Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1873347 times)

Online WarpTech

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Einstein's Equivalence Principle still rocks!  ::)

But...
Stage 2 has gone through the same acceleration and momentum change and should have experience the same subatomic effects as Stage 1. So why would it operate?  In fact after reaching the first delta-v and turning off Stage 1, the two stages should be indistguishable. So why could Stage 2 accelerate and Stage 1 be "dead"?

I didn't say that. They would be indistinguishable. If after reaching delta-v with Stage-1, it is now "hovering" at a constant potential. Turning off Stage-1, it now continues with constant inertia in free-fall. If you turn on Stage-2, identical to Stage-1, it's now hovering again at the same potential. If you turn on both stages, you've doubled the Power so it will accelerate to 2*delta-v.

The difference will be in that when the engine is running, there is an acceleration toward the floor, when it's off, you're floating. The relative speed does not change, and just like pushing on a wall, no work is being done. So although the engine is running, it's is not increasing the inertia any higher. To increase the inertia further, a higher input power is required.

Hmmm.. So t becomes an artificial gravity machine upon reaching delta-v?

More like it's being chased by a black hole, similar (?) to Dr. McCulloch's model. At constant acceleration, the faster you go the closer the black hole gets and eventually the ship reaches a limit to where it can't go any faster because all the power you have can only keep it hovering at this distance from the event horizon. :)

Didn't the Borg project a black hole in front of the cube to create their warp drive?  8)

Todd


Offline phaseshift

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Einstein's Equivalence Principle still rocks!  ::)

But...
Stage 2 has gone through the same acceleration and momentum change and should have experience the same subatomic effects as Stage 1. So why would it operate?  In fact after reaching the first delta-v and turning off Stage 1, the two stages should be indistguishable. So why could Stage 2 accelerate and Stage 1 be "dead"?

I didn't say that. They would be indistinguishable. If after reaching delta-v with Stage-1, it is now "hovering" at a constant potential. Turning off Stage-1, it now continues with constant inertia in free-fall. If you turn on Stage-2, identical to Stage-1, it's now hovering again at the same potential. If you turn on both stages, you've doubled the Power so it will accelerate to 2*delta-v.

The difference will be in that when the engine is running, there is an acceleration toward the floor, when it's off, you're floating. The relative speed does not change, and just like pushing on a wall, no work is being done. So although the engine is running, it's is not increasing the inertia any higher. To increase the inertia further, a higher input power is required.

Hmmm.. So t becomes an artificial gravity machine upon reaching delta-v?

More like it's being chased by a black hole, similar (?) to Dr. McCulloch's model. At constant acceleration, the faster you go the closer the black hole gets and eventually the ship reaches a limit to where it can't go any faster because all the power you have can only keep it hovering at this distance from the event horizon. :)

Didn't the Borg project a black hole in front of the cube to create their warp drive?  8)

Todd

No, they created a transwarp conduit enabling them to go Warp 10 - allowing them to be all places simultaneously and they then could exit the transwarp conduit at a location of their choosing - Suspend disbelief when everything else in the episodes said something else. If you collected all the 'data' from the episodes trying to figure out Borg propulsion technology you would stand zero chance of figuring anything out. LOL The Romulans did power their warp drive with a singularity though :)

Todd, you almost had me with where you were going with things but it is practically the opposite of everything I have learned about GR/SR. I get what you are saying and I've thought the same things years ago and was hammered on that I was absolutely wrong. I'm not a professional physicist so I accepted that I was wrong but I'm going to reexamine all of it and see where I end up.  Having a conceptual cleanroom universe in which to do thought experiments seems to work in most situations - but when there are gravitational and EM fields everywhere it's a different story. :)

« Last Edit: 06/07/2015 01:27 AM by phaseshift »
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Offline Rodal

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If EM drives like to be free to accelerate to thrust, so be it, if they don't like to be accelerated to thrust, so be it, either way, a buffering intermediate link can accommodate for those whims, at a very, very, very modest energetic cost. So, a 40s long thrust of 50N for 50W at constant velocity, that is exactly the same conditions as claimed results at Eagleworks, if it is reproducible many times, can be used intermittently to reach break even velocities, in principle (if not in practice). What could possibly make it, in principle, not reproducible many times if it can genuinely work one time ? Growing distance with the lab, or cumulative disturbance of the Force ?
The 40 second long thrust was not at constant velocity. Roughly speaking there was transient (let's say for discussion sake in the remaining of this post, that it was about 2 sec long) with constant velocity and after 2 sec it was (roughly speaking) zero velocity.

