Why can't we go faster than light?

[Spyman]

But you can have two masses moving with different velocities relative each others and the observer, which frame will be the preferred one, the one where object A has the minimum mass or where object B has its minimum?

 

Inside a Universe with multiple objects moving with individual speeds and each of them have their own "very special" FOR that differs from the others, then none of them can be said to be a preferred frame of reference.

 

In theoretical physics, a preferred or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.

http://en.wikipedia.org/wiki/Preferred_frame

Edited April 1, 2014 by Spyman

[Strange]

When you have a minimum value in graph, doesn't that point differ from all other values?

 

There is a "preferred" mass; the rest or proper mass. But there is not a single frame of reference where this is measured.

 

You are making a leap from "proper mass" to special or preferred frame of reference. That is a complete non sequitur.

[pzkpfw]

When you have a minimum value in graph, doesn't that point differ from all other values?

 

I would agree if there was a way for some observer to measure a mass less than the rest mass. A situation where rest mass of a random object can be measured by some observer in a range going from zero to infinite.

It is not the case.

What we observe is a range going from rest mass to infinite.

So IMHO rest mass is a very special value and the FOR in which you measure rest mass a very special FOR.

 

Any clock at rest with respect to you, will seem to measure the time the same as any other clock at rest with you.

 

Any clock moving relative to you (whether it flies past you on a rocket, or you and your clocks fly past it on a rocket) will seem to be going slow.

 

That gives your own clocks a "special frame" according to your logic; just "maximum" instead of "minimum". Given that's built-in to relativity, what's it going to prove?

 

 

That is, any measurement you make in your own frame is going to be "special" in its own way. But what makes that "preferred" in the "relativity sense", and what are you trying to show by it?

Edited April 1, 2014 by pzkpfw

[michel123456]

 

Any clock at rest with respect to you, will seem to measure the time the same as any other clock at rest with you.

 

Any clock moving relative to you (whether it flies past you on a rocket, or you and your clocks fly past it on a rocket) will seem to be going slow.

 

That gives your own clocks a "special frame" according to your logic; just "maximum" instead of "minimum". Given that's built-in to relativity, what's it going to prove?

 

 

That is, any measurement you make in your own frame is going to be "special" in its own way. But what makes that "preferred" in the "relativity sense", and what are you trying to show by it?

I understand that the laws of physics do not change and that all observers in all FOR must agree on the laws of physics.

I understand that the difference between the measurements made by all observers in all FOR can be transformed from one FOR to another through Relativity.

 

But

 

IMHO there is a very special case that happens when the observer and the observed object are in the same FOR.

To me, it is a preffered FOR because it differs from all the others.

 

Now

 

In theoretical physics, a preferred or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.

 

If I understand correctly, I have to prove that it is simpler to measure my own mass (or the mass of the Earth) than the mass of a flying airplane or the mass of Jupiter.

Does that correspond to the definition?

[ACG52]

 

If I understand correctly, I have to prove that it is simpler to measure my own mass (or the mass of the Earth) than the mass of a flying airplane or the mass of Jupiter.

Does that correspond to the definition?

No, it doesn't.

[michel123456]

 

There is a "preferred" mass; the rest or proper mass. But there is not a single frame of reference where this is measured.

 

You are making a leap from "proper mass" to special or preferred frame of reference. That is a complete non sequitur.

I guess so.

Other FOR will measure my own mass as different. Simply, because observers in other FOR know the Theory, they will not call this mass "Mass" but otherwise.

It would be a non sequitur if you could show me a FOR where my own mass is measured null (for example).

No, it doesn't.

I expected that.

What should I do then?

[Strange]

IMHO there is a very special case that happens when the observer and the observed object are in the same FOR.

To me, it is a preffered FOR because it differs from all the others.

 

You may mean something different by "preferred frame of reference" - this normally means that there is just ONE such frame (which, for example, defines an absolute reference for velocity, etc).

