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Anything in space hitting you when you are doing .97c will punch a hole straight through your space ship - and the background radiation of the universe will be blue-shifted upto very uncomfortable temperatures.
I'm not sure how you defined this one Phractality. Are you assuming both systems F0 and F1 to be 'still' relative the expansion, in terms of co-moving, relative what? In F0 relative a planet inside the system, but in F1 relative some imaginary points in space, but made how? And how would they differ from using Earth as a coordinate? Either you assume that those points can be defined as unchanging even if considering a expansion, which I don't think is possible globally, as you from any other point must find fond those points positions to 'move' in a expansion?
If a expansion is related to the space around galaxies then you have only the points inside the galaxy to use, if on the other hand a expansion is allowed to exist inside the galaxies, gravity and mass (suns/planets) acting a buoys in the water, anchored relative each other keeping a same distance then no position can hold true? Except relative gravity/mass possibly. And then all positions become 'relative', relative a expanding vacuum.
If I assume all galaxies as being 'unmoving' relative each other, as in uniformly moving galaxies keeping their distance relative each other (Ignoring a 'expansion' that should mean, not their motion relative each other:). Then arbitrarily defining any of them as my 'point of origin' will present me with different time dilations/length contractions, depending on how I define my relation relative that other galaxies 'relative motion'. And as each galaxy can be used as that point of origin, and as we can assume us to measure different 'speeds' relative those other galaxies it all becomes a relative question what length contraction, or time dilation, you might expect measuring. Or maybe I'm missing the point here?
Yeah, I see what you mean, but to be concrete about a time dilation/contraction here you must need to consider what their motion is, relative each other, in any uniform motion, as I think? Consider A and B moving as one, 'at rest' with each other relative A and B meeting/passing each other. Maybe it's me needing to see how comoving is defined? I've thought of that as a 'mathematical device' simplifying the math by excluding the effect of an expansion, but? You still have galaxies moving in opposite directions and even if ignoring a expansion it should matter what velocity they have relative each other.As for the rest i will need to read it carefully Phractality, and hopefully see how you think there tomorrow. It's quite late here now
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When it comes to a expansion I'm not sure what it means in form of 'time dilations & LorentzFitzGerald contractions' actually. The reasonable (most simple) approach to me is to treat this as any other 'motion'. But then we have the question if the expansion is accelerating. If it is then we should notice the 'gravity' changing, to fit relativity. And as far as i know the gravity measured has not changed?So then we have the idea of a expansion being something belonging to 'space' and distinctly different from any ordinary type of 'motion'. If that is correct you can ignore a expansion for this as a guess. The whole idea of 'space' in 'motion' actually makes me head hurt.
Let me see if I get it right Are you thinking of including the expansion in the calculations of where a celestial object should be, not where it appears to be according to the light we measure at each time? And then also consider how much the space would have 'expanded' under the time it took for that celestial object to get where its 'real position' should be? Meaning not the 'apparent one' when judging by the light itself.
When it comes to a 'blueshift'?I don't know at all, if a blue shift is definable from a expansion we need to assume some sort of interaction between a light quanta and 'space'. And if 'light' is a field, then the wave picture is not enough to explain it. Only if assuming that 'waves' is what create a 'field' and the 'excitations' we call 'photons' would it make sense to me. Assuming a 'field' and then thinking that this 'field' creates 'waves'? And then also define those waves as some better approach to the light-duality create a 'preferred frame' to me, and tells me nothing in the same time.
Interesting reading you Phractality I'm thinking that an expansion, if existing, only relate to blue shifts, for now that is. If it does it becomes a statement of a geometry changing, and the geometry change being equal in all directions at each 'point'. Then we will either need to put a layer of 'waves' upon this geometry and describe it from that, or we will need to assume some deeper connection between light and space, aka a field. But a field is not waves, and it's not photons. It's a field, and what makes a field change is the arrow, not interactions per se. Interactions is a second hand effect to the idea of there being a arrow of time to me.
Nikstlitselpmur? Can you prove that light lose energy propagating? If you mean that it is frame related I agree but if you treat a light quanta in situ, then it never lose any energy. Better link up what you state there.
K, that makes sense Although one thing, if you're discussing a time dilation/contraction too you must then specify relative what frame you define it. In this case it would be the CBR as I understand you? When it comes to F1 relative F0 you then should expect a similar blue and red shift for both, generally seen, as both then must relate their dilations etc to the cosmic background radiation. I think you need to go into why you need to define two different SpaceTime coordinates relative how those entities (F1 F0) move a little more for me to get it. If you're assuming that the plasma cooled differently depending on relative motion/acceleration for those measuring I think you are correct, and if using the CBR as the 'preferred frame' defining it you will find each observer to have its own 'time scale', although all of them related through Lorentz transformations. It's tricky in that different uniform motions must bring with it different time dilations etc, relative what is measured locally. And there, as you point out, you also have relativistic blue shift which differs from normal blue shift (ambulance sound). Assuming you can ignore relativistic blue/red shift you can simplify it a little But you need to define relative what you measure the effects as I think.==K. it's been fun Phractality
That's gravity Nik If anyone can prove it otherwise I'm very interested but as far as i know the light disappearing from the far observers frame of reference will, in a thought up 'comoving' frame, or better expressed, 'at rest' with that light propagating, still be there, happily making its way.
Light loses energy due to gravity at its origin,as it travels through space and away from its point of origin, this was predicted by general relativity, and proven by Radek Wojtak of the Niels Bohr Institute. The universe may in fact extend trillions of light years beyond the Hubbles field of view because the light from these distant objects loses most of its energy before it comes close enough to observe. CBR may in fact be the extent of the distance light can travel before it fades away, as objects beyond this limit would still emit radiation which travels farther than light due to the energy imparted at origin, Red shifting light has less energy than blue shifting light, ultraviolet, X-rays, and gamma rays have more energy than radio waves, microwaves, infrared, and visible light, and therefor travel farther.
BTW Nic, if you don't mind, what has your ideas to do with Phractality's? You saw something you thought of as a common nominator or? Was it the question for the thread??
Light from beyond the Hubble limit can never reach us because the distance between us and the source is increase faster than the speed of light. The CMBR that we see comes from stuff that was close to the Hubble limit when the plasma first became transparent.
That's true Nik, you can apply a receding/shrinking point of view towards us existing as matter, instead of defining it as a expansion, as they become mirrors of each other. Distance is a weird subject in relativity too. I've just reread Radeks hypothesis about light relating it to time dilations and I'm not sure what's so different with it compared to Einsteins treatment of it with 'clocks'? They will still only be a consequence of 'frames of reference' meaning always demanding relative comparisons between your local clock/ruler and some other frame? What exactly do you find different with it?