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Olorin

Time, Space & the Aether

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11 hours ago, Olorin said:

So what do you suppose tweaked Einstein's curiosity concerning the non-Euclidean, non-Newtonian, etc. properties of light (or more generally, the propagation of disturbances in the electric field (aether for want of a more appropriate term)?

That one's easy, and much less convoluted than the story about the CC. It was Maxwell's equations for electromagnetism. He actually didn't think in terms of 4-dimensional non-Euclidean space for quite a while, until Minkowski came up with his formalism of time as a fourth dimension.

For Einstein it was always Maxwell's great unification of electricity and magnetism what was the inspiration, and the experimental corroboration by Hertz. From then on, he always thought the equations must be correct, and must be telling us something very deep about Nature. The equations say the speed of light doesn't depend on the observer, so I'll take it to heart and see what the consequences are. Space and time must be changed to comply with these field equations? It must be it.

AAMOF, he conjectured gravitational field equations as kind of an analogue of EM --Maxwell's equations-- for curved spaces.

But two corrections about the currently accepted formalism --:

Light is not ether. In fact there is no ether, as has been proven to death. There is no lack of an appropriate term: Space-time is the accepted term. It has symmetry properties that explain a great deal of how light behaves.

The non-Euclidean character is not a property of the field, but of the space-time continuum. Fields are defined on it, so they inherit this structure.

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1 hour ago, SergUpstart said:

A very important property of pseudo-forces is that they are always proportional to the masses; the same is true for gravity.

The source of gravity in GR isn't mass, it's the energy-momentum tensor. All forms of energy (including, but not limited to, mass) contribute to the local geometry of spacetime, and all test particles are affected by that, not just massive ones.

1 hour ago, SergUpstart said:

Einstein put forward the famous hypothesis that acceleration causes an imitation (similarity) of gravity, that the acceleration forces (pseudo — forces) cannot be distinguished from the forces of gravity; it is impossible to say which part of a given force is gravity and which is pseudo — force.

The equivalence principle applies only locally in small enough reference frames; on larger scales, gravity is tidal in nature.

1 hour ago, SergUpstart said:

Although this picture does not concern the geometry of Euclid (it does not show us what is "wonderful" in it), it shows that by noticeably distorting the geometry, all gravity can be attributed to pseudo-force.

You can do this locally in a small enough region for massive test particles, but it is really much better to take gravity for what it actually is - geodesic deviation. This concept does not rely on any restrictions of scale, and applies to all cases, not just massive test particles. In my opinion, resorting to local definitions of pseudo-forces unnecessarily confuses things, it is much better and simpler to just stick to a purely geometric picture.

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3 hours ago, SergUpstart said:

Could it be that gravity is caused by the lack of a proper coordinate system?

Of course.
Consider a map of the Earth ( 2 dimensional Cartesian ) with two ants at the equator.
Both ants move directly North, they never meet, and there is no force between them acting at a distance.

Now consider a different co-ordinate system, where those same two ants are on a curved surface, such as a globe of the Earth ( still 2 dimensional, but now just the angular part of spherical polar, or latitude and longitude ). The ants again move directly North, but this time, they get closer and closer together, until they crash into each other at the North Pole.
And since they, like Newton, are not aware they're travelling on a curved surface, assume there is a force drawing them together, and acting at a distance. They call it gravity, but it is actually just paths along a curved manifold.

That is what GR tells us. Gravity is not a force, acting at a distance, but simply paths ( geodesics, worldlines ) along 4 dimensional space-time.

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5 hours ago, MigL said:

Of course.
Consider a map of the Earth ( 2 dimensional Cartesian ) with two ants at the equator.
Both ants move directly North, they never meet, and there is no force between them acting at a distance.

Now consider a different co-ordinate system, where those same two ants are on a curved surface, such as a globe of the Earth ( still 2 dimensional, but now just the angular part of spherical polar, or latitude and longitude ). The ants again move directly North, but this time, they get closer and closer together, until they crash into each other at the North Pole.
And since they, like Newton, are not aware they're travelling on a curved surface, assume there is a force drawing them together, and acting at a distance. They call it gravity, but it is actually just paths along a curved manifold.

That is what GR tells us. Gravity is not a force, acting at a distance, but simply paths ( geodesics, worldlines ) along 4 dimensional space-time.

