Abstract
The discussion centres on the distinction between motion and acceleration in the context of relativity. While motion is deemed relative, dependent on a frame of reference, acceleration is asserted to be absolute due to the involvement of forces.
However, this perspective is challenged, as the absence of a universally recognised frame of reference makes defining absolute acceleration problematic.
The term ‘absolute acceleration’ has nothing to do with acceleration as normally conceived, leading to confusion in terminology and the theory of physics itself.
Ultimately, the argument suggests that reference frames are abstract constructs that do not effectively contribute to our understanding of physical reality or its phenomena.
An alternative scheme is suggested which describes motion and acceleration as physical processes rather than coordinate phenomena.
Motivation
I asked an AI engine: “If all motion is relative then does it follow that all acceleration is relative?”
The answer is a load of gobbledygook nonsense but is well referenced and does in fact reflect the opinions of many contemporary physicists:
AI response:
“While the principle of relativity dictates that motion is relative (you can only measure speed and direction relative to another object), acceleration is absolute.
Because acceleration involves forces and changes in velocity, it is not relative. You can always tell if you are accelerating without needing to look outside your frame of reference.
Here is the breakdown of why this distinction exists:
- Inertial Frames: When an object is moving at a constant velocity (or is completely still), it is in an inertial frame. Within this frame, the laws of physics work the same, and there is no physical experiment you can do to determine your absolute speed.
- Non-Inertial Frames: When an object accelerates (whether speeding up, slowing down, or changing direction), it enters a non-inertial frame. In this state, “fictitious forces” appear. For example, if you are in a car that slams on the brakes, you feel a force pushing you forward, even though no outside force is physically touching your body.
Because of these physical forces, absolute acceleration can be measured locally (for example, using an accelerometer) without comparing your movement to any external object or coordinate system.
Does any of this sound at all reasonable?
All the responses by the engine can be found in texts on relativity and seem to be accepted as accurate representations of Reality even though they make no sense whatsoever.
Motion is relative but acceleration is absolute?
“While the principle of relativity dictates that motion is relative (you can only measure speed and direction relative to another object), acceleration is absolute”
Acceleration is commonly defined as a change in velocity with respect to time, so if we have no definition of absolute motion it naturally follows that we have no definition of absolute acceleration.
“Because acceleration involves forces and changes in velocity, it is not relative. “
If acceleration involves changes in velocity and velocity is relative then acceleration must also be relative. If three objects are floating in space and are drawn together by gravity then they are all accelerating relative to each other but none of the accelerations can be said to be ‘absolute’.
“Because acceleration involves forces..” No! Acceleration is defined as a change in velocity with respect to time. This is a definition dependent solely upon the coordinate system. ‘Forces’ have nothing to do with the definition and the application of a force to an object does not suddenly make the acceleration ‘absolute’.
“You can always tell if you are accelerating without needing to look outside your frame of reference. ” Again: No! Acceleration as normally defined is purely a function of the frame of reference (a coordinate system); a different frame of reference would lead to a different measure of acceleration. If the acceleration is accepted as ‘absolute’ then the frame of reference must also be regarded as ‘absolute’ and so we should ask what it means to ‘look outside your frame of reference‘.
If acceleration is purely a coordinate phenomenon then an ‘absolute’ acceleration implies the existence of an ‘absolute’ coordinate system. However, no such thing exists.
Newton’s bucket experiment
Newton half filled a bucket with water and spun it on the end of a rope to see the water form a whirlpool and climb the sides of the bucket. The behaviour of the water can be explained in terms of inertia, acceleration and centrifugal forces but all of these require the a priori definition of a coordinate system for their unambiguous description.
Now since acceleration, and by extension, rotary motion are said to be absolute, we need to find an absolute frame of reference with respect to which they can be defined.
No such absolute frame of reference has been delineated by physicists and so we are left without an unambiguous definition of acceleration.
The distant stars..
