Alternative Models of Reality

James Putnam

Hi Peter,

Sorry about that. I have read this before by you:

"The other essential parameter is TIME. You are actually wrong to state that B receives 'more energy' that A emitted, because the 'period' B received the energy over is simply shorter. It's the same energy, just more concentrated, so the periods 'each side' of the shorter charge contained less energy, balancing the totals over equivalent time.

All 'particles' are non zero in size (wavelength), and at interaction is an evolution over non-zero time. Both the size and time are so small we've simply missed that fact. Doppler blue shift is then simply a 'compression' of the energy ('length contraction' in SR) and redshift a 'dilation' (including of time signals)."

It looks wrong to me so I didn't include it. I do believe that your model does not violate the conservation of energy. That had been a concern of my own in the past when we communicated about your model. I kept what I said minimal to avoid causing confusion. I think what I said is correct. However, it is interesting that you are saying that you are explaining the Doppler effect as not increasing the energy but only compressing the time during which it is received. Is this compressed explanation correct from your point of view?

I hope that what we have written, especially your responses, helps to make what you are saying about your model clearer to the others.

James Putnam

pjackson

James,

Contracting a wave contracts it's energy. All waves still travel at c. I mentioned the multiple 'cases', and believe not distinguishing between them is why you think it 'looks wrong'. Ergo;

If two emitters, side by side, each emit one photon per nanosec, but one emits high energy (short 'blue' wavelength) and the other low (red), then because they then ARRIVE at the SAME FREQUENCY, the blue shifted photons will impart a higher charge. This is easy to be confused about as wave peak arrival rate can ALSO be expressed in 'frequency'.

It is then all about 'WAVENUMBER' 'N' (an important conserved quantity in optics). For any given amplitude it in 'N' that defines the energy. So;

In the case I've just described; where the same number of photons are emitted but at different wavelengths, the wavenumber so ENERGY of the blue ones is higher. The same number received as charge are re-emitted.

BUT; In the case previously discussed, where the same emitter photons are compressed or dilated in the new 'discrete field', (so red OR blue), the total wavenumber, so ENERGY, is the same, so is still conserved.

I hope that's distinguished OK and removed any confusion. Does that alleviate your doubts, or was it something else?

Remember there are also other differences, such as amplitude, which affects the ratio, but best to get the above fully assimilated before adding more cases!

I don'y now if anyone else is reading and keeping up with this. If so, you're doing very well! If not just ask questions.

Peter

Akinbo Ojo

James,

Your F = ma poser is well formulated and brings up the interesting question whether Force, F and mass, m can be reduced to the more fundamental length and time.

In this regard, one may note that hardly anything that has mass will not have length, whereas not all that is lengthy has mass. Again by E = MC2, what is massive can become massless, but even the massless must occupy some space, i.e. length.

Force is the more difficult of the two. Firstly, there can be no force unless it is opposed by another force. So in a sense, one may assume force does not actually exist as a fundamental thing but is merely an expression of some conservation principle. Perhaps, it is then this principle that requires length and time for its existence.

Then as to your position that light accelerates... if acceleration means rate of change in velocity, then if there is no resistance will light velocity become infinite? Also when light moves from air to glass will you call this deceleration? If you do, and the glass is of sufficient enough length, will the light not eventually be brought to rest in the glass given s = ut 1/2at^2? Such a scenario has never occurred. Rather what we see is light having a lower velocity in glass and a higher one in air, but not by acceleration.

Thomas Ray

"Acceleration doesn't need to be defined. It consists of measures of length and time."

Define "measures."

James Putnam

"Define "measures."

Meters and seconds. They have physical standards because they cannot be defined.

James Putnam

Akinbo,

Taking one point at a time:

"Your F = ma poser is well formulated and brings up the interesting question whether Force, F and mass, m can be reduced to the more fundamental length and time."