So

40s 2 sec long thrust of 0 to 50N linear rise at constant velocity,
   ~40s long thrust of 50N for 50W at zero velocity


During the 2 second rise, what you see is the damped harmonic oscillator response to a step force

It is not the response of an EM Drive free in space, of course.  What would that be?  We have no idea.  If the EM Drive is an artifact, it won't do anything in space.  If it isn't we have to choose a theory to model it (Shawyer, McCulloch, Notsosureofit, etc.)

What was measured at Eagleworks looks like a Force step response



Going from my memory now, I recall that what is being measured is the displacement, and that the displacement looks like a linear rise during the first 2 seconds, and then the displacement is constant for the remaining duration until the power is turned off.

So, we have, approximately, to first order  (Ahem, not legally speaking  ;) ):

Displacement = rises linearly from t=0 to t=2 sec, and it stays constant x=x0 after that
x = (xo/2)t  0 < t < 2
x = xo                t> 2

Velocity
v = (xo/2)    0 < t < 2
v = 0                  t>2

Force = k x ,  rises linearly from t=0 to t= 2 sec and it stays constant k=xo after that
F = k  (xo/2)t  0 < t < 2
F = k xo                t>2

ENERGY (Elastic Potential)
EE = (1/2) k  ((xo/2)t)^2     0 < t < 2
EE = (1/2) k (xo)^2                    t>2

WORK
W =  k  ((xo/2)t)^2 = 2 EE    0 < t < 2
W = k (xo)^2 =2 EE                     t>2

KINETIC ENERGY

KE= (1/2) m (xo/2)^2           0 < t < 2
KE = 0                                          t>2

elastic POWER (time rate of Potential Elastic Energy)

PE =  k  (xo/2)^2  t               0 < t < 2
PE  = 0                                        t >2

Velocity and kinetic energy are constant during first 2 sec and then they are zero until power is turned off.
Displacement and force rise linearly during the first 2 sec and then they stay constant until power is turned off.
Elastic power rises linearly during first 2 sec and then it is zero until the end of the test until power is turned off.
Elastic energy and Work rise quadratically with time during first 2 sec and then they stay constant until power is turned off.


Note: the rise  is really an exponentially damped harmonic function, so there is an acceleration as well, but the exponentially damped harmonic response has been linearized here as it looks linear to the eyeball, so this is a simplification to first order.  After the first 2 sec, there are some small amplitude damped oscillations as well

In a damped oscillator, the force feeds energy into the system. The damping force always takes energy out,
because the damping force always points antiparallel to the velocity.

« Last Edit: 06/07/2015 02:09 AM by Rodal »

Offline birchoff

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@WarpTech

So under the assumption that I accept your theory of operation. What experiments would need to be carried out to show that the EmDrive Frustum behaves as predicted. And for those of us who secretly harbor dreams of a much simpler way of getting into orbit, What is the predicted thrust scaling of the theory.

Offline TheTraveller

Inside the EMDrive frustum all it knows of the world outside is when acceleration causes internal Doppler shift, dropping Q and stored energy, which converts into Kinetic. Reverse happens if something tries to move it small end to big end. Acts like a Kinetic energy sink.

Push big end toward small end and it is a Kinetic source, push it the other and it is a Kinetic sink.

That doesn't resolve the energy paradox though.  The EMdrive doesn't have to be accelerating at all to act as a free energy machine, so converting EM energy to kinetic energy when an acceleration occurs solves nothing.  This has been fleshed out a few times now, so I'm just going to link to my previous post on the matter: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1385685#msg1385685.

Free energy doesn't require acceleration, so CoE during acceleration just isn't enough.

If the EMDrive is not acceleration (in motor mode) nor opposing acceleration (in generator mode), some small fraction of cavity energy does turn into thermal energy, assuming constant input, due to wall losses.

