Unbelievable velocity mass variation!

[Grumpy]

OnlyMe

I an beginning to sound like a broken record lately on this issue, but the "E" in E = mc^2 only represents the total energy associated with an object's rest mass (aka invariant mass, inertial mass and gravitational mass). It does not represent the total energy of an object in motion. Any kinetic energy associated with acceleration or velocity has no affect on an object's mass...

Sorry, you are simply wrong. The E=MC^2 is the equivalence between mass and energy, it can be solved in either direction. Mass(of whatever kind)is equivalent to energy if multiplied by the square of lightspeed, energy(of any kind)divided by the square of lightspeed is equivalent to mass. Be it kenetic energy or radiation, energy is mass in a different form and vice versa.

Particles travelling near lightspeed increase mass the closer they get to lightspeed, reread what I pointed out about particle accelerators. Ask yourself why physicists specify "rest mass", don't you think that is a redundancy? It would be if velocity didn't add mass, but it does because kenetic energy has mass of it's own. Again, Dark Energy is 70% of the mass of the Universe.

When an object is moving its momentum and total energy do increase, but neither of these increase the invariant mass, of the particle or object. The whole Lorentz factor issue where relativistic velocities are involved, describes an object's velocity or acceleration dependent inertia, not its invariant inertial mass. (I know that sounds a little confusing.)

Not confusing, wrong. Or unnecessarily convoluted. Mass is mass, rest mass is what a particle weighs at rest, it is not what it weighs at relativistic velocities, thus the necessity of specifying rest mass. The kenetic energy is intrinsic to the particle as is the mass it represents, otherwise why the need of the distinction "rest mass"? No object with any rest mass whatsoever can accelerate to lightspeed BECAUSE it's mass increases, as does the energy required to accelerate it further. Very close to lightspeed this energy increases toward infinity, as does the mass. Dump as much energy into accelerating that mass as you like, the particle will gain more mass requiring even more energy to continue accelerating. Why are gamma rays the most energetic radiation known? Because they are protons or atomic nuclei accelerated to near lightspeed by the most energetic processes in the Universe and even those processes can not accelerate those particles to lightspeed, their mass stops them accelerating further even with the stupendous energy available from supernovas, Black Holes and Quasars.

Grumpy

 

[martillo]

You know I initially had a similar belief as you and that was the aim of creating this thread but I have realized that the concept of velocity varying "relativistic mass" was just an artificially created one and not really appropiated nowadays may be because some misinterpretations it could bring.
May be you haven't read post #6 which everybody agreed:

I have found this interesting refutation in other forum:

“ Mass is an invariant. Its not "relativity" that has ever held otherwise. It is an increadibly outdated definition made prior to our improved understanding of relativity in terms of the full tensor modeling of the laws of physics that you are stuck on. With the understanding of relativity that we have now mass in terms of the force law you are missunderstanding is the proportionality constant between four-vector force F and four-vector acceleration A in
F = mA
It does not change with speed which has to be the case in the full tensor equation because the very postulate of relativity is that the laws of physics do not depend on frame. The mistake others have made and you are following is that when you transform the proper time derivatives in the definitions of F and A to the labs coordinate time due to time dilation the expressions you end up with have factors of γ that you then missassociate with the mass even though they actually had nothing to due with it. They were due to time dilation. So called mass dilation experiments that you are referring to are not actually confirming mass dilation, but are actually confirming time dilation and the tensor law. ”

I must review some things...

Anyway I think the proposed experiment is very interesting...

 

[OnlyMe]

Grumpy, you are auguring an outdated understanding of mass and relativistic velocities. It is perpetuated in popular publications (for $), the internat (which has no moderators to insure information is up to date and correct) and even in some remaining and out dated text books.

I would be surprised if you could find any physicist currently working in a related field that would agree with you.

Try your question and assumptions on PhysicsForums where the moderators jealously and rightfully protect the context for achedemic consumption. I follow threads there but do not often post, as I am a bit on the edge for their standards.

P.S. I like the added freedom this site allows.

