# Are there experiments demonstrating relativistic mass-increase?

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#### zordim

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##### Are there experiments demonstrating relativistic mass-increase?
« on: 27/11/2012 17:55:31 »
Does anybody know where I can find the latest and most accurate test results for this effect?
(I was surprised to see that none of the particle accelerator lab web-page does not contain these data)
I did not find anything but the very old "Kaufmann experiment".
« Last Edit: 04/12/2012 22:34:10 by chris »

#### yor_on

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##### Re: Relativistic mass-increase
« Reply #1 on: 29/11/2012 17:44:41 »
« Last Edit: 29/11/2012 17:49:09 by yor_on »
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#### Phractality

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##### Re: Relativistic mass-increase
« Reply #2 on: 29/11/2012 22:07:43 »
What confuses me is the question of whether relativistic speed affects both inertial and gravitational masses equally. Consider a pair of objects in gravitational orbit around one another. They have one orbital period when their barycenter is stationary in the observer's reference frame and a different orbital period when moving near the speed of light in the observer's reference frame. Increased inertial mass slows the orbit in proportion to gamma; increased graviational mass speeds it up by gamma squared; time dilation slows the orbit down by gamma.

This suggests to me that the gravitational attraction between the two objects depends on their speed relative to one another, rather than their speed relative to the observer. Perhaps the gravity of the pair pulls harder on objects that are stationary in the observer's reference frame, but they don't pull harder on each other.
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#### yor_on

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##### Re: Relativistic mass-increase
« Reply #3 on: 30/11/2012 08:36:45 »
Could you break that one down a little for me Phractality?

To me it is strictly observer related, meaning that when you're watching a binary system moving close to lights speed what you see is what you got, as defined by your frame of reference. The relative mass of that binary system is to me observer dependent, and as you say, if at rest with that system, what do you measure?

Are you suggesting that due to different uniform motions (speeds) of a binary system there should be a increased mass expressed, as measured being at rest with the system as well as when not being at rest with it?

So if the solar system was found to increase its speed relative (. . ? .) we also should experience a stronger gravitation due to the solar systems increased relativistic mass? The problem to me with it is that all uniform speeds are dependent on some referent from where you define it, whether you use the CBR or very distant 'fixed' stars. How exactly would you define a speed, relative what? That one is really confusing to me and a question I really would like solved, if it in any way is possible. Relativity don't expect that one to be solvable as I get it, and using that as a fact you get a observer dependent universe in where 'WYSIWYG' as the slogan goes.

What more it implies to me is that there must be a really big difference between what we call 'relative motion' and accelerations. It would be seriously interesting to be able to define a uniform motion as a absolute, observer independent, 'speed' but if one could, how would one explain that gravity won't change locally?
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#### yor_on

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##### Re: Relativistic mass-increase
« Reply #4 on: 30/11/2012 08:47:55 »
From locality's point of view a simple definition is that all uniformly moving systems are 'at rest' locally, and the only 'speeds' one measure is those relative ones own, being at rest, 'unmoving'. But then you have 'energy', and the 'energy' of a system relative another is dependent on the 'speed' you measure it to have, relative yours own naturally (unmoving). And so you can define all sorts of energies to Earth depending on what you measure it against, also depending on whom you define as 'speeding' relative the other.
=

What more may be interesting to note is that the Higgs mechanism don't seem to address this question at all. The only thing it defines is a mechanism by which a acceleration will be notable locally, but it does not address the underlaying question of what a 'speed' really means. All as I get it naturally.
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And when it comes to all things living, be it plants, earth, or animals, it all must be considered 'accelerating processes', as I see it? It's a idealized concept, the idea of geodesics. Relating not to the earth itself as it have all kinds of inherent (intrinsic too?) physical processes going on constantly, all of them able to be considered as 'accelerating'. A geodesic only discuss the way a object follow a path of 'no resistance' and so are uniformly moving but ??
« Last Edit: 30/11/2012 09:06:20 by yor_on »
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#### JP

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##### Re: Relativistic mass-increase
« Reply #5 on: 30/11/2012 17:15:15 »
Since we're dealing with general relativity, what meaning does the relativistic mass have?  In SR it's more physically useful since it describes a lot of the kinematics going on, but when space-time curves, you need to use an energy-momentum tensor to describe kinematics, so I'm not sure relativistic mass tells us nearly as much...

I don't know the answer, but it's food for thought on why it might not be so meaningful when you include gravity.

#### yor_on

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##### Re: Relativistic mass-increase
« Reply #6 on: 01/12/2012 00:17:54 »
I think energy and momentum is a more understandable description although I'm not sure what relativistic mass, or 'energy', is Momentum I'm sort of getting, although I find the concept of 'potential energy' lacking when it comes to uniform motion. In a acceleration you definitely has a added 'energy' locally though, you can feel it acting as a 'gravity/inertia' on your body, but in a uniform motion all local effects of whatever speed you might define are lacking as I understands it, and so the 'energy'. The other way might be to consider a acceleration as gravity solely, not confusing it with a 'energy'? But if we go by the Higgs mechanism it should be considered 'energy', aka Higgs Bosons, if I'm getting it right? As for the stress energy tensor, that one is so difficult to coming at grip with, especially when considering where that 'energy' should be localized, and how? Because, if I assume that there is a 'energy build up' created through different uniform motions, how does it express itself and how would I go about measuring it?
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#### Pmb

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##### Re: Relativistic mass-increase
« Reply #7 on: 02/12/2012 12:05:40 »
Does anybody know where I can find the latest and most accurate test results for this effect?
(I was surprised to see that none of the particle accelerator lab web-page does not contain these data)
I did not find anything but the very old "Kaufmann experiment".
Any experiment done in a particle physics lab proves the relativistic mass relation is quite precise.

#### zordim

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##### Re: Relativistic mass-increase
« Reply #8 on: 03/12/2012 16:25:46 »
Dear Pmb, dear all,
I am especially interested in results which accurately measured mass (or kinetic energy) for velocities $$\geq \frac{3}{4} \cdot c$$, and in matter-antimatter collision experiment results, which measured gamma radiation they produce.
I would be very grateful for links, if you know any.

Zordim

#### Pmb

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##### Re: Relativistic mass-increase
« Reply #9 on: 05/12/2012 02:00:15 »
Since we're dealing with general relativity, what meaning does the relativistic mass have?
Same as you mich excecpt from non-relativistic mechanics.  In SR it's more physically useful since it describes a lot of the kinematics going on, but when space-time curves, you need to use an energy-momentum tensor to describe kinematics, so I'm not sure relativistic mass tells us nearly as much...

Quote
I don't know the answer, but it's food for thought on why it might not be so meaningful when you include gravity.
There's more to it than you might know. Please recall the article I wrote on the subject at http://arxiv.org/abs/0709.0687