 

However, by your definition, there are an infinite number of preferred frames of reference. Therefore, none of them are preferred. Therefore there is no preferred frame. QED

[I-try]

Both GR and the Newtonian theories have their correct sphere of influence. Regarding a rocket travelling past and close to Earth; Satellite Navigation requires a portion of both; GR with regards to timing of signals received and transmitted. Newtonian for the remainder.

Am I incorrect in believing that for well established practical reasons, NASA preferred to regard the Pioneer Space Probes as remaining in our own special reference frame irrespective of their velocity and relatively increasing distance from Earth. In the same manner, they would have taking into their considerations, the orbit positions and directional motion of the Earth. The Newtonian instantaneous changing of distance would have been taken into account relative to slight changing of radio and laser frequencies; We call that the Doppler effect.

[Spyman]

What should I do then?

You have to show that one observer is in a frame of reference in which the laws of physics are identifiably different than for other observers.

[ajb]

The rest frame of an object is not a frame preferred by nature, but it could be a convenient frame for physicists to use for a specific problem. Because of the rest frame the mass has the nice interpretation as the "rest mass".

[I-try]

Hello to you ajb and I mainly agree with your posts. However, I believe you may have meant to imply that “The rest frame of an object is not a frame exclusively preferred by nature”, but it could be a convenient frame for physicists to use for a specific problem. Because in the local rest frame of an observer, the mass has the nice interpretation as the "rest mass". If I am miss-understanding the meaning contained in your post, could you please supply a clarifying statement.

 

I have suggested the inclusion of the word exclusively, because all rest frames excepting for small distances and volumes, are only an approximation of the parameters acting to provide the total reality relevant to that particular reference frame. The above mentioned parameters extant at all distances and in relatively small volumes included in any preferred rest frame are seldom exactly the same. It is well known that Newton found it necessary to invent Calculus to provide an understanding of instantaneous changing of time, distances and directions relative to acceleration due to gravity or angular momentum.

[ajb]

If I am miss-understanding the meaning contained in your post, could you please supply a clarifying statement.

I am thinking of inertial frames only here, so I won't worry about the local condition in what I said. But if we include GR here then we only have local inertial frames, that is correct.

 

In general relativity and special relativity we are free to use any frame we want. Mathematically this is a choice of coordinate system. In special relativity we have no preferred frame, but rather a class of perfected frames, the inertial ones. All (non-gravitational) physics looks the same in any inertial frame. In general relativity we have a stronger statement that there is not even a class of preferred frames. All coordinate systems are equally as good and the physics is the same in all frames.

 

Now, it is often the case that although there are no preferred frames, there maybe classes of frames that are well suited to the physics at hand. For example, one would normally like to exploit the symmetries that the space-time may have to simplify the description. This also comes in useful when trying to interpret the calculations as out intuition is largely based on flat thinking!

 

So nature may not pick a coordinate system but we for sure can and we can make smart choices.

[SamBridge]

I guess so.

Other FOR will measure my own mass as different. Simply, because observers in other FOR know the Theory, they will not call this mass "Mass" but otherwise.

It would be a non sequitur if you could show me a FOR where my own mass is measured null (for example).

I expected that.

What should I do then?

Just look at the Kelvin scale vs the Celcius scale. Or, let's just make up a new scale. In fact, go stand on a gram scale and then set it to zero. It will read you have zero mass. But, all that means is that when you start moving, some other frame will have to account for that motion by adding in the missing mass later which they find via the equations that correspond constant laws of physics and then they can simply say the scale was offset by a value equal to your mass. No matter what, if your moving in a way that corresponds to having mass, it doesn't matter where you start mathematically, all the inertial frames are still going to agree that you at least have mass in whatever unit they decide to measure it in that corresponds to the laws of physics.