There is a weight on the table. It is affected by the force of gravity and the reaction force of the table, which balance each other. But if gravity is not a force, then in response to what is the reaction force of the support?

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2 minutes ago, SergUpstart said:

There is a weight on the table. It is affected by the force of gravity and the reaction force of the table, which balance each other. But if gravity is not a force, then in response to what is the reaction force of the support?

If you are at rest in a gravitational field, you are not in an inertial frame.

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9 hours ago, swansont said:

Mainstream, basically, means you can find it in a textbook that is used in accredited universities. The aether only show up in an historical context of a disproven model.

I do understand the historical concept of an aether as the frame where light does vector c, and the disproven idea that all other frames moving at vector v relative to this frame having light doing c - v, knocked on the head by the failure of the Michelson-Morley experiment, and purportedly leading to a constant c. I have just read the treatise on pseudo forces above, separating gravity from electric forces as the cause of space-time. I have been trying to go back to first principles to perhaps untangle a physics that seems to me to be getting lost in semantics, and stalled, despite this well intentioned reply. In terms of pseudo-forces as explained above, there may only be pseudo forces and thus only one force. The aether in these terms is a timeless-spaceless source of the potentials and dynamic disturbances which manifest, not only the "pseudo-force" called gravity, but time and space themselves, relative to the material body of a specific observer in a particular frame, inertial or non-inertial. This makes my "aether frame", so defined, completely unobservable otherwise, except as the substance and source of what is observed, which is manifestation, the firmament, the universe and all of its phenomena, all expressed in space-time terms and derive-able laws we call science. And so - Einstein has said that "the universe may not have an existence independent of the observer" which he also stated as "science cannot determine whether the senses are some kind of psychic phenomenon" (no doubt paraphrased from memory but definitely from his writings and lectures). Thus, before matter in space-time existed except as a possibility in the Mind from which reason manifests in nature, the creation of 2 oppositely charged particles formed the force between them which we call an electric field, and the dynamics that became the Universe as matter and energy perfectly conserved and finite, is what we perceive. Is it real or a dream? What is the difference? One is shared by all, the other personal, the substance the same, and possible the purpose also. Anciently, light and consciousness were considered synonymous. Yea or nay is ours to determine and called free will. But this seems also to have been the opinion of Albert Einstein, and the source of his passion, genius and unquestionable humanity.

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13 hours ago, Olorin said:

No science fascinates me more than Special and General Relativity and the mind that produced them. Thanks for the reference. On this score I have posed a question critical to my views:

"OTOH, electric and magnetic fields are not the be-all-end-all of what can be in space.

I am going to take you are your words here for your interest and say +1 for this part of your post.

The thing is that the reference you alluded to is a biography (of a man).

Biographies are not always the best places to study the history and philosophy of a subject.
Obviously they provide the equivalent for the people.

Fields and Relativity and the so called 'action at a distance question' all have a history, separate from, but connected to many people and their biographies.

Here is a bibliography of the history and philosophy of these subjects (as well as the connnections to their author's bographies) you might find on interest.

Brfore the list a further note is in order.

Some of these authors are Mathematicians, setting the subjects in the context of pure mathematics and applying more general principles to the specific applications of Relativity and Fields.
Others work are Physicists and Philosophers and work in the other direction using the physical observation and reasoning from it to develop the appropriate Mathematics to describe it and predict new phenomena.
Yet others are the actual originators themselves.

(I would beware of Whittaker - he was a Mathematician, but he was rather biased in his treatments of the work of others.)

So The Physicists first.

James Clerk Maxwell     Matter and Motion, with appendices by Sir Joseph Larmour
James Clerk Maxwell     A Dynamical Theory of the Electromagnetic Field

Einstein                               The Principle of Relativity      This book is a collection of original papers by Einstein, Weyl, Minkowski and Lorentz with notes by Sommerfield

Pedro G Ferreirra             The Perfect Theory - A century of geniuses and the battle over General Relativity.   Ferreira is currently Professor of Astrophysics at Oxford.

Wilczek                                 The Lightness of Being   -  Nobel Physicist brings in his modern version of the aether, via Feynman and others.

Now the Mathematicians

Erwin Schrodinger           Space-Time Structure

Shlomo Sternberg           Dynamical Systems      A mathematical companion to Relativity, setting it in modern mathematical terms.