The answer is yes. That is what I have done and put to use redeveloping the fundamentals of physics. This is what I mean when I speak of theory free physics. There have been three properties by which all other properties of mechanics have been defined. Those three are length, time, and mass. Two of those, length and time, are naturally indefinable properties. They are the properties of empirical evidence. The empirical evidence is acceleration. There are no pre-existing properties by which either length or time can be defined. That is why they have arbitrary physical standards.

The third property, mass, is artificially indefinable. There should not be any artificial indefinable properties. The indefinable status of mass is a theory. It is a guess about how to proceed when one cannot see direction from empirical evidence. That guessing process is what theory consists of. By the act of defining mass in the terms of its empirical evidence, theory is removed from f=ma. Afterwards, all properties of mechanics are defined using only two truly fundamental indefinable properties, length and time. The new units for the defined property of mass are those of inverse acceleration. Force is then defined as a ratio of two accelerations. All other properties of mechanics are then defined using combinations of meters and seconds only. There is of course much more to be said.

James Putnam

Akinbo,

"In this regard, one may note that hardly anything that has mass will not have length, whereas not all that is lengthy has mass. Again by E = MC2, what is massive can become massless, but even the massless must occupy some space, i.e. length."

That I don't understand.

"Force is the more difficult of the two. Firstly, there can be no force unless it is opposed by another force. So in a sense, one may assume force does not actually exist as a fundamental thing but is merely an expression of some conservation principle. Perhaps, it is then this principle that requires length and time for its existence."

This is expressed very clearly for me and is correct. There is a conservation principle at work. It is a conservation of acceleration. For example light slows its speed as it approaches the Earth. A freely falling object gains in speed that which light loses. The acceleration of a freely falling object is equal but opposite to the acceleration of light. What light gives up, the object gains.

James Putnam

Akinbo,

"Then as to your position that light accelerates... if acceleration means rate of change in velocity, then if there is no resistance will light velocity become infinite? Also when light moves from air to glass will you call this deceleration? If you do, and the glass is of sufficient enough length, will the light not eventually be brought to rest in the glass given s = ut 1/2at^2? Such a scenario has never occurred. Rather what we see is light having a lower velocity in glass and a higher one in air, but not by acceleration."

The variation of the speed of light is the single original cause for all mechanical effects. It is the property of fundamental unity. When mass is correctly defined in f=ma, we achieve fundamental unity. That unity is constantly seen in the definitions of all other mechanical properties. Fundamental unity is a clearly seen part of all physics equations after they are redeveloped beginning with f=ma as their guide.

Light slows when it enters glass. It does not continue slowing. It has an average speed in glass. It slows because of its close proximity to mass. Length also shortens inside glass. For an observer inside the glass who is measuring the speed of light locally, they will measure the speed as C. Light always measures locally as C.

Both length and time are properties that are represented by the speed of light. In the case of length, it shortens as light slows. In the case of time, it is a constant as experienced by light. As for time dilation, it is the slowing of processes due to the slowing of light. It is light that is holding atoms together. Light determines the size of an atom. Light controls the speed at which an atom functions. A change in the speed of light results in changes in atomic size and rate of activity.

James Putnam

There are three properties that need to change in order to reformulate physics equations into their empirical forms. The first is being currently written about here with more to follow. It is the act of making mass a defined property and learning that the empirical units of mass are those of inverse acceleration. The second property of temperature is similar to mass in that it is currently a fundamental indefinable property. Its units of degrees are artificially made indefinable.

That is why explanations about what is temperature begin with the words 'It is a measure of...'. That 'of' property is always something other than temperature such as saying that temperature is a measure of average kinetic molecular energy. It is average molecular energy that is a measure of average molecular kinetic energy. Temperature doesn't have units of Joules because temperature is something other than energy. Temperature is proportional to average molecular kinetic energy. Fixing the units of temperature by learning how to define temperature in terms of empirical evidence results in units of meters/second. Only in this case meters represents the reduced form of the units of energy.

