# The Naked Scientists Forum

### Author Topic: How does a 'field' become observer dependent?  (Read 200873 times)

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #450 on: 12/01/2014 20:47:53 »
Although it still makes sense to me, defining inertia as a constant?

There must be a way of making sense of that one.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #451 on: 12/01/2014 20:50:33 »
It must have to do with what mass is, how it can come to exist, if it is going to make sense.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #452 on: 12/01/2014 20:52:14 »
What makes mass able to accelerate?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #453 on: 12/01/2014 21:02:16 »
As you stand on Earth you're being moved in time, the same definition is correct for all motions, none excluded. Assuming it all to come down to local principles etc, I then need to define this earthly gravity relative the proper mass I stand on, now ignoring 'infinite reach' of all mass acting on each other for a while.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #454 on: 12/01/2014 21:08:02 »
What does inertia need?

momentum?
Displacements?
Mass?
=

Does a wave have a momentum? A photon? It has..
So not momentum, unless I want to define a mass to a photon.

Defining a mass to a photon also should define different 'time dilations', depending on energy. I don't like that one at all.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #455 on: 12/01/2014 21:09:18 »
It depends though? If you imagine it as 'propagating', or as 'non propagating'.
=

Assume a very high energy, evenly distributed. Transform it into photons. Now assume that the higher the energy, the greater the mass. That should give you gravitational time dilations and Lorentz contractions, comparing between frames of reference, assuming frames of reference being applicable to such a scenario. That one depends if you trust a photon to be a 'individual', or not.

the speed may be the same, but their energy can differ. And in a Big Bang?
« Last Edit: 12/01/2014 21:52:06 by yor_on »

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #456 on: 12/01/2014 21:13:35 »
Is there some analogue to microscopic displacements possible, considering a proper mass from its particles? You should be able to define gravitational time dilations, and so Lorentz contractions, there too as it seems to me?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #457 on: 12/01/2014 21:18:18 »
That would move it from a constant uniform accelerations displacements being responsible to one in where we would use the definition of the time dilations and Lorentz contractions we find in both descriptions, wouldn't it? Those then being the definition of how a gravity comes to be?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #458 on: 12/01/2014 21:19:27 »
But it doesn't answer how a rest mass comes to be.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #459 on: 12/01/2014 21:27:33 »
You can use energy defining how a particle comes to be, shooting particles through a EM-accelerator, measuring if there is new interactions. But those interactions are short lived, decaying back into 'stable particles' as I get it. So there is a difference.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #460 on: 12/01/2014 21:34:38 »
Using my definition we then find frames of reference, interacting, creating new but short lived rest mass (particles). And the energy of a particle, is that a temperature? It is when it interacts, so what is your definition of a particle? One single frame of reference, 'at rest' in/with itself? Or frames of reference, interacting?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #461 on: 12/01/2014 21:59:12 »
Could you use 'energy' defining it? Nah, don't think so? The energy represented by Earth, relative its gravity, is infinite magnitudes greater than the energy your rocket spend, although it is increasing the closer you get to the speed of light. Thinking that way, where do we find a equivalent amount of energy, as the one represented by Earth? And is that a equivalence? Not to 'gravity' at least :)

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #462 on: 12/01/2014 22:17:54 »
Do you need rest mass to apply 'frames of reference'? That one I think could be translated to 'do waves interact', and they do, they quench and reinforce. But photons then? Don't really know, it depends on your definition I think. Two-photon physics thinks it can. "Two-photon physics, also called gamma–gamma physics, is a branch of particle physics that describes the interactions between two photons. If the energy at the center of mass system of the two photons is large enough, matter can be created."

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #463 on: 12/01/2014 22:32:16 »
If we define mass as 'energy' then everything must interact, the rest becoming a question of transformations and symmetry breaks, due to temperature? And then everything must have a equivalence to mass.

