Does Reciprocity Falsify Special Relativity?

And your point is?

As you and I both already mentioned the constant-velocity propagation is a property of waves in general (including sound waves). What is wrong with my opinion that the principle is more clear and relevant with EM waves than with sound waves? If you dispute the opinion and think that it is more clear with sound waves that is fine, it is just my opinion and you are certainly entitiled to yours. If you think I am making some fundamental error here then be specific.

-Dale

 

Log in or Sign up to hide all adverts.

DaleSpam,

Mass is measured by two of its properties: the ability to attract other mass (react with gravitational fields), and the tendency to resist any change in its speed or direction. Photons pass both of these tests. Their paths curve when the pass by large masses, and they produce a force both when they are emitted, and when they get absorbed and reflected by an object.

Of course, a relativists will say that photons aren't attracted by the gravitational fields of stars, their paths just curve because the spacetime around stars is curved. They will also say that they don't have inertial mass, but instead have momentum. If that's the case, I can say that about any object.

Would anyone like to buy a massless rock from me? When I drop it, it accelerates towards the Earth not because it has gravitational mass, but because it's following the curved spacetime caused by the Earth. And when it hits my big toe and causes severe pain, the force on my big toe is not the result of the rock's inertial mass, but its momentum.

Please Register or Log in to view the hidden image!

I don't believe in time dilation.

 

Log in or Sign up to hide all adverts.

Log in or Sign up to hide all adverts.

You can say it, but you'd be talking nonsense.

 

Now you are just repeating yourself. I don't feel like repeating myself so I refer you to my comments above.

Mass is a well-defined concept in SR, the frame-invarant norm of the four-momentum. So you can "say that about any object" if you wish, but SR certainly does not. The norm of the four-momentum (mass) of a photon is zero to the accuracy of present experiments, the same is not true of all objects.

The force is the result of the rock's change in momentum (dp/dt). The same in SR as in classical physics. Mass doesn't even have the same units.

That's certainly your perogative.

Nature apparently believes in time dilation.

-Dale

 

DaleSpam,

I thought my post was clear. I guess it wasn't. Please tell me how YOU measure mass. And then you can tell me why the same measurements you use to determine that an electron has mass, excludes photons. And don't tell me "Relativity says photons don't have mass" or "mass can't travel at c 'cause Relativity says so". I'm looking for physical proof that can be measured, not far-fetched assumptions and theories.

Why do you believe that? Where's your proof?

 

I have already told you three or four times how I calculate mass. I calculate it as the norm of a particle's four-momentum. The four-momentum can be measured easily in particle colliders. The procedure is no different in principle for an electron, a photon, or a rock, no particle is "excluded". Whenever you measure the mass of any electron traveling at any speed you get 510 keV/c². Whenever you measure the mass of any proton traveling at any speed you get 940 MeV/c². Whenever you measure the mass of any photon of any wavelength you get 0 eV/c².

Protons are often accelerated up to 980 GeV in the Fermi Lab's Tevatron. That's more than 1000x the amount of energy needed to accelerate them to c if relativity were wrong, and yet they don't exceed c. Electrons are often accelerated even faster with more than 100000x the amount of energy needed to accelerate to c in classical physics, and yet they don't exceed c either. Mass can't travel at c 'cause Reality says so.

Synchotrons, GPS, and high-powered cyclotrons and linear accelerators all work and all depend critically on time dilation.

What is the point of this whole photon-mass discussion? You already retreated to some sort of "particle glop" theory of particle creation where particles are born at their four-momentum conserving velocity but their "substance" accelerated before it became "independent of the parent". So a photon still never needs to travel at other than c even if it actually had mass.

You have been unable to convincingly argue that particles accelerate to their "post-natal" velocity and you have similarly been unable to show that if they did accelerate there would be any problem for SR.

-Dale

 

No because physicists chose to say so inspite of the fact that it is merely an assumption based on relativity and in complete disregard that the accelerating forces on these particles you mentioned is by an EM field which is traveling at c.

This is not to say mass can exceed c but only that you nor relativity have proven that it cannot or doesnot.

 

MacM, I am well aware of the fact that you can't "prove" a negative experimentally. Nevertheless he asked for experimental evidence and I gave rock-solid experimental evidence that is in perfect agreement with the theory.

If you have one shred of evidence that mass can accelerate to c then go get your Nobel prize.

-Dale

 

I never said anything about proving a negative.

I said you have not proven v = c is a limit. Such velocities have only been approached using EM fields which themselves move at c. It would be impressive indeed if they COULD cause mass to exceed the velocity of the driving force now wouldn't it.