 

[origin]

I know that my knowledge in Relativity is very limited but I'm sure one thing, Relativity is a fantastic but wrong theory.

I think this quote is such a peach I had to post it. For me this says all you need to know about martillo and his ideas.

 

[martillo]

“ Originally Posted by martillo
I know that my knowledge in Relativity is very limited but I'm sure one thing, Relativity is a fantastic but wrong theory. ”

I think this quote is such a peach I had to post it. For me this says all you need to know about martillo and his ideas.

This sounds like something to evade what I'm really asking here what is for a specific experimental test on Relativity Theory with a proposed very feasible experiment.
May be you don't want to make it...

 

[Grumpy]

OnlyMe

Grumpy, you are auguring an outdated understanding of mass and relativistic velocities. It is perpetuated in popular publications (for $), the internat (which has no moderators to insure information is up to date and correct) and even in some remaining and out dated text books.

There is nothing "outdated" about it. Modern physicists prove what I am saying every day at CERN. The incredible additional power required to get slightly faster speeds out of hadron, electron or proton beams is well documented, and energy itself has mass as shown by Dark Energy. You may be confused by the detail that modern physics uses to describe the effect, but at base I am correct, else why the continued use of the term "rest mass" when you are saying that that mass never changes?

martillo

May be you haven't read post #6 which everybody agreed

Maybe you are laboring under the delusion that science is a popularity contest. I don't doubt you will find others to agree with you here, but they are all wrong to say particles do not gain mass with relativistic speed, that matter and energy are not two sides of the same coin or that energy itself does not have mass. There have also been threads here denying length contraction at relativistic speed...

"However, thanks to relativity, physicists have some hints of what a proton should theoretically look like when its velocity approaches the speed of light. Due to Lorentz contraction, the proton should contract into a disk with no thickness, or in other words, a two-dimensional disk. This shape is due completely to relativity, and has nothing to do with the interactions between quarks, gluons, etc., which are instead described by quantum chromodynamics."

http://www.physorg.com/news/2011-12-physicists-ultrahigh-energy-proton-black-disk.html

...they were wrong, too.

Grumpy

 

[martillo]

grumpy, or everybody is deluded or you are "old fashioned".
I ask to you: why not to perform the experiment? May be it could bring some light about because, you know, I actually believe the Lorentz factor 1/root(1-v2/c2) actually belongs to the Electric and Magnetic Fields and not to "relativistic mass" nor to "time dilation" nor "space-time curvature" as you like.

 

[Grumpy]

martillo

I actually believe the Lorentz factor 1/root(1-v2/c2) actually belongs to the Electric and Magnetic Fields and not to "relativistic mass" nor to "time dilation" nor "space-time curvature" as you like.

Believe whatever non-sense you like, I'll stick with knowledge and reason. Relitivistic mass gain exists, whether you believe it or not(and seperating it into different components as origin seems to be saying doesn't do away with the effect, it just redefines it).. Time dilation is established fact, your GPS system provides evidence of that hundreds of thousands of times per hour, and if you think spacetime curvature is not real, your arguing with nearly 100 years of physicists that say otherwise(and have provided evidence supporting it). Sorry, you just aren't the physicist you are impersonating, your "beliefs" are as scientific as the Pope's, they are based on beliefs too.

Grumpy

 

[OnlyMe]

OnlyMe



There is nothing "outdated" about it. Modern physicists prove what I am saying every day at CERN. The incredible additional power required to get slightly faster speeds out of hadron, electron or proton beams is well documented, and energy itself has mass as shown by Dark Energy. You may be confused by the detail that modern physics uses to describe the effect, but at base I am correct, else why the continued use of the term "rest mass" when you are saying that that mass never changes?

I don't want to begin a debate. This issue has been covered several times, in a number of other threads.

As for Dark Energy....? It is a place holder, to explain the unexplained.

And as to using the term rest mass, sometimes shown as $$m_0$$, the terms rest mass and invariant mass are mostly only used when discussing this issue. There are times when $$m_i$$ and $$m_g$$ are used to denote inertial mass and gravitational mass, for purposes of function and clarity, but they are both known to be the a same, — or equivalent. I refer you to the principal of equivalence "of inertial and gravitational mass".

