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No this is definitely not correct because if it was the masses of things could be different in different places and times. This is clearly not what is observed. The mass of a particle or an object is just a measure of the amount of energy that has been trapped and located by the particle or object.
If you by mass mean the weight perceived, then that only change in a acceleration. there you can find yourself heavier. We have uniform motion and accelerated motion existing. Then we have what is called invariant proper mass, aka the mass of a planet for example. That mass will always be the same in a uniform motion, no matter if you could accelerate Earth relative the Sun, as soon as it stops accelerating your mass will be the same as before the acceleration.
If the Universe is expanding at a significant fraction of the speed of light then we are moving at a significant fraction of the speed of light.
Quote from: MikeS on 26/09/2011 11:35:20If the Universe is expanding at a significant fraction of the speed of light then we are moving at a significant fraction of the speed of light. Wrong. Every time you say "A is moving" you are making a mistake. You have to say: "A is moving with respect to B".So you see that "movement" is not an intrinsic property of a body, because it always depends on other bodies.Mass, instead, *is* an itrinsic property of a body.
Let's discuss it in form of energy instead. When you accelerate you expend energy, but when you move uniformly you do not. So what exactly gives the added energy in a 'free fall' aka uniform motion/geodesic, as you meet the floor? When it comes to relativistic mass you only gain that in a acceleration, not in a uniform motion as far as I can see. If it was otherwise you would contain a untold number of different 'relativistic mass' on any uniformly moving object of matter, as our Earth. That because all uniform motion are indistinguishable from eachother. It doesn't matter what you measure against, or if you like, it do matter and with each measurement you can define a new 'speed' to our Earth, depending on what you define it against, and so a new 'relativistic mass' if now uniform motion was related to a relativistic mass. Because with a system of two uniformly moving objects in space you are free to define all 'motion' to either one, naming the other as being 'still' according to relativity. In fact I think you would be able to define both as being 'still', instead assuming a expansion of the 'space' in between too? I'm not entirely sure on that one, but I have trouble seeing how you would differ between a expansion and uniform motion there. "Einstein was willing to generalize the equivalence principle, and to conclude that the classical idea of a distinguished class of frames of reference has no physical basis. Any frame that we might regard as inertial might be, for all we can tell by experiment, in free fall. By the same token, any frame that is uniformly accelerating is indistinguishable from one that is at rest in a uniform gravitational field."From ...sorry, you cannot view external links. To see them, please
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You gain relativistic mass by accelerating but you keep it in uniform motion. Relativistic mass increases with velocity.
Ok so lets call all distant points A and our local reference frame B. Isn't this basicaly the same as "If the Universe is expanding at a significant fraction of the speed of light then we are moving at a significant fraction of the speed of light."
Invariant mass is an intrinsic property of a body but I am talking about relativistic mass which isn't.