[yor_on (OP)]

Anyone ever thought about how Einstein defined relative motion?

If you accept that a relative motion is without 'resistance' it shouldn't matter if you from your frame define a binary system 'accelerating' creating a gravitational wave. They don't accelerate, they are following a geodesic 'path' without resistance. Always in a uniform motion as far as I get it? Just like ball thrown up following its geodesic.

[yor_on (OP)]

It seems to me as it as about how you define a 'system', if I'm thinking right, from your frame of reference. Then again :)
It's Friday ::))

[yor_on (OP)]

  What I should add is that Einstein had trouble himself with accepting the idea of gravitational waves.

[yor_on (OP)]

A gravitational wave seems to me to either need a 'bubble' in which it can be said to 'propagate' or you need to redefine a universe to fit.

[yor_on (OP)]

Nobody?

[esquire]

Anyone ever thought about how Einstein defined relative motion?

If you accept that a relative motion is without 'resistance' it shouldn't matter if you from your frame define a binary system 'accelerating' creating a gravitational wave. They don't accelerate, they are following a geodesic 'path' without resistance. Always in a uniform motion as far as I get it? Just like ball thrown up following its geodesic.

the force of the outer expanding universe is without the hinderance of matter; yet, if it's  force has an energy equivalence, it contains a gravity component that provides resistance to the expansion. in this respect, universe is a self contained structure. so we have a self contained structure with a nucleus of matter, expanding at different rates. the universe's matter nucleus, expanding at a lower velocity then the outer expansion of the universe, due to being highly gravity concentric. the relative motion would be primarily the product of their differing values of gravity resistance, measured as drag.

gravitational waves are a compounding of differing gravity values, each object bring a different value of it's gravity to the table. this differentiation of gravity by two colliding object does not produce a single homogenous wave but a stratified wave consisting of two separate values of gravity. this stratified gravitational wave as a structure has an energy/force difference built in. its relative motion is self contained. this self containment is one of force not matter, however, the difference in gravity forces within the wave provides an internal and external mechanism that perpetuates forward locomotion. external and internal complementary gravitational forces/energy that pulls and pushes each other simultaneously. this is similar to the universe's expansion.

relative motion as a mean of forward propulsion.

[yor_on (OP)]

Interesting but not the way I look at it esquire. The universe expands everywhere equally I suspect :) . it's just the 'four forces' keeping us together. And the question is why we define gravitational waves to uniform motions? Einstein thought of those as being as 'straight paths' as possible, no matter how I define a binary star system to dance around itself. If those paths are straight? Does that make gravity a 'force' in the same manner as for example EM?

I don't know, but if you look at repeatable experiments it shouldn't matter what path (or at what speed you define it to have) a uniformly moving body takes, should it? They should give you a same result?

[yor_on (OP)]

Described though energy a body in a uniform motion, to the best of my knowledge, doesn't lose any energy? Not as defined locally any way. Neither does a different speed gain it 'energy' locally measured.
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The first sentence is about it's relative motion, and gravity's possible 'friction' or shear forces or whatever one want to think of it as. The other is about the preconception of 'energy' being stored locally due to a 'relative speed'.

If there are no locally measurable changes, aka ones light bulb suddenly shining stronger or weaker :) due to a changed uniform motion, then there is no gain or loss of 'energy' for a uniformly moving body through SpaceTime as it seems to me. No 'friction' either.

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Well, there is one difference. If you define 'energy' as 'time' then both change interacting in a system. Just as the 'energy' in a collision becomes a product of relative speeds so a time dilation becomes a product of your local clock versus what other clock you measure. But that one can only hold for a system of 'bodies' interacting, and in both cases both your 'energy' and 'local clock' never change locally defined.

[evan_au]

Described though energy a body in a uniform motion, to the best of my knowledge, doesn't lose any energy?

"Uniform motion" implies a flat universe, where a geodesic is a straight line.

However, in our location near the Sun, and within the gravity well of the galaxy, space is not perfectly flat, so our geodesic is not a straight line - it is bent into an orbit around the Sun (and, in longer timescales, around the Galaxy). And it is this tiny deviation from a straight line which produces a tiny amount of gravitational waves.

It is estimated that the Earth/Sun system radiates about 200W of gravitational waves continually, which is miniscule compared to the amount of sunlight striking the Earth, let alone meteors.

Gravitational radiation really only becomes significant in human timescales with compact, massive objects like neutron stars and black holes, in close orbits.

[esquire]

consider that time/space warps. it warps to differ degrees depending on the presence of matter. with less matter available the frontier of space/time is less disturbed.  the expansion of space/time is less encumbered in a field where warps in gravity and electromagnetic forces are not present. its forward locomotion is not impededed by the presence of electromagnetics or by a stronger warping of gravity associated with mass.  this is essentially unimpeded motion. the motion of the mass within the universe flows at a different rate due to the resistance of electromagnetism and the effects of a warping space/time. the relative motion between the two expansions is verifiable. the red shift expansion of the universe demonstrates that objects are moving away from us faster than the SOL. different velocities within the expansion of the universe make this possible. these different velocities embody relative motion. we see a universe moving away from us at an accelerrated rate because we as observers are veiwing the expansion from a slower velocity perspective. in our self contained universe the expansion force in a placid space/time flows at different velocity then the disturbed space/time warp of it matter nucleus.

when two star approach each other, their warped gravity fields comingle to create a gravitional wave upon the collision between the two stars. the separate gravity value with different rotational velocities imbues relative motion to the gravitional wave. the velocity of the rotational differences creates a gravitational structure that is akin to a swirl, two separate values combined into a single formed structure. within this structure the differences from the two distinct gravitional fields remains. this imbues the gravitional wave with a self contained relative motion. this relative motion creates its own force of locomotion with its own capabilty of warping space/time.

thank you for you kind reply, consideration and time.

[yor_on (OP)]

Evan " However, in our location near the Sun, and within the gravity well of the galaxy, space is not perfectly flat, so our geodesic is not a straight line - it is bent into an orbit around the Sun (and, in longer timescales, around the Galaxy). And it is this tiny deviation from a straight line which produces a tiny amount of gravitational waves."

The way I understand it a geodesic is a straight path through SpaceTime Evan. And as I remember that was the way Einstein thought of it too, at least in the beginning. With the introduction of gravitational waves, which wasn't his idea even though you could fit it to his equations, I'm not sure if he changed his idea there?
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It makes for a very different universe if you think of geodesics as 'straight paths'. It questions all 'bubbles theories' there is.

[yor_on (OP)]

And Esquire, you see where we differ in our positions reading my reply to Evan I hope?

[esquire]

sure, uniform motion. the relative motion between entangled or virtual particles! the smallest measurement must be a straight line! how uniform motion and relative motion coincide is a matter of degrees in quantum and/or standard physics.

thinking small and large at the same time. is not  being lost in complexity.

last post in this thread i promise.