A first try at defining a coordinate system was with respect to the ‘fixed stars’ but with the realisation that the stars were not fixed this was changed to the ‘distant stars’.
Physicists still rely on this concept today as a sort of sticky-plaster mechanism to hold everything together but a change of terminology doesn’t solve the problem.
The distant stars are moving away from us at great speeds and are accelerating all the time at different rates and in different directions. Any attempt to define a coordinate system with reference to this is palpable nonsense.
Imagine floating alone in deep space, how can you tell if you are stationary or moving at 1000 k.p.h.?
No absolute frame of reference
To summarise then: There is no consistent definition of anything that might be described as an absolute frame of reference or coordinate system within which we might delineate coordinate phenomena such as motion, rotational motion or acceleration as ‘absolute’ in any meaningful sense of the word.
The folklore of physics uses these terms all the time, but if we are to be precise, none of them has been ascribed an unambiguous meaning and so the whole of cosmology, in particular, has little relationship to actual reality.
Inertial frames
From the AI summary: “When an object is moving at a constant velocity (or is completely still), it is in an inertial frame. Within this frame, the laws of physics work the same, and there is no physical experiment you can do to determine your absolute speed.”
Since no coordinate system has been established by which to define velocity:
- There is no such scientific concept as “constant velocity“
- There is no such scientific concept as “completely still“
- There is no definition of an “inertial frame”
- There is no “absolute speed” to be determined
- The laws of physics are undefined
Non-inertial frames
From the AI summary: “When an object accelerates (whether speeding up, slowing down, or changing direction), it enters a non-inertial frame. In this state, “fictitious forces” appear. For example, if you are in a car that slams on the brakes, you feel a force pushing you forward, even though no outside force is physically touching your body.”
We have seen that there is no consistently defined absolute frame of reference with respect to which acceleration can be defined. Therefore:
- There is no consistent definition of acceleration. Ergo..
- There is no consistent definition of an inertial frame
We were told that “.. acceleration involves forces and changes in velocity“. However, the above now downplays the existence of such forces to “fictitious forces“.
These presumably are not ‘real’ but nevertheless seem to have some impact upon physical reality and seem essential for explaining the motion of physical bodies. Why is gravity deemed a ‘real’ force and yet centrifugal force considered to be ‘fictitious’?
Reference frames are imaginary measuring tools; there is no ‘entering an inertial frame‘ as inertial frames are not real.
Absolute acceleration
“Because of these physical forces, absolute acceleration can be measured locally (for example, using an accelerometer) without comparing your movement to any external object or coordinate system.”
‘Absolute acceleration‘ as derived from coordinate measurements has not been defined and so there is nothing here to be measured either with or without an accelerometer.
Relative acceleration is defined relative to another object but cannot be measured by an accelerometer.
Moreover, it has been conceded that the physical forces may be fictitious forces and these, again, are undefined. How does one determine if a force is fictitious or not? Presumably we look to see if it causes absolute acceleration – but such a thing is undefined!
Note that gravity will not be detected as absolute acceleration but a (fictitious) centrifugal force will. Go figure!
General relativity
Einstein’s theory of special relativity treated all motion as relative and tried to formulate acceleration as a coordinate phenomenon, but encountered all the problems we read about above: Einstein’s relativity vs. actual reality
The theory of general relativity, however, defines proper acceleration as “that which is measured by an accelerometer”.
Wow!
So a form of acceleration has been defined which has nothing to do with the change of velocity with respect to time. The term is ‘proper acceleration‘ and the word ‘acceleration’ is presumably retained to give the impression that this is somehow the same phenomenon as coordinate acceleration but viewed from a different perspective.
This is deceptive. The two phenomena are only the same if we accept Newton’s law:
force = mass x acceleration
.. the problem being that acceleration is undefined, force may be fictitious and gravitational mass is unmeasurable: Gravity debunked
(fictitious force) = (unmeasurable mass) x (undefined acceleration)
Proper acceleration is local only
Proper/local/absolute acceleration is measured locally by an accelerometer and has nothing to do with speed, distance, coordinate systems or orbitals.