The units of energy are those of the product of force and length which are, in full empirical units, (meters/second2/meters/second2)(meters) which is, in its reduced form, just meters. The empirical units of temperature are those of the rate of exchange of average molecular kinetic energy between molecules. Temperature is the rate of exchange of average molecular kinetic energy between molecules.

James Putnam

The immediate benefit of defining temperature, other than learning what it is, is that a property defined in terms that include temperature can also now become understood. An important such property is thermodynamic entropy. It is not known what thermodynamic entropy is. That is why, just as with temperature, attempts at explaining it begin with the words 'It is a measure of...'. As with temperature, it is not a measure of something else. It may be proportional to something else, but it is itself unknown.

Its new empirical units help show what thermodynamic temperature is. Its definition is energy/temperature. Now that it is known that temperature has units of meters/second and energy has units of meters, it can be immediately seen that the empirical units of thermodynamic entropy are seconds. Its units fit with its definition. In order to understand its definition as a length of time, one must be familiar with what an ideal gas it. The important point about an ideal gas is that its pressure is very low. Gases in general behave like an ideal gas as their pressures become very low. The ideal gas must have a constant temperature throughout.

The temperature is the rate of exchange of average kinetic energy between molecules. As the pressure of the gas is made lower and lower it reaches a crucial temperature. That temperature is the key to Clausius's definition of thermodynamic entropy. The key temperature is the rate of exchange of average kinetic energy between molecules at the rate equal to that which would occur if all the molecules of the gas were lined up one after another with no gaps and passed their kinetic energy to the next molecule, one after the other, until the total number of molecules is reached.

Two related pieces of information. Boltxmann's constant is the time it takes for one molecule to pass its kinetic energy to another single molecule. The universal gas constant is the total time required for average kinetic energy to be passed from molecule to molecule, one after the other, until the number of molecules in a mole of gas, Avogadro's number, is reached. That is the kind of information that falls out of reforming the equations of physics into their empirical forms. It begins with fixing f=ma. The fix for f=ma is to define mass.

James Putnam

Richard Lewis

I would like to see if I have understood the issues raised in this thread and try to make a useful contribution. I have a copy of the book Relativity The Special and the General Theory by Albert Einstein and chapter 20 is titled The Equality of Inertial and Gravitational Mass as an Argument for the General Postulate of Relativity.

In this chapter Einstein describes a chest resembling a room with an observer. The chest has a hook with a rope attached and the chest is pulled by a constant force resulting in a uniform accelerated motion. He goes on to explain that the observer comes to the conclusion that the chest is suspended at rest in a gravitational field. There is more description than this but this is the essence of the example.

In the thread discussion it was stated that the forces that the observer will feel in the two cases are different. Let us imagine trying to set up an experiment within the chest to determine which case we are dealing with, accelerated motion or a gravitational field. Lets take four 1kg objects and place them one above the other with a compressible spring connecting them. This spring has the property that it has negligible mass and by the extent of its compression we can determine the compression force.

Now in the case of the objects in the gravitational field we can see that the lowest spring has 3kg above it and will be compressed to 3kg. The next spring will be compressed to 2kg and the topmost spring will be compressed to 1kg. Now consider the case where the chest containing the objects is being subjected to a uniform acceleration of one g to simulate Earth gravity. Then we can see that the topmost object of 1kg is being accelerated by one g by the force transmitted by the topmost spring so this spring must be compressed to 1kg. Similarly the next spring has a 2kg mass above it and so this spring will be compressed to 2kg and by a similar argument the lowest spring is compressed to 3kg. In both cases the force between the floor of the chest and the lowest object will be 4kg.

We can see that by this experiment we can not distinguish between the two cases (gravity and acceleration). Although the objects in the gravitational field are each acted upon individually by the field by virtue of their gravitational mass we can also see that the objects in a uniform acceleration each have their own inertial mass which is apparent when the objects are accelerated.