How is this a Free Energy Source?

Did you read the post I linked?  It doesn't require a perfectly efficient cavity, where no power is lost to resistive heating effects.  Such power losses can be, and are free to be, quite large.  All that matters for the analysis to hold is that the Thrust to Power ratio is greater than 1/c, which has been true for all EMdrives to date.

As long as the thrust to power ratio is greater than 1/c, there will be a break even velocity where, when held at constant velocity (so no "motor mode" effects), the emdrive creates more power than it takes in.  It doesn't matter if the power it takes in is converted to heat or unicorn dust. 

Please, read the link.  You will see that thermal energy losses in the cavity don't play into this issue at all. 

(note: I reserve the right for the preceding analysis, props to @frobnicat, to potentially be made irrelevant by theories like @warptech's.)

My reply was in regard to your statement that a non accelerating EMDrive was still a source of Free Energy. Could you please resopnd to this quote:

Quote
The EMdrive doesn't have to be accelerating at all to act as a free energy machine,

I'll get to responding to your link shortly, which I'm sure you know Shawyer has already made comment on the severe acceleration limits which apply to a superconducting EMDrive.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline SeeShells

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Quote
Because, when the engine was running, every sub-atomic particle of matter was accelerated and in dong so, their momentum increased. Relative to where it started from, the wavelength of every matter-wave has been reduced in size and this represents the real stored energy of inertia. Therefore, the matter that was accelerated "knows" it was accelerated because it possesses more inertia than when it started. In this regard, when the engine is turned off, it is equivalent to orbiting at a constant gravitational potential (v^2), in free-fall at a constant velocity, as opposed to hovering at this potential when the engine was running.

Einstein's Equivalence Principle still rocks!  ::)

Todd

So let me get this right. The real reference frame isn't the gravitational field but spacetime? Since that is how an object "knows" it's speed from the stored compression of the matter it's made of? So if we backwards think this and look at the Emdrive removing that spacetime compression while it's running...

The real reference frame is the rest frame the mass started from. As work is done to accelerate it, matter acquires inertia which is physically stored as a reduction of the wavelength of matter waves, leading to relativistic length contraction and time dilation as physical effects as v -> c. For v << c, the effect is still there, but we perceive it as inertial mass, or total energy content of the body. The inertial mass of an object moving at velocity v is greater than it was in the frame in which it started.

Again, this is not a Lorentz transformation anymore, this is GR not SR. This is that part of SR that they leave out when trying to explain the Twin Paradox. Then they say "it's because one of the twins was accelerated". You must integrate along the world-line of the matter being accelerated to get the right answer. It's not simply comparing 2 identical inertial frames, it is comparing 2 inertial frames at different gravitational potentials.

Todd
Hmmm. I find this interesting and I'm trying to wrap my brain around it. I thought the Higgs field gave mass to matter and part of the mass it has was as it traveled through the Higgs field.
What your saying makes some sense, but if I have a object traveling at lets say near light speed, it's mass increases we know that, now does that increased mass warp spacetime like a star or a black hole? If it did pass close to lets say me floating in free space would I feel its gravitational effect in passing?

Sorry if I'm being silly here but you have a good way with words.


Offline rfmwguy

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Really a pleasure to read posts on all sides of the em drive...wish I were in the 0.5% club like many here ;)

Since I tend to go macro...I am visualizing fields whose strength is inversely proportional to spacetime...iow...weak forces can span huge distances. Pehaps we are leaving our preoccupation with strong nuclear forces and heading towards the understanding and utilization of the opposite.  As always, thanks for activating some of my dormant brain cells  8)

Online WarpTech

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Again, this is not a Lorentz transformation anymore, this is GR not SR. This is that part of SR that they leave out when trying to explain the Twin Paradox. Then they say "it's because one of the twins was accelerated". You must integrate along the world-line of the matter being accelerated to get the right answer. It's not simply comparing 2 identical inertial frames, it is comparing 2 inertial frames at different gravitational potentials.
Hmmm. I find this interesting and I'm trying to wrap my brain around it. I thought the Higgs field gave mass to matter and part of the mass it has was as it traveled through the Higgs field.
What your saying makes some sense, but if I have a object traveling at lets say near light speed, it's mass increases we know that, now does that increased mass warp spacetime like a star or a black hole? If it did pass close to lets say me floating in free space would I feel its gravitational effect in passing?