Imagine you are interested in cosmology for some reason and you want to explain the orbitals of the planets. You cannot install an accelerometer on a distant planet and so must deduce its acceleration by observing its ‘movement‘ and ‘change of movement over time‘. In other words you must revert to the original concepts of velocity and acceleration as coordinate phenomena.
Proper acceleration is a useless concept here. Moreover, all coordinate measurements are relative to the planet Earth and so are not in any way to be considered ‘absolute’.
An example
An observer at the Earth’s surface sees two astronauts spaced some distance apart but falling towards the planet from a great height.
The observer measures positive proper acceleration at the surface of the planet but considers himself to be stationary.
Both astronauts measure zero proper acceleration and so do not consider themselves to be accelerating in an absolute sense. However, both astronauts consider that the other is accelerating towards them whilst at the same time the Earth also appears to be accelerating rapidly nearer.
In terms of coordinate physics, the Earthly observer measures both astronauts as accelerating towards the Earth and towards each other.
We see that coordinate acceleration and proper acceleration have very little to do with each other and a body can possess either one of these without the other. The use of the same word, ‘acceleration’ for both phenomena is clearly misleading.
Moreover, there is still no ‘absolute’ frame of reference by which to make measurements, no way to describe rotational movement, no way to distinguish ‘fictitious’ from ‘real’ forces and hence no way to determine if Newton’s laws actually hold.
Velocity
From the AI response: “When an object is moving at a constant velocity (or is completely still), it is in an inertial frame..”
What is meant by “constant velocity” here or “completely still”? It has already been claimed that all velocity is relative and so these terms have no meaning.
From AI: “.. Within this frame, the laws of physics work the same, and there is no physical experiment you can do to determine your absolute speed“
But you have no ‘absolute speed‘ according to relativity and so there is nothing here to be determined.
We are told that “the laws of physics work the same” but what is meant by “the laws of physics“? Does this just mean Newton’s laws or some absolute set of laws that have yet to be described? It is evident from the above that Newton’s laws depend upon some absolute coordinate system which has yet to be determined and so the phrase “the laws of physics” is technically meaningless.
Einstein’s reference frames
I asked an AI engine again: “Do Einstein’s reference frames have any causal influence upon physical processes?”
The reply:
“No. Einstein’s reference frames do not have any causal influence upon physical processes.
“In physics, a reference frame is a mathematical coordinate system used by an observer to measure positions, times, velocities. It is a tool for bookkeeping, not a physical object or a field.
- No physical interactions: A reference frame cannot push, pull, transfer energy, or exert forces on particles.
- The Principle of Relativity: Einstein’s core postulate states that the laws of physics are exactly the same in all inertial frames. Physical processes unfold due local interactions (like fields and forces), completely independent of how an observer chooses to look at them.
Response to AI
So a reference frame is is a mathematical abstraction and has no causal effect upon physical reality. It delineates no physical process and therefore adds no extra knowledge to any theory of physics. It takes no active (causal) part in any theory of physics and does not enhance the theory in any conceivable way. The study of reference frames is therefore an irrelevance to the study of the real world.
Physical processes unfold due to local interactions only, irrespective of the relative speed of an observer and this means irrespective of the choice of reference frame.
We are told: “In physics, a reference frame is a mathematical coordinate system used by an observer to measure positions, times, velocities. It is a tool for bookkeeping, not a physical object or a field.”
The questions then arises that if a reference frame is not a physical object then how, exactly, is it used by an observer to make measurements? What are the physical processes involved by which a measurement can be made?