Most of the time unless this is the issue being discussed it is just $$m$$ - - mass!

 

[Grumpy]

OnlyMe

As for Dark Energy....? It is a place holder, to explain the unexplained.

The term "Dark Energy" only holds a place in our understanding of the CAUSE of a very real effect(much like Dark Matter does, we know it is there by it's effects, but we don't know what it is). When the Universe was young it was dominated by gravity and the expansion slowed, as it aged and density dropped it stopped slowing and it is today accelerating, dominated by an unknown force we call DE. These are real effects and represent an amount of energy whose mass is equal to 70% of the observed mass of the entire Universe. These are observed facts, dismissing them is not reasonable. Again, energy has mass, it is equivalent to mass and vice versa. Every day our sun converts billions of tons of mass into energy, and after the Big Bang pure energy produced matter. Energy and mass are two forms of the same thing.

And particles(or any other forms of mass)gain mass as it nears lightspeed(actually it gains mass if it creeps across a floor at an inch per hour, it is just that it is inconsequentially small). Whether you seperate that mass gain from the rest mass or not, it still gains mass with velocity(you say inertial mass, I say the mass of it's intrinsic kenetic energy, it's still mass gain with velocity and it is still the effect that prevents acceleration to lightspeed).

Grumpy

 

[OnlyMe]

OnlyMe

The term "Dark Energy" only holds a place in our understanding of the CAUSE of a very real effect(much like Dark Matter does, we know it is there by it's effects, but we don't know what it is). When the Universe was young it was dominated by gravity and the expansion slowed, as it aged and density dropped it stopped slowing and it is today accelerating, dominated by an unknown force we call DE. These are real effects and represent an amount of energy whose mass is equal to 70% of the observed mass of the entire Universe. These are observed facts, dismissing them is not reasonable. Again, energy has mass, it is equivalent to mass and vice versa. Every day our sun converts billions of tons of mass into energy, and after the Big Bang pure energy produced matter. Energy and mass are two forms of the same thing.

And particles(or any other forms of mass)gain mass as it nears lightspeed(actually it gains mass if it creeps across a floor at an inch per hour, it is just that it is inconsequentially small). Whether you seperate that mass gain from the rest mass or not, it still gains mass with velocity(you say inertial mass, I say the mass of it's intrinsic kenetic energy, it's still mass gain with velocity and it is still the effect that prevents acceleration to lightspeed).

Grumpy

What we know is the we observe aspects of the universe that as we interpret them suggest that the universe is expanding at an excellerating rate. We don't know what is causing this and we set a place holder for the cause and call it dark energy.

We also know that as we observe galaxies we find that our best theory of gravity GR fails to adequately describe what we observe, so we asign a place holder called dark matter to make GR work for these otherwise unexplainable observations. But we do not know that there IS any dark matter out there. We don not know that there is not some other yet unexplained interaction that is taking place.

All we know is that as we INTERPRET some of our observations of the universe around us, our best theories do not make sense unless we add an unknown mass and energy to the equations.

Both dark matter and dark energy do not even rise to the level of theory, the are at best hypotheticals at present. Too, often these are spoken of as if they had already been canned and sold at the corner store. They are unknowns that make the best out of what we have to work with at present.

The whole mass issue is old news. I think I can dig up a link to a paper that is not too technical that addresses that issue pretty well, if I can find it I will add it by edit.

Edit: Try reading through this paper, The Concept of Mass, Lev Okun does a pretty good job of explaining the relativistic mass issue and its history.

 

[martillo]

Sorry, you just aren't the physicist you are impersonating, your "beliefs" are as scientific as the Pope's, they are based on beliefs too.

I came up with a pretty new idea and I'm asking to test it scientifically with a proposed feasible experiment. You are stubbornly insisting with the old concept of "relativistic mass" which is not holded in current science. I think you are much more near in being some "Pope" than me.