Sorry if I'm being silly here but you have a good way with words.

Thanks, no problem.
Yes, and yes. In an accelerated reference frame the total inertia of the mass warps spacetime and makes pushing it faster like going up-hill. The faster it goes, the steeper the grade. At some potential, there is not enough power available to push it to a higher inertia. The best you can do is "hover", and if you turn off the engine you "orbit" meaning free-fall at constant velocity. It shows an accelerated reference frame is identical to a gravitational field, as it should be.

Also, the Higgs field is a scalar field. Newtonian gravity is a simple gradient of a scalar field. Probably the same thing, IMO. I don't know enough about the Higgs field to say more than that. My understanding is, the equilibrium power exchanged between matter and the EM ZPF, works pretty much the same way for all ZPF's, including the weak and strong nuclear force fields, and the Dirac field. So my model of how gravity and inertia work is the same, all the way down to the smallest scales and highest energies. IMO however, I only care that it works. Where it's right or wrong will come out in the end, so far, it works better than any other engineering physics model I've seen.

Todd
« Last Edit: 06/07/2015 02:17 AM by WarpTech »

Offline Notsosureofit

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A little awkward in statement, but the right idea.

Offline SeeShells

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Again, this is not a Lorentz transformation anymore, this is GR not SR. This is that part of SR that they leave out when trying to explain the Twin Paradox. Then they say "it's because one of the twins was accelerated". You must integrate along the world-line of the matter being accelerated to get the right answer. It's not simply comparing 2 identical inertial frames, it is comparing 2 inertial frames at different gravitational potentials.
Hmmm. I find this interesting and I'm trying to wrap my brain around it. I thought the Higgs field gave mass to matter and part of the mass it has was as it traveled through the Higgs field.
What your saying makes some sense, but if I have a object traveling at lets say near light speed, it's mass increases we know that, now does that increased mass warp spacetime like a star or a black hole? If it did pass close to lets say me floating in free space would I feel its gravitational effect in passing?

Sorry if I'm being silly here but you have a good way with words.

Thanks, no problem.
Yes, and yes. In an accelerated reference frame the total inertia of the mass warps spacetime and makes pushing it faster like going up-hill. The faster it goes, the steeper the grade. At some potential, there is not enough power available to push it to a higher inertia. The best you can do is "hover", and if you turn off the engine you "orbit" meaning free-fall at constant velocity. It shows an accelerated reference frame is identical to a gravitational field, as it should be.

Also, the Higgs field is a scalar field. Newtonian gravity is a simple gradient of a scalar field. Probably the same thing, IMO. I don't know enough about the Higgs field to say more than that. My understanding is, the equilibrium power exchanged between matter and the EM ZPF, works pretty much the same way for all ZPF's, including the weak and strong nuclear force fields, and the Dirac field. So my model of how gravity and inertia work is the same, all the way down to the smallest scales and highest energies. IMO however, I only care that it works. Where it's right or wrong will come out in the end, so far, it works better than any other engineering physics model I've seen.

Todd
Now your paper makes more sense and that is where I was struggling in how you saw the Higgs field and now I know you treat both gravity and inertia the same. And you're right we will see how it ends up in the wash.

Thanks bunches, this calls for a glass of something red and maybe a hot tub. ;)
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Online aero

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I've been following this discussion and one thing I wonder about. When you turn the engine off, what happens to the Inertia? Obviously if you are hovering in a gravity field, you fall, but in freespace what happens to it?

I see no reason for the ship to loose it's accumulated momentum but does it? The extra inertia of the engine particles must dissapate when the power is removed?
Retired, working interesting problems

Offline Notsosureofit

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Just passing though, not really up to date, so take w/ pound of salt....

Free Energy:  As I recall (maybe) , any Maxwellian device following a closed curve is subject to a retarding potential known in the trade as "back emf".

"Free Energy" in the remaining circumstance is meaningless from a practical point of view. 

The best GR explanation of closed loops are written about "twin paradoxes", don't have a ref. w/ me, but they are out there.