If we measure distance, for example by stretching out a tape measure, then something physical has happened and the measured ‘distance’ is the outcome of such a physical process. However, a reference frame is not part of the physical world and cannot partake of it in any way. It follows that no physical measurements can be made via such an abstract construct and we are forced to conclude that reference frames are imaginary artefacts and completely useless from a practical point of view.
We can try thinking that measurements within a reference frame are something like the shadows on the back of Plato’s cave, which is to say they are representative of what s going on outside the cave and yet are not outside the cave. However, we still need light from outside the cave to illuminate the interior and thereby create the shadows. There is no parallel for this with reference frames and reality; physical events do not cast a shadow upon a cave-like reference frame.
What is Relativity?
In attempting to read texts on the subject of relativity we find that a great deal of effort is expended in explaining how physical reality appears from the point of view of different reference frames. Coordinates are converted from one reference frame to another via the famous Lorentz Transformation and a new theory of physics is claimed by the scientists.
After a while, theory is accepted as fact and Reference Frames are somehow accepted as genuinely representative of actual Reality.
However, as the AI engine has already explained:
“Physical processes unfold due local interactions (like fields and forces), completely independent of how an observer chooses to look at them.”
This is surely the single most important insight from the mechanical summariser, that physical processes (and hence the Laws of Physics) are independent of any frame of reference, coordinate system or any movement of an observer.
You cannot create an extra law of physics merely by moving at a different speed. You cannot influence physical processes by simply changing the reference system.
The study of coordinate systems is therefore independent of the study of physical processes and has nothing to do with actual reality. All downstream theories are similarly divorced from reality and are simply the meaningless fantasies of theoretical physicists.
These include:
- Length contraction
- Time dilation
- Twin paradoxes
- Black holes and big bangs
- Length, velocity and acceleration as coordinate phenomena
- Gravity as a coordinate phenomenon
- Bendy space-time
- Space-time
- Time (!)
These are all abstractions in coordinate-space which as we have seen, somewhat surprisingly, is unable to provide unambiguous descriptions of even the simplest of concepts such as velocity and acceleration.
All size is relative
This very short refutation of the Theory of Relativity comes from a comment somewhere on YouTube but I forget where:
Imagine two astronauts moving apart in space with each observing the other to be getting smaller. Einstein claims that they really are getting smaller and that actual (not apparent) size is now observer dependent. Einstein writes pages of barely comprehensible equations; gets Nobel prize.
Some solutions
Clearly something has gone very wrong and attempts to solve the problems created by coordinates by inventing even more coordinates have not helped.
Einstein is credited as having said: “We cannot solve our problems with the same thinking we used when we created them“, but even this appears not to be true; he didn’t say it.
Instead of looking for some absolute and yet mythical coordinate system we should consider the local gravitational field as a reference for movement and acceleration.
We can consider that it has two main components:
- A radial, accelerative component
- An isotropic inertial component
Explained here: Gravity as an inertial field
The following consequences follow naturally:
- There is no place in the Universe without such a field
- A gravitational field is a physical entity and not a coordinate system
- Velocity is now relative to such a field and can be thought of as a physical process consisting of interaction between matter and field
- Velocity relative to the field is unmeasurable with contemporary instruments but that does not mean it does not exist as a physical process
- Acceleration and inertia are physical processes consisting of of interaction between matter and field
- The gravitational field varies continuously throughout the universe which makes a description via a coordinate system somewhat irrelevant
- Reference frames may exist in special cases in limited areas of the cosmos, e.g. in a laboratory at the Earth’s surface
- Newton’s bucket spins within the gravitational field at the surface of the Earth and it is this field which confers ‘inertia’ upon the water
- Inertial and gravitational forces are in no way ‘fundamental’ but arise as a result of the interaction of field and matter
- Local inertial frames of reference are derived from the physical properties of the field rather than the other way around
- Coordinate systems are not causal in any way shape or form
- Physical processes unfold independently of the frame of reference and so may be considered to be ‘absolute’
- Physical processes replace coordinate systems as a description of physical reality