By the way, I don't understand why there's no mention anywhere of an attempt to try the Davisson-Germer experiment at higher velocities to check the relativistic effects and if there were problems why not to talk about them...

 

[przyk]

I'm asking to make the experiment at some higher velocities to account for the "relativistic" Lorentz factor 1/root(1-v2/c2) and for a more direct measurement of the velocities with a velocity selector (which is based in crossed elecrtric and magnetic fields to obtain electrons with a given velocity in the experiment) added to the original apparatus.

There isn't really a Lorentz factor in the de Broglie relation. The direct relation is $$\bar{p} \,=\, \hbar \bar{k}$$ where $$\bar{p}$$ is the (relativistic) momentum and $$\bar{k}$$ is the wavevector.

That will really verify the De Broglie formula at some "relativistic" speeds. Why not to do it?

Why not contact an experimental physics group with experience with electron diffraction and ask them? What are you expecting posters here to do? Build the experiment out of Lego? We're not doing the experiment ourselves because we don't have the training or equipment, and we're not pressuring anyone else to do it because we don't believe in your cause that it's that important.

I have reasons to think that unexpected results will be obtained since I think the Lorentz factor actually belong to the Electric and Magnetic Fields and not to the De Broglie formula.

You know that, apart from accelerator tests such as LEP and the LHC, relativistic electrons are used in a variety of places including transmission electron microscopes (where their wavelengths are going to be important) right? I haven't looked into the details but I would be very surprised if the de Broglie relation hasn't been tested in some form or other under relativistic conditions. A Google search for "relativistic electron diffraction" certainly turns up plenty of hits.

 

[przyk]

Sorry, you are simply wrong. The E=MC^2 is the equivalence between mass and energy, it can be solved in either direction. Mass(of whatever kind)is equivalent to energy if multiplied by the square of lightspeed, energy(of any kind)divided by the square of lightspeed is equivalent to mass. Be it kenetic energy or radiation, energy is mass in a different form and vice versa.

This isn't really correct. Mass is a form of energy in relativistic physics, in the sense that it contributes to the total energy conservation law. The statement doesn't make much sense the other way around.

Particles travelling near lightspeed increase mass the closer they get to lightspeed, reread what I pointed out about particle accelerators. Ask yourself why physicists specify "rest mass", don't you think that is a redundancy?

Why do you think we have the phrase "relativistic mass"? Everyone here who's been telling you that "mass" generally means "rest mass" nowadays in physics is perfectly correct: that is the way we usually use the term. This is also the reason you'll usually see physicists give the full relation for energy as $$E^{2} \,=\, p^{2}c^{2} \,+\, m^{2}c^{4}$$ rather than $$E \,=\, mc^{2}$$.

Introductions to relativity often use the concept of relativistic mass because it allows for some simple explanations (eg. "particles can't go faster than light because their relativistic mass increases as they go faster"), and the convention used to be more common (see eg. Feynman's lectures, which date from the 1960s), but experienced physicists - especially theoretical physicists - nowadays don't find relativistic mass so useful. Once you've learned four-vector notation you never use it: in relativistic relations such as $$p^{\mu} \,=\, mv^{\mu}$$ or $$f^{\mu} \,=\, ma^{\mu}$$, it's the rest mass that appears every time.

Modern physicists prove what I am saying every day at CERN.

Experiments generally confirm relativistic kinematics and dynamics. They don't show that "mass increases with velocity" or "mass" = "relativistic mass". That's really a matter of convention.

 

[martillo]

There isn't really a Lorentz factor in the de Broglie relation.

How can you say that? De Broglie relation is lambda=h/p where at relativistic velocities p=gamma.m.v and gamma=1/root(1-v2/c2) is the Lorentz factor.

You know that, apart from accelerator tests such as LEP and the LHC, relativistic electrons are used in a variety of places including transmission electron microscopes (where their wavelengths are going to be important) right? I haven't looked into the details but I would be very surprised if the de Broglie relation hasn't been tested in some form or other under relativistic conditions. A Google search for "relativistic electron diffraction" certainly turns up plenty of hits.