This example leads me to believe that the observer would not be able to feel any difference between the chest being in a uniform gravitational field and the chest being in uniform acceleration.

I would like to say a bit about the force aspect of the thread in my next post.

Richard

Thomas Ray

"This example leads me to believe that the observer would not be able to feel any difference between the chest being in a uniform gravitational field and the chest being in uniform acceleration."

Absolutely correct, Richard. It's a great book, everyone should read and study it.

Best,

Tom

Richard Lewis

Is the force of gravity fundamentally different from other forces of nature?

In one of the posts in this thread it was stated:

"Is the acceleration of a charged particle due to electric force?" Yes.

"Is the acceleration due to gravity caused by the force of gravity?" No.

"Are they both forces? If one is not a force, why not?"

I see the distinction as follows: There is a force of gravity and we can measure it. As a result of the General Theory of Relativity we now understand the cause of the force as due to the curvature of spacetime so we can say that the gravitational force is not a fundamental thing as we can see that it has an underlying cause.

There is an electrostatic force which we can measure. Do we really understand the cause of the electrostatic force? Not to the same depth of understanding as for gravitational force. In particle physics the concept of electric charge is considered a fundamental property without trying to explain the cause of electric charge. Without a full understanding of what electric charge is, we cannot really understand electrostatic force.

I have found one way of looking at the nature of force by considering energy differences. There is a common theme between the four fundamental forces that we can recognise the existence of a force by examining energy differences between possible configurations. The apple in the tree has a higher energy than the apple on the ground (gravitational force). Two electrons in close proximity have a higher energy than when they are further apart (electrostatic force). A proton and a neutron in close proximity have a lower energy than when they are further apart (mass deficit) (strong nuclear force).

My contention is that when we truly understand the nature of electric charge and the cause of the mass deficit by a deeper understanding of the nature of matter then it will become apparent that all the forces are related by the common theme that it is the geometry of spacetime and its variation which is the cause of all the four fundamental forces.

Richard

Thomas Ray

"My contention is that when we truly understand the nature of electric charge and the cause of the mass deficit by a deeper understanding of the nature of matter then it will become apparent that all the forces are related by the common theme that it is the geometry of spacetime and its variation which is the cause of all the four fundamental forces."

Bull's-eye again, Richard. On the large scale, Hawking's "no hair" theorem leaves a stable black hole with but three properties: mass, charge and angular momentum.

The mass deficit problem on the microscale (the measure of atomic binding energy, i.e., how much potential energy can be converted to pure kinetic energy) is another "hidden" quantity resulting from conservation of those fundamental physical quantities -- mass-energy, charge conjugation and angular momentum. How the geometry of spacetime limits those values within such a precise range is a compelling and beautiful proposition.

Best,

Tom

James Putnam

Hi Richard,

"I see the distinction as follows: There is a force of gravity and we can measure it. As a result of the General Theory of Relativity we now understand the cause of the force as due to the curvature of spacetime so we can say that the gravitational force is not a fundamental thing as we can see that it has an underlying cause."

You put theory forward as the distinction that establishes reality? My response is to ask you to report on any experiment performed on either space or time or what you refer to as space-time. Notice I am not asking for experimental data on objects that are not space or time or space-time.

James Putnam

Richard Lewis

Hi James,

I am not sure that I have understood your request for an experiment performed directly on spacetime without reference to objects. The closest I can think of is the famous verification of the general theory of relativity by observing the light from distant stars during a solar eclipse. Light provides a very good indicator of the curvature of spacetime but the experimental observation does involve objects such as the sun and the distant star.

The concept of reality is a bit tricky so I prefer to talk about whether a property e.g. force is fundamental or not. Something is not considered fundamental if it has a clearly identified underlying cause e.g. the force of gravity is caused by the curvature of spacetime due to other masses.

Please come back on this point if I have not addressed your point.