Finally  the Philosopher in the chapter onRelativity.

Sir Harold Jeffreys         Scientific Inference.  A good account of who new what, when they new it, and what that meant in the chaptern on relativity.

William Berkson              Fields of Force  -  the development of a World view from Faraday to Einstein.

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2 hours ago, swansont said:

If you are at rest in a gravitational field, you are not in an inertial frame.

That's right. But this means that gravity is still a force, at least pseudo.

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4 hours ago, SergUpstart said:

That's right. But this means that gravity is still a force, at least pseudo.

If G becomes resolve like the permeability constant as a function of the permittivity constant and the speed of light, it is my opinion that many of the problems of subatomic physics and astrophysics will evaporate, and the knowledge of the source from which all power comes will be ours again, to rebuild the Great Pyramid, or even to explain its existence, or the age of the stalagmites and stalactites in the Bahama Blue Holes. It may however, not be our fate to reacquire such power on this world, which likely is not our first to leave behind us, if the author of "Jap Herron" is to be believed (concerning the last note from Mark Twain at the end of the prologue "The coming of Jap Herron"). It promises to be a hard nut to swallow. The World has much to thank the US for besides in so many ways.  Thank you all for your input. Good luck with your ventures.

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13 hours ago, SergUpstart said:

But if gravity is not a force, then in response to what is the reaction force of the support?

The natural state of motion for all bodies is free fall - this is the state where no forces act on the body, i.e. it is a state in which a co-moving accelerometer reads exactly zero. In this scenario, the weight is prevented from freely falling by the surface of the table, so it is the table which exerts a force on it, not the other way around.

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4 minutes ago, Markus Hanke said:

. In this scenario, the weight is prevented from freely falling by the surface of the table, so it is the table which exerts a force on it, not the other way around.

With what force the weight acts on the table, with the same force the table acts on the weight, Newton's third law.

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3 hours ago, SergUpstart said:

With what force the weight acts on the table, with the same force the table acts on the weight, Newton's third law.

Yes, but that is only because you are in a non-inertial frame. The important point here isn't the table itself, but the fact that its presence prevents the test particle from remaining in its natural state of motion, being free fall. To put it differently, gravity "acts" on freely falling test particles (by determining their trajectories) even though a co-moving accelerometer reads exactly zero everywhere and at all times - meaning gravity isn't a force in the Newtonian sense. There are four main ways to look at this:

1. Kinematics. An accelerometer in free fall reads zero everywhere, so the equation of free fall motion is simply:

\[a^{\mu}=0\]

If we set up a local coordinate system, we can denote the position vector of our test particle as \(x^{\mu}(\tau)\), and the above then becomes

\[x{^{\mu }}{_{||\tau \tau }} =0\]

wherein the || denotes covariant differentiation, since we are in a curved spacetime. The solutions of this equation of motion are geodesics of spacetime, being free fall world lines. No need to reference the concept of "force" anywhere here - which would be difficult, since a=0 implies F=0.

2. Geometry. Rewrite the above equation as 

\[\nabla _{u}\vec{u} =0\]

This is the same equation as above, just written in terms of 4-velocity instead of acceleration. The geometric meaning of this is that free fall world lines are curves in spacetime that parallel-transport their own tangent vectors. Again, the concept of "force" does not come into this at all, it is purely geometric.

3. Pseudo-forces. Start with the equation in (1), and write out the covariant derivative fully in component form:

\[\frac{d^{2} x^{\mu }}{d\tau ^{2}} =-\Gamma ^{\mu }_{\alpha \beta }\frac{dx^{\alpha }}{d\tau }\frac{dx^{\beta }}{d\tau }\]

Again, this is the same equation, only written out fully. The left hand side is a Newtonian acceleration, the right hand side can be interpreted as pseudo-forces, which originate from the fact that the background spacetime is not flat. This is a valid way to look at this for massive particles; however, the right hand side of the equation taken on its own is not covariant, so it depends on the observer, and one can always locally eliminate the Christoffel symbol by going into the rest frame of the falling particle. Of course, this interpretation actually fails in the case of photons, since the very concept of Newtonian "pseudo-forces" is meaningless for massless particles.