This has nothing to do with nobel prizes it has to do with retaining just a smigin of common sense.

 

Do you have a citation for this assertion? Have you considered particles which decay into two or more new particles which depart at high speed from each other?

 

Irrelevant. The discussion was about energy vs velocity. Care to show the decay energy applied to velocity of the daughter particles? Can you show where such particles require 10,000 times the Newtonian energy ? :bugeye:

 

Sure you did, even if you didn't realize it. You decided to join in on my discussion with Prosoothus in exactly the spot where he was asking me to prove a negative experimentally. Here's a recap:

SR: "not c"
Prosoothus: "prove it experimentally"
Dale: "particle accelerator energies"
MacM: "but no 'push' faster than c"

A negative can never be proven experimentally for exactly this reason. For any experiment "A" (particle accelerators) where I get a result of "not X" (v not >= c) you can always find some experiment "B" (push with hypothetical tachyons) that was not performed and which might give a result "X" (v >= c). The fact that you know this and have pointed it out at the correct time represents your most impressive accomplishment of this entire thread. You shouldn't try to hide it.

-Dale

 

Lets not try to confuse the issue shall we. My point was that you have never had mass accelerted to v = > c because the method of accelertion has always been an EM field which travels at 'c'.

As I said I am not advocating here (although I believe it true) that mass can move at v = > c but only that emperical data is not proof that it cannot.

 

Sure it's relevant. Do you expect people to believe something to be true just because you say it?

Care to do your own homework? Are you capable of looking something up for yourself?

Look up some decay reactions, and do a search (I doubt Google is enough. You'll probably need to visit a good University library) on experiments with those reactions in accelerators.

 

Sounds very much like a fishing expedition to me. Better luck next time.

 

What issue? We agree. Empirical data can never prove a negative as I showed and as you obviously are aware.

If you have a problem with that then take it up with Prosoothus, not me. He is the one that demanded experimental proof of a negative. I did the best that is logically possible for any theory: I presented solid experimental evidence where a negative result was obtained in agreement with the theory when a positive result was predicted by alternative theories. Nothing better is possible for any theory in experimentally validating a negative.

-Dale

 

DaleSpam,

How exactly do you measure the mass of a moving electron, proton, or photon? By its gravitational interactions? If so, then a photon has mass because it reacts to gravity. Or do you measure it by the force of its impact on another object. If so, then a photon has mass again because it pushes against an object that it impacts (ever heard of a light sail?).

I guess it all comes down to semantics. My definition of mass is any object that possesses both a gravitational mass and an inertial mass. Your definition of mass is any object that contains both a gravitational mass, an inertial mass, and cannot be accelerated to c. You seem to have excluded a number of particles from having mass simply because they don't fit Einstein's theory. I guess it's just another example of how some scientists try to change reality to fit a theory instead of the other way around.

How do you tell if a moving clock is ticking slower because time slowed down or because the speed of the reactions in the clock slowed down? Could it be that the speed of reactions slow down, but time stays constant, for any object that is moving through a gravitational field? If so, why do you disregard this possiblity? Oh wait, let me guess : Cause Relativity says so.

 

That's right, it comes down to semantics.

When you say "mass", you're talking about real physical quantities.

When Dale says "mass", he's also talking about real physical quantities.

The words don't change reality of course... there's no right or wrong in the words we use as far as reality goes.

But, there is right or wrong in the words we use as far as effective communication goes. I respectfully suggest that for effective communication, you'd be better off calling things by the same terms that experts in the field use.

 

Do you think I am going to say something different simply because you have repeated yourself a certain number of times? I have already answered every question and addressed every point here at least twice.

By the way, I think it is highly amusing that you reject SR and yet want to use the concept of relativistic mass as the definition of mass.

That is not my definition of mass, and you know it since I posted it multiple times above. Are you suffering amnesia or just stuttering?

By the way, I also think it is amusing that you talk about trying to change reality to fit a theory given the accuracy with which modern physics predicts reality both for experimental outcomes and for designing working technology.

This actually is an interesting question. I will pose it back to you. If time did not slow down, but only clocks, then how would you know it? Do you have some magic spidey-sense that lets you detect the passage of pure time without reference to some clock?

Now, if a clock slows down then, since the clock is based on some physical mechanism then that physical mechanism must have slowed down. Maybe it is not time, but whatever it is it shows up wherever a physicist would put a t or a d/dt. It fills the same role in the moving frame as time does in my frame. So why not call it time?

-Dale