Richard

Richard Lewis

Hi Tom,

I have my own ideas on the nature of electric charge which is described in:

Electric charge

The basic idea is that an electron is a looped wave in the medium of spacetime. This interpretation fits in with the wave model of the electron which yields all the beautiful results of atomic spectra. The important new idea is that the waves are in spacetime so that as well as the space wave expanding and compressing space (local spacetime curvature) there is a wave variation in the time dimension.

This means that the rate of passage of time varies during each cycle of the wave so that there is a net component of expansion or compression. The area under the curve is used to represent this and it turns out to be independent of the mass of the particle so electrons and protons will have the same magnitude of charge. This net compression or expansion leads to a force of attraction or repulsion which is exactly the effect we observe as electric charge.

This I would place as the underlying cause of the electrostatic force which means that we no longer consider charge a fundamental property.

The parent web site is:

The nature of mass

Richard

James Putnam

Richard,

Hi again,

"The concept of reality is a bit tricky so I prefer to talk about whether a property e.g. force is fundamental or not. Something is not considered fundamental if it has a clearly identified underlying cause e.g. the force of gravity is caused by the curvature of spacetime due to other masses."

My point was that a clearly identified property should be falsifiable. In other words, if spacetime curves then its acceptance should depend upon experimental evidence that spacetime curves. The interactions of mass with light and light with mass and mass with mass are testable. Spacetime as an underlying cause is not testable. Such a test would require that space and time undergo testing on their own.

The empirical evidence for change is change of velocity with respect to time. Matter undergoes such verifiable change and light undergoes verifiable change. In other words, it is observed that their velocities change with respect to time. There is no evidence that either space or time or spacetime undergoes changes of velocity or even has velocity. So my point was that the claim that spacetime curvature is the cause of gravity is a purely theoretical explanation that cannot be falsified.

My apology for this condensed version of a long ongoing discussion. My position is that the door remains wide open for an alternative explanation that is falsifiable. It would probably help to make clear that I view theory as consisting of guesses about possible substitutes to serve in place of that which remains unknown in physics equations.

It has been my goal to remove those guesses from physics equations and return the equations back to their empirical forms. That is why I engage in discussions about fixing f=ma. The fundamental indefinable status of mass is one of those guesses. Hope that clarifies matters so that you can think about it or dismiss it depending upon your view of the value of theory.

James Putnam

Thomas Ray

"Spacetime as an underlying cause is not testable. Such a test would require that space and time undergo testing on their own."

That would be impossible, since space and time independently are not physically real. The tests of spacetime in general relativity, however, have been successfully met.

James Putnam

"That would be impossible, since space and time independently are not physically real. The tests of spacetime in general relativity, however, have been successfully met."

So there have been an experiment or experiments where the change of velocity of spacetime has been observed. What were the measured initial and final velocities of spacetime, and, what values of its acceleration were observed and recorded?

James Putnam

Richard Lewis

Hi James,

This is an attempt to reply to your statement that: A clearly identifiable property should be falsifiable. In other words if spacetime curves then its acceptance should be based on experimental evidence that spacetime curves.

I agree with your position on this but claim that the General Theory of relativity is falsifiable. The light from the distant star is bent around the sun to the amount predicted by GR. This is direct evidence that the sun curves spacetime. Other observations have been used to verify GR such as the observations of the change in the orbit of mercury.

I think that requiring direct testing of spacetime without the use of any other objects is impossible so I am content to accept that, once light has left a distant star it is travelling through space independently and acts as a good indicator of the curvature of spacetime.

It seems to me that you are questioning the validity of the general theory of relativity which was deduced by careful thought experiment and logical deduction and subsequently verified by observations. If I am right about this, can you tell me the alternative theory that you would put in place instead of GR?

Richard

Thomas Ray

Hi Richard,

I am not ignoring the very interesting links to your research. It's just too much for me to bite off at the moment.

