Absolute Velocity - Meaningful but Useless

Here is a definition of absolute velocity that would be meaningful. But also useless. Suppose that, before the Big Bang, or whatever theory you believe in, everything in th universe was at rest, in a particular frame of reference. This frame may be called the absolute frame of reference. MacM, is this what you've been trying to tell us? Although this notion is somewhat meaningful, it is completely useless. For one thing, it is purely circumstantial. It has no place in theory. The existence of Earth is circumstantial, in the same sense. It exists, given that all the other things before it existed. Secondly, even this absolute frame is nothing special. It does not have any special properties. No one can detect it, or a velocity with respect to it, by doing experiments which do not involve <I>everything</I> in this universe. Its only claim at distinction is historical, that is to say, circumstantial.
<Br>
The first postulate of special relativity says that we cannot detect whether we're moving or not without looking outside our frame of reference. This is in no way challenged by the existence of an absolute frame of the above kind.
<Br>
Ether hasn't been detected, and cannot be detected. Perhaps we cannot deny the existence of ether. But we can't detect its existence either, let alone prove it. This means that we can't determine the frame in which <I>ether</I> is at rest, even if it existed.
<Br>
Can anyone offer an intutional argument at least why an absolute frame, with special, detectable properties, should exist?

 

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Absolute velocity cannot be made to coexist with Special Relativity in anyway that is meaningful. In other words, any absolute frame you come up with would be itself an arbitrary relative inertial reference frame.

The only absolute velocity that experiment has ruled out is a universal absolute velocity. It has been put forth by some that along with gravity, massive bodies effectively create a local ether. Therefore trying to measure a massive bodies absolute velocity (i.e. Earth) would come up with a null result as has been seen. Note that this view is not compatible with special relativity and cannot be considered the same thing.

 

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Take another look. I didn't say that it was a non-inertial frame. I've specifically mentioned that this frame is purely circumstantial, and that it doesn't possess any special properties. This is <I>not </I> ruled out by special relativity. I've said that it is not possible to detect it, unless you bring every particle in the universe to a state of relative rest. That is what special relativity says too (its first postulate).

 

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The reference frame that Rosnet discusses actually exists and is detectable - specifically the microwave background. The earth's motion against this background is detectable by doppler shift as a function of direction.

 

Rosnet,

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If the first postulate extends to the entirety of the universe as you suggest, you are going to have one hell of a time arriving at any physical justification for supporting the claims .
I will provide you with three four, five systems cpaable detecting absolte speed, zero velocity poingts what ever. Take a look at what I define as "linear Sagnac systems", and you will begin to get a clue to the gross errors of SRT and the shortsightedness of the limiting imposition on physical law.


Your description of an absolute zero reference frame is grossly misplaced. One only needs to provide a series of points in space that do not move. This simply means that the point defined by some physical activity,these points in space that are physically invariant would be extremely helpful. All velocities, including the speed of light could then be measured from an absolute zero velocity point, or set of points, or in SRT terms as frames of reference that were not only uniform in "motion" but perfectly uniform, to wit, at perfect rest.

Take two expanding photon spheres in space. A straight line connecting the emission points of the spheres would also have a natural and invariant midpoint btween the shortest distance between the closests points on the spheres. The points on the spheres would be closing on each other, yet from the postulates of light that assures us that the speed of light is constant, that light moves in a straight line and is independent of the motion of the source of the light we are provided with a plethora, an infinite number of invariant points.

Astronomical measurememts would be greatly enhanced beyond our wildest imaginations. Adiosw dogma, though, would provide some very sad muic to many who refuse to even consider the possibilities.

Lest there be some ambiguity stirring in some minds the invariance of which I speak means simply: The midpoints do not move in space despite the infinite number of stellar masses moving in virtually all directions in space. These motions then are measurable in speed and distance from an infinite number of invarinat points. Lest we not confine ourselves to the natural invarinat midpoints, artificial, manmade zero velocity points can be produced with trivial ease.

Simply emit two photons (or more, or less) and reflect the emitted light back to the emission point. The outward motion say moving a distance ct is reflected 180 degrees and when moving an additional ct the light returns to the emission point, with zero drift. The point is easily maintained by the continuous motion of the emitted light.

Of course some physical interruption of the moving light is always possible, but when considered in the short term, short distances with rapid repetition of emitted photons, the invariant points are generated at will wityh trivial functrional losses. All motion then is measurable wrt velocity = zero.

Even when the moving light is interrupted, the invariant poiunt is still existent, it is just harder to maintain information of the location of that point. Theoretically, the invariant attributes of the points are impossible to disturb.

If one cannot see a navigation benefit here, as a a minimum of functionality, then one should seriously considered extending the theoretically imposed limitation on modeling physical dynamics in the motion of light and matter.


The statements in this thread and others attempting to link the "universe" to some abvsolute frame of reference is of no value as a matter of expanding awarness of physical law or for the advances in sophisticated technology.
Geistkiesel

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Explain please.

 

I've heard this in passing but have never actually read the report/findings. Can you link to any?

 

I got these from google. With a little exploration, you'll get more.

http://www.astro.ubc.ca/people/scott/cmb_intro.html
(comment in the middle of the article)

http://www.astro.ucla.edu/~wright/CMB-DT.html

 

I don't think so.
THe first postulate says:

The laws of electrodynamics and optics will be valid for all frames in which the laws of mechanics hold good.
Every physical theory should look the same mathematically to every inertial observer.
The laws of physics are independent of location space or time.​

I don't think it's the same thing.

