Casimir Effect experiment and implications on motion theory

  • #1
Gfellow
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Quantum mechanics has argued for years that space is not a vacuum.
Arguments attempting to brush aside quantum mechanics vacuum theory claiming, it's 'just a quantum mathematical theory' can now put to rest.
In this article, laboratory experimentation demonstrates that the Casimir Effect can convert vacuum energy into work.
Does this not have huge implications for the most basic tenets of Galilean/Newtonian/Einstinian physics? That all objects fall at the same rate in a space vacuum?
If space is an expression of pressure everywhere, then - in space - there is nowhere you can roll two balls of different mass where the larger mass does not arrive sooner than the lesser - providing you make the ramp distance long enough.
Again, the ball and feather experiment works fine - providing you don't drop them from 1000 miles above the Moon (for example.)
Galilean/Newtonian/Einstinian physics works fine at 'short' distances, but breaks down over sufficiently longer distances.
The argument that the effect is so small as to be insignificant is an ill-conceived reply when one considers that the minute discrepancy observed in the precession of Mercury was a foundational observation of the verification of Einstein's paper of Relativity published in 1916.

So doesn't the Casimir Effect demonstrate that the given density of space is irrelevant, since all space has density?
The two dropped objects of different mass anywhere in the Universe will not arrive at the same time, providing the drop is given sufficient time for measurement.
In this experiment below, watch balls of varying sizes dropped in a dense viscous liquid.
Drop the same objects in a near-vacuum ANYWHERE IN THE SPARSEST VOLUME OF SPACE, and let them fall towards a third more powerful gravitational field for thousand years, won't the heavier object will arrive first?

Thoughts? Flaw in the observation or reasoning?

Best,

Stephen Goodfellow
 
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  • #2
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Does this not have huge implications for the most basic tenets of Galilean/Newtonian/Einstinian physics? That all objects fall at the same rate in a space vacuum?
Umm, the Casimir effect has been experimentally confirmed for quite some time already (since late last century sometime). I am not sure what you are so bombastic about.

Classical physics is fine. This is really not a big deal. If you have a force on an object it won’t fall the same as an object in free fall.

Frankly, if you are looking for small effects to blow way out of proportion, then I think two photon interactions are a much bigger deal since it means EM is non-linear so Maxwell’s equations are not the classical limit of QED at high energy.
 
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  • #3
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Drop the same objects in a near-vacuum ANYWHERE IN THE SPARSEST VOLUME OF SPACE, and let them fall towards a third more powerful gravitational field for thousand years, won't the heavier object will arrive first?

Huh? You have identical objects with different masses?
 
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  • #4
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The force from the Casimir effect decreases quickly with distance. More space between the objects leads to a much smaller force. The force on a ball 1 meter above the surface is of the order of 10-30 N, or ~30 orders of magnitude weaker than the gravitational force. It's utterly negligible. At 1000 km that force drops to 10-54 N.
Quantum mechanics has argued for years that space is not a vacuum.
Some parts of space are a really good approximation to a vacuum, some parts of space are not. This has nothing to do with quantum mechanics.
Does this not have huge implications for the most basic tenets of Galilean/Newtonian/Einstinian physics?
No. The Casimir effect is a result of electromagnetism. Gravity never included electromagnetism, it's not surprising that you can get different results if you add more interactions. If you hold an object in your hand it doesn't fall down because you hold it up. That doesn't make relativity wrong.
Galilean/Newtonian/Einstinian physics works fine at 'short' distances, but breaks down over sufficiently longer distances.
It's the opposite, they get better for large distances because other forces tend to drop faster.
So doesn't the Casimir Effect demonstrate that the given density of space is irrelevant, since all space has density?
That question makes no sense.

Einstein, by the way, there is no "Einstin".
 
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  • #6
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Huh? You have identical objects with different masses?
Their is an anomaly about this thing in HC Verma's book and other physics books.
HC Verma says that two objects are identical if their physical appearance is exactly same and some other books says that two objects are identical if all the things of the two objects are identical.
 
  • #7
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No matter what some Indian textbook might claim, I maintain that talking about the heavier of two identical objects is nonsense.
 
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  • #8
Gfellow
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It is not a localized Casimir Effect that is important; it is that, according to quantum mechanics, all space - no matter how hard a vacuum is - it is not empty. So no matter how inconsequential it may seem to some, all objects falling towards a strong gravitational field do so depending on their mass, and can be observed to do so providing the length of time is available for it to can be observed.
It boils down to this; can space be truly empty or not?
Quantum vacuum mechanics and the Casimir effect suggests space is not empty, anywhere.
To believe hard vacuum is truly empty demands an alternative explanation. Please let me know if such an explanation exists and could they quote the source?
 
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  • #10
Gfellow
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OK, let's forget virtual particles (I don't believe I mentioned them.)
Doesn't every cubic centimeter of deep intergalactic space have at the very least, background radiation passing through it?
If one was to perform the Casimir experiment in this sparse volume, would it not echo the same result as it does in a laboratory?
 
  • #11
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The universe is far from being a vacuum. As you say yourself, there's the micrwave background, i.e., there's a lot of thermal radiation there.

In QFT the vacuum is the ground state. By constructions it's indeed void. There's really nothing, and it's Poincare invariant.