Something occurred to me, relevant to your reply to James about testing the physical reality of spacetime, "I think that requiring direct testing of spacetime without the use of any other objects is impossible ..."

is true. However, besides the indirect testing of general relativity, I think there are other classical ways that imply spacetime is physically real. John brings up the case that compressing a volume of an ideal gas raises the temperature, and he claims (erroneously) that the measure of temperature is a physically real quantity.

Of course, we know that the work invested in compression is equal to the energy output measured as the temperature of the gas. Energy input-output from potential to kinetic in this case illustrates the relation of space -- taken as the bound volume -- to time. A slow compression rate allows the gas molecules time to store the energy by coming to relative rest (equilibrium), resulting in a phase transition from gas to liquid, and conversion of kinetic energy back into potential energy, released again as the kinetic energy of heat when the gas is uncompressed. So there's a very definite space-time cause associated with this cycle of effects -- a slower rate of time applied to a bound volume of space transfers more energy to the molecules than they would possess in a free state. While we can't speak of "molecules of space," we can speak in this context of energy stored and released in exact proportion to the time. Because the spatial distance input-output is symmetric, and the time input-output is symmetric -- the extension of spacetime to relativistic distances/velocities is natural.

Best,

Tom

James Putnam

Richard,

"...can you tell me the alternative theory that you would put in place instead of GR?"

Yes I could with a large amount of supporting work. However, it deals very strongly with finishing the unfinished fundamentals. otherwise, it is sometimes like talking in two different languages. I wrote some about this in an earlier message to you.

"My position is that the door remains wide open for an alternative explanation that is falsifiable. It would probably help to make clear that I view theory as consisting of guesses about possible substitutes to serve in place of that which remains unknown in physics equations.

Instead of my just jumping into providing answers to compete with higher level theory, it would help if we agreed on the importance of defining properties. I mention fixing f=ma by defining mass. Nature provides us with empirical evidence that fits with the decisions it made since the beginning of the universe. Nature didn't leave it up to us to decide that either force or mass would be an indefinable property joining the status of the indefinable properties of length and time.

Length and time are naturally indefinable by reason of their being the properties of empirical evidence. There are no properties before them by which they may be defined. The situation is very different for force and mass. They do have the pre-existing properties of length and time by which they may be defined. If that is not accomplished then a guess is the only other option. The guess option won out. The guess was that either force or mass would need to be made an indefinable property. That means that we did not learn what mass is from the empirical evidence. We instead invented a third indefinable property, mass, joining the status of length and time. Mass pops into existence without explanation.

It was the first intrusion of theory onto a physics equation. Instead of the equation representing that which empirical evidence is communicating to us, f=ma combines empirical evidence with human invention. The equation is changed from an empirical equation into one that is made subservient to a theory. The theory is that mass is a fundamental indefinable property. The answer to the question you posed lies in correctly defining mass. The correct definition of mass tells us what the cause for all effects is. I will end it here unless there is interest.

James Putnam

Quantum Antigravity

Hello,

I have made a theoretical as well as an empirical scientific discovery of quantum gravity and quantum antigravity.

Present quantum gravity theories suffer from too many space dimensions, and from too few experiments that could provide conclusive verifying, or falsifying empirical evidence. On the contrary, my hypothesis is simple, clear, and easily empirically verifiable:

https://quantumantigravity.wordpress.com

Should anybody need clarification, I am more than happy to answer any questions.

Naturally, I am also open to meritorious criticism, and any suggestions for improvement.

I am sure other researchers could greatly contribute to further development of this hypothesis (almost a theory).

Thank you so very much! :)

Thomas Ray

"'Define 'measures.'

"Meters and seconds. They have physical standards because they cannot be defined."

Then a meter could be the diameter of the universe and a second could be eternity. The standards of measurement are our conventions, James, not nature's.