 

CMBR dipole, Astronomy Picture of the day

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This image shows how the background radiation (averaged over a year) is blueshifted in the direction of the constellation Centaurus, indicating that the Solar System is heading in that direction at 600km/s, relative to the "CMBR neutral frame" (a term I just made up).

 

Thanks - I'll have a look.

 

The latest issue of Scientific American has an excellent article on the power modes (dipole, quadrupole, ...) of the CBR (and some interesting anomalies), if you're interested. Very informative.

 

Geistkiesel, don't you see that the points which you say are 'physically invariant', are still relative. They're the midpoint of two other points in every refernce frame. Allright. But that only means that they're invariant with respect to these two points. With respect to any other point, they'd have changed (due to length contraction). According to your argument, every point in the universe is the midpoint of pairs of other points. Then this means that every point is invariant, which they're not, according to observation.

 

Pete, please take a look at the 'Relativity for Sciguy' post. I've explained what is meant by the first postulate there. You'll se that we're in perfect agreement.

http://sciforums.com/showthread.php?t=47363

 

No it isn't. But then neither is the concept of absolutes useless. One day soon you may realize that GPS only functions because it relies upon absolute (relative) velocities and not relative velocity as applied in SRT.

Since James R likes to knit-pick and has said that is a contridiction in terms, let me make clear what an absolute relative velocity is vs relative velocity.

In SRT relative velocity is assumed because you have no other frames of referance and an observer cannot detect or sense his own inertial motion.

Therefore the assumption is that A sees himself at rest and B having all motion, hence all relavistic affects apply to B. Likewise SRT advocates "Reciprocity" where B can equally claim to be at rest and claim that it is A that has all motion and hence all relavistic affects apply to A.

That creates the "A" clock running slower than B and at the same time the B clock running slower than A paradox (actually physically impossibility).

The meaning of absolute relative velocity is that a third observer can see that both A and B have component velocities which comprise their total relative velocity.

They are absolute in the sense that you cannot reverse their status claiming which one has the greatest motion and hence only one will display an affect of relavistic velocity. This is in complete accord with observation and ALL data to date whereas SRT is not.

Absolute in this context is not a universal absolute. It is a comparative absolute to some third frame.

From this perspective it can be seen that to avoid the impossible and unsupported view of reciprocity that we must rely on a common rest frame between moving components.

That is at some unkown point in history two objects may have been at relative rest and have become accelerated so as to have some collective relative velocity.

Not knowing that history one cannot use relative velocity to predict which clock will be dilated, because it is fact that only one can and will be dilated not both.

The assertion by SRT that both are equally dilated would mean we could never record time dilation. The fact that we have proves the failure of that concept.

If two objects initially at rest become accelerated in opposite directions to a collective relative velocity of 0.866c, the affect between such clocks very much depends upon the magnitude that each accelerated from that common point of rest.

i.e. - Equal and opposite: Each would have (using Velocity Addition Formula) a relative velocity of 0.577c with respect to their common rest origin and the fact is neither would display any accumulated time differential or time dilation between them inspite of their relative velocity.

If one did not accelerate, the one that did, would have all absolute relative motion and would tick at only 50% the rate of the one that remained at rest and that fact is not and would not be reversable upon comparison of clocks as predicted by SRT.

Hope this clarifies the issue of absolute. It does not yield some universal absolute value but prohibits reciprocity and varies the amount of time dilation expected due to accumulative relative velocity.

All tests to date (except GPS) have been of the one clock accelerates and hence gamma is verified but reciprocity is falsified by such data.

GPS uses absolute velocity of orbit relative to the common rest frame, the center of the earth (ECI). All GPS calculations are to some third common rest frame.

 

Ha ha! That's funny. Since when did 'Absolute velocity' become velocity with respect to something else? In GPS, the earth is not an absolute frame. It is a <I><B>prefered</B></I> frame.

 

Ha Ha indeed and do you contest that the orbit velocity is absolute in respect to the ECI? I think not. Now laugh out the other side.

Further more you have not commented on the fact that GPS relies on a third common frame of rest.


PS: I have many times referred to the ECI as a preferred frame myself. Don't be impertnent. That does not alter the fact that the orbit velocity is absolute in referance to it.

It is that absoluteness that prohibits the SRT view that the earth surface clock has all motion and that the orbiting clock is at rest such that the earth surface clock should run slow (due to velocity) rather than the other way around.

GPS shows that absolute relative motion is the correct view and not the over-simplified SRT view of just relative velocity.

Reciprocity does not exist. Otherwise GPS could not synchronize clocks. SRT is false. Simple really.

 

Look, how can anything be absolute w.r.t anything else. 'Absolute' means absolute, not w.r.t any damn frame or point. Either you've got the word wrong, or you've got the idea wrong.

 

Sorry your ability of reasoning seems so limited. Is the velocity of orbit of a GPS satellite absolute relative to the earth's center or not?

Is it not more appropriate to differentiate that fact than to simply say relative velocity as is done in SRT where such velocity inherently then includes the false and impossible fact of reciprocity claimed and advocated by SRT?

Yes "Absolute Relative Velocity" is a MacM term but it is long overdue that you and others start to understand the fact that relative velocity in of itself tells you nothing about relatvistic affects unless taken to a third common point of rest. A preferred frame. That preferred frame has no absolute characteristics universally but that is of no consequence or concern.

 

I'm not sure what you mean when you say 'absolute'. If you mean that it does not change when observed from earth, I thnk that's called 'uniform'. No, I don't think I can understand your usage. Please clarify.