The De Broglie relation with its relativistic terms is used to interpret the results for example to derive lattice lengths. This does not check or verify the De Broglie relation at relativistic speeds, just use it.
Be surprised because De Broglie relation hasn't been verified at relativistic velocities or nothing has been published about. If it were this would be treated specifically somewhere in the web and it isn't.

Why not contact an experimental physics group with experience with electron diffraction and ask them? What are you expecting posters here to do? Build the experiment out of Lego? We're not doing the experiment ourselves because we don't have the training or equipment, and we're not pressuring anyone else to do it because we don't believe in your cause that it's that important.

My way at this time is to try to find someone interested in the subject in physics forums, what's wrong about this?
May be you don't believe it is an important "cause". I do believe and naturally I'm trying to call the attention on it. You are not interested, fine, I think some other physicists could and should be interested.

 

[przyk]

How can you say that? De Broglie relation is lambda=h/p

Precisely. That's why I said the Lorentz factor doesn't appear directly in the de Broglie relation.

where at relativistic velocities p=gamma.m.v and gamma=1/root(1-v2/c2) is the Lorentz factor.

This equation isn't fundamental in quantum physics and is only true in a certain sense on average and with some restrictions.

In quantum physics, the de Broglie relation $$\bar{p} = \hbar \bar{k}$$ is actually pretty much the definition of momentum - i.e. apart from the factor of $$\hbar$$, momentum is the Fourier conjugate variable to position. The real feature of relativistic quantum physics is the relation $$E^{2} \,=\, p^{2} c^{2} \,+\, m^{2} c^{4}$$ between energy, momentum, and mass, which defines the dynamics. The relativistic relation between (group) velocity and momentum follows logically from this:

$$
v_{\mathrm{g}} \,=\, \frac{\partial \omega}{\partial k} \,=\, \frac{\partial E}{\partial p} \,=\, \frac{p c}{\sqrt{p^{2} \,+\, m^{2} c^{2}}} \,.$$​

If the momentum distribution is narrow enough you can invert this to get

$$
p \,\approx\, \frac{m v_{\mathrm{g}}}{sqrt{1 \,-\, v_{\mathrm{g}}^{\,2} / c^{2}}} \,.
$$​

So from a theoretical perspective your proposal doesn't make much sense. It's really $$E^{2} \,=\, p^{2} c^{2} \,+\, m^{2} c^{4}$$ in general that you want to be investigating.

 

[martillo]

“ Originally Posted by martillo
How can you say that? De Broglie relation is lambda=h/p ”

Precisely. That's why I said the Lorentz factor doesn't appear directly in the de Broglie relation.


“ where at relativistic velocities p=gamma.m.v and gamma=1/root(1-v2/c2) is the Lorentz factor. ”

This equation isn't fundamental in quantum physics and is only true in a certain sense on average and with some restrictions.

In quantum physics, the de Broglie relation is actually pretty much the definition of momentum - i.e. apart from the factor of , momentum is the Fourier conjugate variable to position.

Well, seems we are exactly in the knot between Relativity Theory and Quantum Physics...
If we would explore the relativistic effects on Quantum Physics surelly we must explore how the Lorentz's factor 1/root(1-v2/c2) appears directly or indirectly in the De Broglie relation.
Very interesting subject isn't it?
And very interesting and important would be to perform the proposed experiment because what if, just for the case, the relation that would actually work "in practice" does not include the Lorentz's factor and this factor actually belongs for instance to the Electric and Magnetic Fields?
I think is something very very important that deserves much more attention.
At the end the real "nexus" between Relativity and Quantum Physics could be unveiled and isn't this what many ones are looking for? I mean how to "match" Relativity and Quantum Physics?
Although, you know, I think that "nexus" actually resides in that both theories are wrong but this is another subject.
The experiment must be performed!
No one interested here?

 

[OnlyMe]

pryzk and martillo,

I am having some difficulty understanding the point of the original question and a few of what appears to be associated issues.