In fact, mathematically, the diameter of the universe is length 1, and for the speed of light particles stretching that length, eternity is not differentiable from a single second.

pjackson

Richard,

You made the same assumption as Einstein, choosing a consistent case, but that is to ignore the real difference between the cases.

In the 'chest and string' scenario the body inside, (assuming he's not glued to the floor!) will not be accelerated until the end wall of the chest makes contact with him, so compresses him from one side.

This is then equivalent to your hanging springs and weights hanging above the roof of a lift and being accelerated from the bottom up when the lift starts off, and throughout acceleration.

We assume gravity doesn't act in this way when acting in free space, as proved by the lack of compressive force on the body. Now when the body lies on the ground it does appear to do so. It is the fact that there is ALSO a relative accelerative effect acting on the whole mass equally when in free space that is the difference between the two. Subtle, but I suggest a real physical difference we must examine and understand none the less.

I believe that expresses James's point, but I may be wrong. I thn also point out that speed can also be both relative ('co-ordinate') and 'propagation' (local c), which subtle but crucial point Einstein similarly 'missed'. Space is a medium. Diffuse, but big enough so that doesn't matter. Einstein couldn't have known this. We do so have no excuse!

Peter

Thomas Ray

"This is then equivalent to your hanging springs and weights hanging above the roof of a lift and being accelerated from the bottom up when the lift starts off, and throughout acceleration."

The thought experiment assumes continuous, uniform acceleration. It has nothing to do with an actual elevator starting from rest.

Richard Lewis

Hi Peter,

In my example, the objects and springs are located at the floor of the chest at the start of the experiment. If we assume that the chest is already in a state of uniform acceleration when the experiment involving the objects and springs are placed on the floor of the chest then I do not see any difference between the two cases that could be measured by the observer within the chest.

In fact I can not think of any experiment that could be performed within the confines of the chest to distinguish between the two cases of a uniform gravitational field and uniform acceleration.

I did not understand your point that:

It is the fact that there is ALSO a relative accelerative effect acting on the whole mass equally when in free space that is the difference between the two.

Richard

pjackson

Tom, Richard

Continuous uniform acceleration of the lift or box does the same.

In the lift case the springs will be compressed, as they would be when 'at rest' on the ground in a gravitational field. If 'hung' then they are equally under tension, but of course a body in a hung box would feel the same as on the ground.

BUT we must consider and compare with the case of acceleration by gravity in 'free fall'. This is that subtle but important non-equivalence; There is acceleration but ZERO compression or dilation effect on the body.

In the 'chest' case we must remove friction by considering the body to be on ice, or floating in water. You then described the case for constant motion (a 'rest frame'), but not for constant ACCELERATION. In the continuing acceleration case the body will always slide to the back of the case and be under compression from the back wall of the chest. i.e.

There is no case of a body under normal constant acceleration which is entirely equivalent (in terms of effects on the body) to the free fall case in gravity.

As Einstein didn't fully discern and analyse the subtle difference, It's no surprise it's tricky for mere mortals!

Richard Re; "...acting on the whole mass equally..." Hopefully that emerges from the above. The point is about what a body 'feels'. It can 'feel' the pull and push, of acceleration involving compression and dilation. The difference is that in free fall it feels nothing as every particle is being 'acted on' equally at once. (There are also complex subtleties to the concept 'acted on').

The book you refer is only a small and early part of his works. I'd suggest you could very usefully also read the 'Notes to the 15th edition' as giving his far more considered and final views, concepts and rationalisations.

Best wishes

Peter

Thomas Ray

"There is no case of a body under normal constant acceleration which is entirely equivalent (in terms of effects on the body) to the free fall case in gravity."

Every body in gravitational free fall accelerates at a rate dependent on the strength of the field, precisely calculable by the inverse square law.

"As Einstein didn't fully discern and analyse the subtle difference, It's no surprise it's tricky for mere mortals!"

Poor old Albert. The loser.