Hopefully there is some sense in that....

Offline TheTraveller

I've been following this discussion and one thing I wonder about. When you turn the engine off, what happens to the Inertia? Obviously if you are hovering in a gravity field, you fall, but in freespace what happens to it?

I see no reason for the ship to loose it's accumulated momentum but does it? The extra inertia of the engine particles must dissapate when the power is removed?

When a mass is accelerated, it's velocity, in reference to an initial stationary reference frame, continually increases.

When the acceleration stops, the velocity stops increasing and remains constant.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline deltaMass

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I've been following this discussion and one thing I wonder about. When you turn the engine off, what happens to the Inertia? Obviously if you are hovering in a gravity field, you fall, but in freespace what happens to it?

I see no reason for the ship to loose it's accumulated momentum but does it? The extra inertia of the engine particles must dissapate when the power is removed?

When a mass is accelerated, it's velocity, in reference to an initial stationary reference frame, continually increases.

When the acceleration stops, the velocity stops increasing and remains constant.
What you describe is true for any inertial observer frame.

It's also instructive to see how changes in kinetic energy transform between inertial frames. Like this, in 1D:
dE1 = dE0 + V dv
where
V = relative velocity of frames
dv = change in velocity of object

Note: This relation is non-relativistic.
« Last Edit: 06/07/2015 03:59 AM by deltaMass »

Online dustinthewind

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I've been following this discussion and one thing I wonder about. When you turn the engine off, what happens to the Inertia? Obviously if you are hovering in a gravity field, you fall, but in freespace what happens to it?

I see no reason for the ship to loose it's accumulated momentum but does it? The extra inertia of the engine particles must dissapate when the power is removed?

When a mass is accelerated, it's velocity, in reference to an initial stationary reference frame, continually increases.

When the acceleration stops, the velocity stops increasing and remains constant.

One way I came to grips with accelerating inertial frames was I realized what happens in between two frames of special relativity.  For there to be contraction of outside space, then, when when one is accelerating is when the contraction happens.  I was thinking of how relativity seems to enhance classical effects like momentum, mass, and energy and I wondered if us living in an accelerated frame (gravity) means our frame is continuously contracting and relativity enhances this?  That is, space continuously contracting into the earth suggests a flow into the earth.  It sort of made sense that something was dragging us as it flows in. 

In a sense a rocket ship accelerating is similar as it also experiences this dragging (artificial gravity) and it seems that local space wants to travel with the observer (via resistance).  So when the observer stops accelerating then local space seems to have caught up. 

I suppose one could think of the resistance to acceleration as a negative potential or pressure behind the observer and a positive potential in front.  If that potential can be reversed electromagnetically then it might be possible to make space drag us along towards something similar to a gravity well.  One would then instead generate a negative potential in front and a positive potential behind.  Our problem is how to induce that potential.

My attempt at it was to use the time delay of information to make the current in front see the current behind appear to be traveling in the opposite direction and so experience repulsion.  When the information approaches the rear current it appears the top current is in the same direction and it experiences attraction.  One problem with this is that static charge (capacitance) works against this.  However, I am wondering if a TE01 mode for a cylinder experiences that static charge build up thus bypassing the back reaction?  Due to the flow of current it doesn't immediately appear to me to have charge build up and if it is purely magnetic I wonder if it would work. 

It is quite interesting to see all the different theories of how we might accomplish a more efficient form of propulsion.  I am sure it is a long held dream of many and I hope something can be found. 

Online WarpTech

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I've been following this discussion and one thing I wonder about. When you turn the engine off, what happens to the Inertia? Obviously if you are hovering in a gravity field, you fall, but in freespace what happens to it?

I see no reason for the ship to loose it's accumulated momentum but does it? The extra inertia of the engine particles must dissapate when the power is removed?

Nope, the inertia is stored as length contraction and time dilation, i.e, curved space-time, relative to where it started from. I just updated to v3 of the paper, because so many were asking about what happens when the engine is turned off and back on again. It's like pushing against a wall. You can feel the force, but no work is being done because the matter has reached an equilibrium state, for the available power. I deleted the part about the refractive index and replaced it with GR metric coefficients.