4. Least action. Free fall world lines are those for which total proper time is an extremum, i.e. they are the longest (or shortest, depending on sign convention) possible world lines between two given events:

\[\tau =\int _{C} ds=\int ^{B}_{A}\sqrt{-g_{\mu \nu } dx^{\mu } dx^{\nu }} =\text{extremum}\]

This again does not require any notion of force.

If you look at all of the above ways to consider the geodesic equation (which is what this is), then you will find that the common factor in all of them is not force, but geometry. I have parametrised the test particle's world line by proper time here, but everything remains valid if you replace this by a more general affine parameter, in order to include massless test particles as well. Do note though that the "pseudo-forces" way to look at it is highly problematic in the case of massless particles.

The point I am trying to make is that it is best to look at gravity as a geometric property of spacetime, since that is the most general description that works for any test particle, and any observer, and does not require any extra concepts.

Edited by Markus Hanke

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12 hours ago, Markus Hanke said:

The point I am trying to make is that it is best to look at gravity as a geometric property of spacetime, since that is the most general description that works for any test particle, and any observer, and does not require any extra concepts.

Your mathematics is beyond me, unfortunately. Intuition alone may not be enough. But...perhaps the concept of a Gravitational Dipole is not inconsistent with what you have explained. The concept of White Holes is mentioned in Wiki and used in astronomy. It is postulated as the back of a Black Hole absorbing nothing, but only emitting the Black Hole food.

https://en.wikipedia.org/wiki/White_hole

Others are entertaining the concept of White Holes on a subatomic level. I have personally entertained the concept as this: mass density reaches a maximum at the singularity where time stops and space has collapsed and is discontinued. The food must be maintained to make this singularity continue to exist so that when the equilibrium of hydrogen drawn into the galactic corona and the mass vanishing into the black hole is reversed due to the draining of surrounding intergalactic space, the singularity eventually cannot be maintained, the [fossil] galaxy becomes a swarm of very old stars, and drifts toward areas where minimal density has begun the accumulation of a typically giant  elliptical galaxy to become one of the typical thousands of globular clusters needed to begin the more rapid star formation in the growing mass of pure hydrogen, while huge red giants are forming to do the same.

My question is, anti-hydrogen has protons and electrons with opposite charges. If these electrons produce a force akin to magnetism but due to General Relativistic considerations (electrons as actual particles moving in circular motion = acceleration toward the nuclear proton) then this force will be in opposite directions for matter and antimatter hydrogen, and gravitational fields will cause these two species to move opposite directions. In this way we would have both Black Holes and White Holes, a Gravitational Dipole. This particular dipole however would be  one where like attracts like and unlike repels unlike. It would explain an accelerating universal expansion, while maintaining a status quo in a finite Universe. It would also solve the anomalies currently covered by:

1. Dark matter;

2. Dark energy;

3. Assymetric matter-antimatter reactions.

Of particular interest is the fact that there must also be an anti-photon that displays the properties of matter and our photons symmetrically. There is a particle that fits the job description, on and of, since it was postulated to cover beta-ray energies.

Is such a situation mathematically feasible, or is this scenario contradictory to what may be so determined?

If this is a possibility, we have a Universe that was once created to continue indefinitely (ancient Egyptian idea in Book 2 of "The Divine Pymander" of Hermes). Else the Universe has always existed as is and will always continue to do so.

I must leave this to more accomplished mathematicians to evaluate as possible or impossible.

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No.
Markus will explain that gravity is not due to magnetism, or motions of opposite charges, or even mass.
It is due to energy and momentum, that space-time experiences the curvature that is gravity.

Particle and anti-particle pairs are created from the same energy, and annihilate, releasing the same energy.
Energy which causes the same curvature and geometry of space-time which the particles and photons follow.
Why would you think particles and anti-particles move differently in a gravitational potential ?

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5 hours ago, MigL said:

No.
Markus will explain that gravity is not due to magnetism, or motions of opposite charges, or even mass.
It is due to energy and momentum, that space-time experiences the curvature that is gravity.

Particle and anti-particle pairs are created from the same energy, and annihilate, releasing the same energy.
Energy which causes the same curvature and geometry of space-time which the particles and photons follow.
Why would you think particles and anti-particles move differently in a gravitational potential ?