But the energy represented by a rocket at one uniform constant G, including the expenditure do not equal the energy represented by Earth.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #464 on: 12/01/2014 22:37:11 »
Well, maybe not a vacuum. It depends on your definitions, as long as no one can present a experiment proving it, one way or another.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #465 on: 12/01/2014 22:49:42 »
So, can gravity be a measure of energy? Or is it a measure of inertia expressed through time dilations and Lorentz contractions? Displacements inside a arrow? Or something all together different?

To the first question I will say no. Gravity is not a measure of energy, as I can't find a equivalence?
The next one is really tricky, and I just don't see how to answer it.

Displacements in them selves don't answer it either, as I can see.

The third? We have a uniform constant acceleration being equivalent to gravity? And there you can experiment to find it locally true. And that is displacements, and depending on how you think of it also microscopic time dilations and Lorentz contractions. You may be 'at rest' with your particles in a uniform motion, but you're definitely not 'at rest' with them in a acceleration.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #466 on: 12/01/2014 23:17:36 »
Maybe I'm looking at it from the wrong angle? If it is a 'constant', it is a 'constant' related to mass, not to waves or photons. Otherwise someone need to show me how I define a inertia to a photon, or a wave. That makes inertia a function of proper mass versus accelerating displacements. All course changes from a geodesic should then represent a acceleration. But then we have this idea of a photon also being able to represent a 'mass'? Never felt really comfortable with that one, although there is a equivalence between mass and energy.

If a photon is equivalent to a mass, why doesn't it accelerate? you can only measure it in its annihilation, and possibly the 'recoil' of it leaving.

'Energy' being 'mass' then?
I don't know what 'energy' is.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #467 on: 12/01/2014 23:30:14 »
Ok, I'll give you this. You can define a photon acceleration/deceleration as its energy becoming blue respective red shifted. And that one is related to frames of reference, and gravity. But that's not what we normally define as a acceleration. Looked at from frames of reference the blue/redshift is a result of your local frame interacting through relative motion, accelerations and gravity with whatever frame you define that photon to originate from.

Do you want this to be what 'energy' is?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #468 on: 12/01/2014 23:34:48 »
Another way would be to define 'energy' from transformations. What it 'cost', and what it 'lose' doing that transformation. That's the one I like myself.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #469 on: 12/01/2014 23:41:08 »
The isolated definition of a photon is something 'time less', able to pass through all of the time we think this universe to existed. Of a same energy the whole way, annihilating as soon as it interacts, with what ever result from that interaction, then becoming a new photon released as proven by the recoil. You can define it as 'elastic' interactions too, but that only mean that you can't find a difference between what's incoming and outgoing, and it's sort of questionable to me.
=

Maybe you could define a question here?
If a elastic interaction exist, can there be a recoil?

If there is no recoil, did it interact?
« Last Edit: 13/01/2014 03:13:30 by yor_on »

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #470 on: 12/01/2014 23:44:32 »
So the blue and red shift becomes just another description between frames of reference, the observer defining it. Not unlike a time dilation, and just as real for that observer.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #471 on: 12/01/2014 23:55:27 »
Ah well :)

Nothing is as simple as one want huh.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #472 on: 13/01/2014 00:41:03 »
There is the 'mass energy equivalence' in relativity though, defining it as the proportionality between equivalent amounts of energy and mass is equal to the speed of light squared (E=MC2). that enable you to translate a proper mass into a same amount of 'energy'. But, can we apply that one to this? To give the constantly uniformly accelerating rocket a equivalent energy to a whole earth, transformed to 'energy' via E=MC2?

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #473 on: 13/01/2014 00:44:43 »
Nevertheless, the equivalence principle is experimentally correct. Why gravity works this way? Or as I then would want it to be :) A inertia, expressed in time, becoming gravity? Beats me.

#### yor_on

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##### Re: How does a 'field' become observer dependent?
« Reply #474 on: 13/01/2014 00:49:33 »
That I look at it one way doesn't state I have any understanding of why a universe should be one way or another. You just look at the rules of the game, and try to define them so they make sense to you. And the more you learn about those rules, the more traps you will find :) but hey, it's not the game, it's how you play it, right?

Heh.

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##### Re: How does a 'field' become observer dependent?
« Reply #474 on: 13/01/2014 00:49:33 »