Edited April 3, 2014 by SamBridge

[swansont]

"Preferred" has a special meaning, as Spyman has discussed. If you want to discuss some other aspect, then you need to use another word. Yes, calculations are easier in certain frames, such as the rest frame or the center of momentum frame. That we are free to do calculations in a frame of our choosing means there is no preferred frame.

 

This Minute Physics video seems relatively timely to the discussion.

 

[Schneibster]

In keeping with my standard technique, I offer this answer to the thread title for your consideration:

 

Because it's physically impossible to rotate that far in a time dimension that has a hyperbolic relation to 3-space.

[davidivad]

the speed of light is the rate at which all mass-less particles move. if you interact with the higgs field, then the result is sub-luminal trvelocity. that is why it is a constant and not just a velocity.

Edited April 4, 2014 by davidivad

[I-try]

The rest frame of an object is not a frame preferred by nature, but it could be a convenient frame for physicists to use for a specific problem. Because of the rest frame the mass has the nice interpretation as the "rest mass".

Thanks ajb for your extended reply regarding your number 35 post. I now have a better understanding of your intended meaning.

I also believe, as I understand you do, that the rest mass of an electron would be better referred to as the invariant mass to remove concern engendered by the use of the word rest with regards the identification of the mass being referred to. There is more than enough confusion with regards to concepts referring to the fundamental nature of mass. Reference to relativistic mass is an example of now increasing doubt regarding its physical reality and I stated my reason for doubt on page one of this thread. The reason referred to is if the mass of a matter particle accelerated close to C was to undergo the relativistic mass increase required by GR, and thereby requiring rapid exponentially increasing amounts of energy to achieve a slight acceleration in the direction of motion, the other physical realities demanded by the Newtonian and GR theories regarding the concept mass, require an equal amount of energy to be expended to achieve equal acceleration in any other direction relative to the particles previous direction of motion. Unless I am wrong in my belies regarding the energy requirements to constantly increase the velocity of matter particles in our large accelerator, and implying both changes to direction and increasing speed by the use of the word velocity, then the greater magnitude of energy is expended to achieve increases in approaching speed relative to the opposite direction of motion of the other test matter particles.

Edited April 4, 2014 by I-try

[Schneibster]

the speed of light is the rate at which all mass-less particles move. if you interact with the higgs field, then the result is sub-luminal trvelocity. that is why it is a constant and not just a velocity.

 

Elegant.

[ajb]

I also believe, as I understand you do, that the rest mass of an electron would be better referred to as the invariant mass to remove concern engendered by the use of the word rest with regards the identification of the mass being referred to. There is more than enough confusion with regards to concepts referring to the fundamental nature of mass.

Right, so just call it the mass. For a given particle the mass in a fundamental property and does not change when we employ different inertial frames.

 

The reason referred to is if the mass of a matter particle accelerated close to C was to undergo the relativistic mass increase required by GR, and thereby requiring rapid exponentially increasing amounts of energy to achieve a slight acceleration in the direction of motion...

For a physical particle we have the mass-shell condition which is really the relativistic equation of motion.

 

[math]\sqrt{E^{2}- p^{2}} = m^{2}[/math],

 

in units for which the speed of light is 1. Here p is the three-momentum, which is up to a factor of gamma, the standard momentum.

 

Anyway for a physical particle this condition must hold remembering the term on the right hand side is a constant. You can think of the mass as a constant of motion in relativistic mechanics.

Edited April 5, 2014 by ajb

[SamBridge]

the speed of light is the rate at which all mass-less particles move. if you interact with the higgs field, then the result is sub-luminal trvelocity. that is why it is a constant and not just a velocity.

The faster you go, the greater the coupling rate with higgs particles and thus the greater local curvature and thus the greater the measured effect of time dilation of length contraction that keeps the speed of light the limit. But, why do higg's particles couple more with accelerating objects in the first place, and why does that limit still occur at the speed of light? Why doesn't applying force at a linear rate cause higg's coupling at a linear rate? Or why not at 400,000,000 meters per second instead of 300,000,000 per second?