It seems that martillo has been asking for an experiment where the de Broglie wavelength of an electron (seems to me it could be any subatomic particle) is measured and confirmed to be consistent with theory at relativistic velocities. Do I have that much right?

The second question, is from my limited offsite exploration, and I do mean limited. The de Broglie wavelength of any particle with mass varies with its momentum, or velocity since its mass is constant, both the particle's kinetic and at rest energy contributing to the calculations. Is this also, though obviously over simplified, at least a simplistic description of things?

Thirdly, as the momentum of a particle with mass increases, its de Broglie wavelength decreases and it frequency increases. Is this also at least generally accurate?

For my purposes understanding this much is likely best before I delve any deeper into the issue and its implications.

 

[martillo]

I am having some difficulty understanding the point of the original question and a few of what appears to be associated issues.

It seems that martillo has been asking for an experiment where the de Broglie wavelength of an electron (seems to me it could be any subatomic particle) is measured and confirmed to be consistent with theory at relativistic velocities. Do I have that much right?

Right.

The second question, is from my limited offsite exploration, and I do mean limited. The de Broglie wavelength of any particle with mass varies with its momentum, or velocity since its mass is constant, both the particle's kinetic and at rest energy contributing to the calculations. Is this also, though obviously over simplified, at least a simplistic description of things?

The point here is that at relativistic velocities accordingly to Relativity Theory the momentum is P=gamma.m.v with the Lorentz's factor gamma=1/root(1-v2/c2) present and which introduces the relativistic effect in the De Broglie formula.
przyk said on this: "This equation isn't fundamental in quantum physics and is only true in a certain sense on average and with some restrictions." So the question that arises, in agreement with the purpose of the proposed experiment, is if in relativistic conditions the De Broglie relation actually must include the Lorentz's factor or not. Relativity Theory says yes and following przyk this could be questionable in Quantum Physics (note that this would introduce a too important difference with Relativity). What I claim is that the proposed experiment solves this point with testable results which would be very important in Physics.

Thirdly, as the momentum of a particle with mass increases, its de Broglie wavelength decreases and it frequency increases. Is this also at least generally accurate?

Well here a problem appears. With the classical De Broglie wavelength formula an unreachable lower limit for an electron would be lambda=h/mc because it actually can never reach the c velocity but if the relativistic Lorentz's factor is included in the formula (accordingly to Relativity) then lambda=h/(gamma.m.v) and this gamma approaches to zero while v approaches to c so now the variation of the De Broglie wavelength is different and even approaches to infinite while v approaches to c.

So you see it is very important to verify experimentally the De Broglie relation at relativistic speeds. I mean to run the old Davisson-Germer experiment but at some higher velocities enough to detect the relativistic effect (in the original experiment the velocities were about 0.2% of c accelerated by just about 50 volts: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/davger2.html#c1). I proposed a modification to the original apparatus adding a velocity selector to directly determine the velocities of the electrons and not derive them from the voltage measured in the accelerator's plates. I think there would be problems with this.

 

[martillo]

przyk:
I remember have discussed hard but good with you, long time ago (2007), about the invariance of the De Broglie law in the change of relativistic frames of reference and you made me realize that the De Broglie law is invariant in agreement with Relativity Theory. This made me take out of my manuscript an argument I thought I had against Relativity Theory. The thread was: http://www.sciforums.com/showthread.php?t=65661 (The link to my page doesn't work now).
We also discussed the modified relativistic twins problem but here I didn't agree with you.
What I think is important now from your presentation of the invariant De Broglie law is that you included the relativistic Lorentz's factor in the formula and it was just because of this that the relation is invariant under a change of relativistic frames of reference. I mean invariant under a Lorentz Transform. The relation would be not invariant without the Lorentz's factor in it.
So Relativity Theory demands the Lorentz's factor in the formula.
Now you bring a formulation that seems come from Quantum Physics and say that the Lorentz's factor is not essential in it.
This seems to me could be a very important inconsistency between the two theories.
This made me remember Michio Kaku saying at tv that the two theories "hate each other"...