule. But the nature of the patterns doesn't matter, they can just as easily be the QM quark-gluon construct.

QM theory avoids predicting relativity phenomena by allowing the concept of virtual particles; since they are not confined to the natural laws they can mediate forces instantly.
« Last Edit: 08/04/2009 22:30:41 by Vern »

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Offline yor_on

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Ok Vern, I see your idea:)
Let's say that a Atom has a velocity (speed and direction) in spacetime.

If I imagine it like a 3D sphere traveling then it seems to me that the gluons movements should be equalised as they may have one 'length' moving with the 'velocity' and a equivalently shorter length if moving 'back' (depending on if it's in a uniform motion or accelerating, naturally)

So your idea can be seen as a 'deformation' of their lengths, am I right?
But how do you explain how stationary Atoms, relative Atoms traveling, also will become shorter in length, as observed from those Atoms traveling. They shouldn't be, should they? Or is it something I'm missing?

It's a interesting idea Vern.

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« Last Edit: 09/04/2009 01:33:52 by yor_on »
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Offline Vern

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Quote from: yor_on
If I imagine it like a 3D sphere traveling then it seems to me that the gluons movements should be equalised as they may have one 'length' moving with the 'velocity' and a equivalently shorter length if moving 'back' (depending on if it's in a uniform motion or accelerating, naturally)
It is easier to visualize the effect if you imagine the patterns as circles flat-wise to the direction of motion. There you can easily see that the spiral is a greater distance when the pattern is moving. It is not as easy to see but you get the same effect when the circle is moving edge-wise and any angle in between.

Quote from: yor_on
So your idea can be seen as a 'deformation' of their lengths, am I right?
But how do you explain how stationary Atoms, relative Atoms traveling, also will become shorter in length, as observed from those Atoms traveling. They shouldn't be, should they? Or is it something I'm missing?
The atoms travelling will experience a slowing of time because a greater amount of time is required for their patterns to repeat. This will cause them to measure a lesser amount of time required to traverse a stationary object. So they would measure the stationary object as contracted in the direction of their motion.

We can't compare lengths of measuring sticks directly because we would need to bring them side by side. We can only bring them side by side when they are in the same frame of reference.
« Last Edit: 09/04/2009 13:20:00 by Vern »

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Offline Mr. Scientist

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Lorentz contraction has been mentioned a few time in threads just lately. I understand that an oblect travelling at very high speed will contract along its length in the direction of travel.

Now, GR states that if 2 objects pass each other with nothing to reference against, it is impossible for a person on 1 of them to know whether it is the object he is on or the other 1 that is moving.

So, my question is, if I was in a spaceship travelling at relativistic speed and we passed a stationary object, would it appear to me as being contracted? Surely it must to fit in with GR. But if it is velocity that causes Lorentz contraction then it wouldn't affect a stationary ship, would it?

No, it doesn't, nice thought though. No, you see, everything is relative, meaning that the effects of the Lorentz Contraction is not noticed from an inertial frame-reference, but the stationary observer will only observe the contraction. The contracion itself should not effect the observing system in any way, unless we are talking about some extreme examples, such as a relativitic-speed electron passing by a stationary atom and exhanging a gravitional fluctuation we call the graviton. In this case, then the contraction of the moving body and acceleration taking into account has caused a ''curvature'' and emits gravitional effects on another rest atom very close by, millimeters apart, for instance. But i did say it was extreme.
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Offline amrit

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Lorentz contraction has been mentioned a few time in threads just lately. I understand that an oblect travelling at very high speed will contract along its length in the direction of travel.

Now, GR states that if 2 objects pass each other with nothing to reference against, it is impossible for a person on 1 of them to know whether it is the object he is on or the other 1 that is moving.

So, my question is, if I was in a spaceship travelling at relativistic speed and we passed a stationary object, would it appear to me as being contracted? Surely it must to fit in with GR. But if it is velocity that causes Lorentz contraction then it wouldn't affect a stationary ship, would it?

LOrenz contraction was never observed, it is only a math idea
only time shrink, means clocks go slower in fast ship or stronger gravity
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Offline lightarrow

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LOrenz contraction was never observed, it is only a math idea
No, it's not a math idea, it's a physics fact.

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Offline yor_on

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LOrenz contraction was never observed, it is only a math idea
only time shrink, means clocks go slower in fast ship or stronger gravity

Muons then?
This one first.
http://en.wikibooks.org/wiki/This_quantum_world/Appendix/Relativity/Lorentz_contraction_time_dilation
And then take a look at 'Relativistic Length Contraction' here.
http://faraday.physics.utoronto.ca/PVB/Harrison/SpecRel/Flash/LengthContract.html
« Last Edit: 18/04/2009 00:10:18 by yor_on »
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