Edited April 5, 2014 by SamBridge

[davidivad]

The faster you go, the greater the coupling rate with higgs particles and thus the greater local curvature and thus the greater the measured effect of time dilation of length contraction that keeps the speed of light the limit. But, why do higg's particles couple more with accelerating objects in the first place, and why does that limit still occur at the speed of light? Why doesn't applying force at a linear rate cause higg's coupling at a linear rate? Or why not at 400,000,000 meters per second instead of 300,000,000 per second?

 

interaction with the higgs particle is not what creates mass. this is a very common view misconceived i think by the media. the higgs particle proves the existence of the higgs field. it is a disturbance of this field.

 

as far as your question as to why it is a certain speed, i would say that it is the speed of movement. for instance, when we boil things down to the bottom of our measurement ability we realize that particles are essentially results of measurement and of a many body system (the interaction of waves gives the effect of the things we see). i now compare the vacuum of space to water. even an ultrasonic sound travels at the speed of sound in water. in my perspective, velocity itself resides upon the backdrop and is dependent upon interaction itself which in it's simplest form is c.

without any further tail chasing i am simply saying that c is a constant.

i sincerely hope that made sense. if not fire away.

Edited April 5, 2014 by davidivad

[SamBridge]

 

interaction with the higgs particle is not what creates mass. this is a very common view misconceived i think by the media. the higgs particle proves the existence of the higgs field. it is a disturbance of this field.

 

as far as your question as to why it is a certain speed, i would say that it is the speed of movement. for instance, when we boil things down to the bottom of our measurement ability we realize that particles are essentially results of measurement and of a many body system (the interaction of waves gives the effect of the things we see). i now compare the vacuum of space to water. even an ultrasonic sound travels at the speed of sound in water. in my perspective, velocity itself resides upon the backdrop and is dependent upon interaction itself which in it's simplest form is c.

without any further tail chasing i am simply saying that c is a constant.

i sincerely hope that made sense. if not fire away.

So if coupling with the field doesn't cause mass, what about it does? You have quantized portions of the field, higgs bosons, and together they are all apart of a higgs field, and the interaction or the coupling within the field in excited states or "disturbances" via higgs particles and its the interaction that creates mass, or in other words higgs particles are mediators for the coupling with the higgs feild that causes mass. I don't remember seeing that on Nova, so what's missing?

You're later description doesn't make sense me either. Measurement systems can very, but they will still all agree the speed of light is a constant, no matter what that constant is. But, what is making it a specific constant for a given measurement system. We have curvature of space and we have higgs fields, and now you're saying its just some trick of measurement?

Edited April 5, 2014 by SamBridge

[davidivad]

you misunderstood me. i should have been more clear.

the coupling of the higgs field DOES relate to mass.

this has nothing to do with the higgs particle.

the higgs particle is an excitation of this field. it looks like a sombrero hat according to Wikipedia (sorry, i don't normally fall back on wiki just pressed for time).

the importance of the higgs particle is that it proves that the higgs field exists.

 

let me try to explain the second part better.

the speed of light is the speed at which disturbances such as waves move period. it is a constant. everything in the universe can be expressed as a wave function.

interaction with fields such as the higgs field creates a gradient between two fields. if light is a constant then you can create a graph to plot the effects of relativity.

the effects naturally come out as a consequence of comparison.

[Schneibster]

Basically that's Quantum Field Theory's point of view/interpretation of reality, right, davidivad? Second quantization leading to the field that is the probability function for all particles to interact with it at any given point?

Edited April 5, 2014 by Schneibster

[davidivad]

i like your quote from feynman.

 

you are right, i have firm roots in quantum field theory. you can feel the weight of a quantum field theory book in your hand, but can't technically prove a thing.

you just have to accept it.

Edited April 5, 2014 by davidivad