See attached revision. Hopefully, this should clear up all the misconceptions about a preferred frame too. I've also cleaned it up a bit thanks to everyone here, for your input and questions. It really helps to solidify what is going on and where more explanation and understanding is required.

Todd



Offline deltaMass

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Equation 2) is making the assumption that there exists a preferred frame. Because for v << c, you are writing
P = F v
and we all know by now what that implies, I would hope. The entirety of the rest of your paper rests on this assumption. Throwing gammas around with abandon does not change this basic fact.
« Last Edit: 06/07/2015 06:04 AM by deltaMass »

Offline Tetrakis

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The real reference frame is the rest frame the mass started from. As work is done to accelerate it, matter acquires inertia which is physically stored as a reduction of the wavelength of matter waves, leading to relativistic length contraction and time dilation as physical effects as v -> c. For v << c, the effect is still there, but we perceive it as inertial mass, or total energy content of the body. The inertial mass of an object moving at velocity v is greater than it was in the frame in which it started.



Not just that, but  "frame-invariant" absolutists are not taking into account that frame-invariance only applies to isotropic constitutive material properties. Frame-invariance does not apply to chiral anisotropy and diverse kinds of anisotropy where there are preferred material frames.  Blindly imposing absolute frame-invariance on the EM Drive is precluding anisotropic explanations based on chirality for example. 



Absolutists? Count me among them. Conservation of energy and the isotropic universe are some of the founding principals of modern science. Sure, anisotropic explanations might be true, but as EMdrive proponents have largely conceded, the operation and design of the EMdrive crucially depends on the violation of one of these principals. Would you refer to >99% of physicists and other scientists dogmatic absolutists? They, and for that matter journal editors, R1 PIs, and governmental program managers in places like the NSF and DOE, aren't going to be convinced that there is a problem with those assumptions unless there is some really serious experimental evidence.

Online WarpTech

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Equation 2) is making the assumption that there exists a preferred frame. Because for v << c, you are writing
P = F v
and we all know by now what that implies, I would hope. The entirety of the rest of your paper rests on this assumption. Throwing gammas around with abandon does not change this basic fact.

In GR there is a gravitational field and it literally has a "scaling" affect on matter. In that regard, the initial rest frame of an object sets the initial scale. Not all rest frames are equal, though none are any more preferred than any other. They are just different, based on the relative inertia content of the object or its relative gravitational field potential.

Again, any ruler or clock we define as a tool is a relative comparison of one thing to another, neither of which has any absolute value or scale. 1 meter is what we define it to be and use this to compare to something else, but 1 meter is not the same on earth as it is on Jupiter, due to gravitational length contraction.

dx = dx'/|sqrt(g_11)|

dx is not the same if g_11 changes. You can say g_11 = 1 is a preferred frame, but it's not. It's simply what it is defined to be, based on the local scale. Scale is not invariant in a gravitational field, and the gravitational field spans the entire universe. Everything is relative to everything else. There is no way to get outside the Universe, at least not without undermining the definition of the word the way string theorists do. ;)

Here's one example. We define 1 meter here on Earth, orbiting Sol, in the Milky way galaxy. With this ruler, we measure light from distant galaxies that was emitted long ago, and the farther back we go with measuring wavelengths, we discover the faster the galaxies are receding away from us. The effect is nearly linear, so we propose the Big Bang Theory. What if, just for giggles, we're wrong. And over the course of billions of years since light left those far-off galaxies, our meter stick has been shrinking by just 6.8 nanometers/century? Well, when we use this ruler on a static universe that is not expanding, we would measure the Hubble constant. Just saying....  ;D

Todd



Offline deltaMass

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Why are you veering off into abstractions about GR? You seem to be obsessed with it. You haven't addressed head-on my simple observation that you have presupposed that energy conservation obtains. In an early post to this thread
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875
I showed that if you assume P = F v,  then conservation automatically follows.

I am using Newton in a field-free flat spacetime at relative velocities severely smaller than c. There is no GR here. There is no SR here. There is classical mechanics and you have just made a postulate that guarantees that conservation obtains. The price you pay is to have selected a preferred frame.

The ghost of Einstein is going to hunt you down.

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