Best,

Tom

Richard Lewis

Hi Peter,

I thought we were comparing the cases where the chest is under uniform acceleration with the case where the chest is at rest in a uniform gravitational field. I am satisfied that the observer inside the chest will not be able to detect any difference between these two cases.

If the chest is in free fall in a uniform gravitational field, this would feel the same as if the chest is at rest with no gravitational field. The observer inside the chest feels no gravity or acceleration and so feels weightless.

Richard

pjackson

Richard,

Precisely. That case what Tom's missing, or avoiding Tom?

For complete equivalence we must compare like with like. The case you first chose is fine, but full equivalence means that; "If the chest is in free fall in a uniform gravitational field," (i.e. being accelerated by gravity) then there should be an equivalent "acceleration" case (NOT by gravity). But there is not.

More importantly; There is no case of non gravitational acceleration where the EFFECT FELT BY A BODY is equivalent. So there is a subtle difference which may be of great help in better understanding gravity (which nobody denies is needed!).

If we avert our eyes and pretend that difference doesn't exist then I suggest we're not doing science and can't apply our intellect to improve our knowledge. Is that not a fair comment?

I've gone beyond this and considered assumptions about momentum and inertia in more detail which seems to give insights. But let's ensure you understand what we are discussing before (if you wish) moving on.

A Hint; Have you ever considered the issue (under the carpet) that E=mc^2 and it's converse equivalent M=e/c^2 use different descriptions of mass, rest and inertial, which vary? The postulates seem to emerge from a possible resolution without the apparent paradoxes attached.

Peter

Thomas Ray

"Have you ever considered the issue (under the carpet) that E=mc^2 and it's converse equivalent M=e/c^2 use different descriptions of mass, rest and inertial, which vary?"

No, because they don't. The equation for mass-energy at rest, E_0 = mc^2 is precisely the same as m = E_0/c^2. What you're assuming without justification, Peter, is that algebraic manipulation creates a different physical description. You are not understanding that rest mass-energy is a singular quantity that varies according to the amount of rest energy converted from potential energy to kinetic energy.

Best,

Tom

Richard Lewis

Hi Peter,

"If the chest is in free fall in a uniform gravitational field," (i.e. being accelerated by gravity) then there should be an equivalent "acceleration" case (NOT by gravity). But there is not.

I dont agree with your assertion.

As I see it the point is that when the chest is in free fall then the perception of the observer inside the box is that he is at rest without gravity or acceleration and freely floating in space. I dont understand why you think that there should be an equivalent acceleration case.

If we were to start to accelerate the chest which is not in a gravitational field by say a third of one g then we are no longer equivalent to the case of the chest in free fall in a uniform gravitational field. In this case the observer inside would experience a third of one g. This would be equivalent to the chest being in a uniform gravitational field of one g with an externally applied acceleration of two thirds g in the direction of motion so that the observer inside the chest experiences a third of one g. A bit like the feeling when you initially descend in an elevator.

This illustrates the point that you can compare two cases where there is acceleration. However, the gravitational field accounts for one g so naturally there is always a difference of one g when comparing the movement of the chest in a gravitational field or no gravitational field.

Richard

James Putnam

The natural standard for time, in terms of seconds, is 1.602x10-19. It is the time for light to travel the radius of the hydrogen atom. Its symbol is tc = one photon time.

The natural standard for length, in terms of meters, is 4.8x10-11, It is the size of the radius of the hydrogen atom. Its symbol is lc = one photon length.

Now the big one, mass, without theory. Just as the speed of light always measures the same locally, so does its acceleration. The natural standard for mass is the inverse of the acceleration of light measured locally. The local acceleration of light is calculated as 1/C/tc = tc/C = 5.344x10-28sec2/m or kilograms. Its symbol is ml = one standard mass.

James Putnam

Thomas Ray

James, what makes these values "natural" rather than arbitrary?

There are, after all, more fundamental physical objects than a hydrogen atom.

Best,

Tom

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