Because, as with magnetism, there is an imbalance created in the forces emanating from positive and negative particles due to space contraction so that these unbalance fluxes produce slightly different attraction or repulsion on the two species of charged particles that make up matter or antimatter. However, these charges being reversed in antimatter, this residual force manifesting as gravity will separate the atoms neutral atoms formed from the charged particles, particularly if there are no neutral material particles in existence as exhibited by the spontaneous breakdown of neutrons outside of a nucleus or part of a neutron star. There are no stable neutral particles in a free state except for energy quanta. Also, if neutrino's are properly the antiparticle that materialises with photons in intergalactic space (where no materials annihilate one of the pair produced), White Holes would be repelling photons which pass through antimatter unimpeded, while Black Holes would repel converted material and energy as neutrino's likewise. There are a hoard of astrological phenomena that may find explanations in this scenario (gamma ray bursts, Centaurus A, Hoag's Object, M 82 with hydrogen materialisation normal to the galactic plane, recycling of matter and energy and the accelerating expansion of the Universe, and perfect conservation if anti-mass is negative). We see the photons, but are we sure we are observing ANY phenomena due to neutrino interactions with anything other than their antiparticle the photon (energy sufficient)? Could the energy range of beta rays be because they are triggered by neutrinos from our galactic core, materialising the energy bound to relativistic nuclear electrons we had to invent mesons and short range forces to explain? Was that a long unrecognised  faulty hypothesis? Are we making subatomic physics more complex than necessary? Who knows? But science advances by speculative hypotheses which need to be tested, like all of Einstein's work once the world could no longer doubt his ideas. Frankly, it took a World War to make it happen, or remained in the crackpot category. So also is all this speculation. I don't have the resources for more than that in this lifetime. The idea came to me in 1969 when I hear of antimatter and the universal expansion, and has been evolving in my mind since.

Albert.jpg

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7 hours ago, Olorin said:

Your mathematics is beyond me, unfortunately.

You need only look at the very first equation: a=0. When you are in free fall, you experience no acceleration and thus no forces act on you - and yet you are under the influence of gravity. That’s why gravity isn’t fundamentally a force in the Newtonian sense. That’s all there is to it.

The other equations are simply different ways to write that same statement; so there’s more than one way to look at it, but ultimately it always comes back to the geometry of spacetime, which is the fundamental “object” underlying all of this.

7 hours ago, Olorin said:

My question is, anti-hydrogen has protons and electrons with opposite charges. If these electrons produce a force akin to magnetism but due to General Relativistic considerations (electrons as actual particles moving in circular motion = acceleration toward the nuclear proton) then this force will be in opposite directions for matter and antimatter hydrogen, and gravitational fields will cause these two species to move opposite directions.

No, because both matter and anti-matter have positive energy density (roughly speaking, technicalities aside for now) - so gravitationally they behave the exact same. To get repulsive gravity, you would need to create a region of negative energy density - this is called exotic matter (which isn’t the same as anti-matter), and there is no evidence that such a thing exists.

7 hours ago, Olorin said:

Of particular interest is the fact that there must also be an anti-photon that displays the properties of matter and our photons symmetrically.

No, the photon is its own anti-particle. It’s kind of difficult to explain why this is so (and must be so) in a non-mathematical way; just suffice to say here that the fact can be shown mathematically.

20 minutes ago, Olorin said:

Also, if neutrino's are properly the antiparticle that materialises with photons

They are not. Neutrinos are much more closely related to electrons than to photons, and they form their own class of particles. There are three types of neutrinos and three types of anti-neutrinos, and (as being fermions) they have no direct relationship to photons.

23 minutes ago, Olorin said:

Are we making subatomic physics more complex than necessary?

The Standard Model is in excellent agreement with experiment and observation, so unfortunately its level of complexity is necessary. 

 

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On 1/11/2021 at 1:08 PM, joigus said:

Light is not ether. In fact there is no ether, as has been proven to death. There is no lack of an appropriate term: Space-time is the accepted term. It has symmetry properties that explain a great deal of how light behaves.

On one of the forums I found a good statement about the ether. "Ether is a quantum foam of virtual particles".

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49 minutes ago, SergUpstart said:

On one of the forums I found a good statement about the ether. "Ether is a quantum foam of virtual particles".

The aether is a supposed medium that light waves propagate through.  So that statement is describing something completely different.

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