The Casimir effect is about the quantum fluctuations of the electromagnetic field in presence of charges. The usually demonstrated textbook example usually discussed in the first few lessons on intrdocutory field theory argues with two (infinite) uncharged metallic parallel plates, and the calculation compares the "zero-point energies" of the quantized electromagnetic field at presence of the plates with the situation with no plates present. It's a nice mathematical exercise, including a simple but non-trivial case of renormalization of infinite results.

When looking a bit more careful at this treatment, one sees that employing the boundary conditions for infinitely well conducting plates from classical electrodynamics to evaluate the field modes, is already an idealization. The approximation does not lead to a bad result per se, but it is falsely used to argue that there is a zero-point energy though it's arbitrary, because in special relativity as in Newtonian physics there's no way to establish an absolute value for the total energy of a closed system; you can always add arbitrary constants to the total energy without changing any physics; only energy differences are observable. In this idealized treatment of the Casimir effect indeed such an energy difference modulo an arbitrary constant for renormalization is discussed, and using this energy difference as a function of the distance of the plate as a potential energy to evaluate the force between the plates makes physical sense.

What's really behind it on a more microscopic level is however the fluctations of the electromagnetic field due to the presence of the charges in the overall electrically neutral plates, which leads to a polarization due to the induced electromagnetic interaction between them. That's more in line with the original papers by Casimir on the polarization effects for (electrically neutral) molecules and the "residual forces" due to polarization of the molecule at the presence of another molecule.

The calculation with the plates using the macroscopic boundary conditions for the evaluation of the em. field modes in fact is the limit where the electron charge is taken to infinity. For details, see the famous paper

R. L. Jaffe, The Casimir effect and the quantum vacuum,
Phys. Rev. D 72, 021301 (2005),
https://doi.org/10.1103/PhysRevD.72.021301.
https://arxiv.org/abs/hep-th/0503158
 
  • #12
russ_watters
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@Gfellow you didn't answer @weirdoguy 's question about the definition of "vacuum". Answering that question and applying the answer to your logic will highlight the clear logical flaw in your understanding. I'll move on to that logic:
1. Many laws of physics/motion only apply in a vacuum (without augmentation).
2. There are no full/hard vacuums in the universe.
3. Since space isn't a vacuum, the laws of physics don't work.
4. The laws of physics are wrong.

I added a hint/caveat in #1 that I omitted in #3 to follow your logic. The flaw in your logic is clear, isn't it? You're forcing a constraint on the laws of physics that isn't appropriate. The laws of physics/physicists don't claim that space is a vacuum or that the laws of physics can be applied without augmentation where necessary to account for those properties.

Your objection is logically the same as claiming that Newton's laws of motion/gravity are wrong because when we drop objects in Earth's atmosphere the models don't work without augmentation to account for drag.
 
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  • #13
Gfellow
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The universe is far from being a vacuum. As you say yourself, there's the micrwave background, i.e., there's a lot of thermal radiation there.

In QFT the vacuum is the ground state. By constructions it's indeed void. There's really nothing, and it's Poincare invariant.

The Casimir effect is about the quantum fluctuations of the electromagnetic field in presence of charges. The usually demonstrated textbook example usually discussed in the first few lessons on intrdocutory field theory argues with two (infinite) uncharged metallic parallel plates, and the calculation compares the "zero-point energies" of the quantized electromagnetic field at presence of the plates with the situation with no plates present. It's a nice mathematical exercise, including a simple but non-trivial case of renormalization of infinite results.

The pulling of plates together in the Casimir Experiment. Is that not an example of work performed? Would the experiment be any different if performed in intergalactic space?
Doesn't that suggest the a hard vacuum is something rather than nothing?
That, if it is something, it would set parameters, like the velocity of light for example?
I am finding it hard to convince myself that space - even space that is ALMOST a vacuum - as being something that IS a vacuum.
Has an absolute vacuum ever been observed?

When looking a bit more careful at this treatment, one sees that employing the boundary conditions for infinitely well conducting plates from classical electrodynamics to evaluate the field modes, is already an idealization. The approximation does not lead to a bad result per se, but it is falsely used to argue that there is a zero-point energy though it's arbitrary, because in special relativity as in Newtonian physics there's no way to establish an absolute value for the total energy of a closed system; you can always add arbitrary constants to the total energy without changing any physics; only energy differences are observable. In this idealized treatment of the Casimir effect indeed such an energy difference modulo an arbitrary constant for renormalization is discussed, and using this energy difference as a function of the distance of the plate as a potential energy to evaluate the force between the plates makes physical sense.


Does this suggest that the pulling of the plates together in a hard vacuum can thus be nullified as actual observation?

What's really behind it on a more microscopic level is however the fluctations of the electromagnetic field due to the presence of the charges in the overall electrically neutral plates, which leads to a polarization due to the induced electromagnetic interaction between them. That's more in line with the original papers by Casimir on the polarization effects for (electrically neutral) molecules and the "residual forces" due to polarization of the molecule at the presence of another molecule.

So it is the property of the plates in a hard vacuum that are the cause if interference, and the vacuum is not responsible?

The calculation with the plates using the macroscopic boundary conditions for the evaluation of the em. field modes in fact is the limit where the electron charge is taken to infinity. For details, see the famous paper

Does this suggest that the EM fields in a vacuum are nothing? But shouldn't the EM fields be considered something?

R. L. Jaffe, The Casimir effect and the quantum vacuum,
Phys. Rev. D 72, 021301 (2005),
https://doi.org/10.1103/PhysRevD.72.021301.
https://arxiv.org/abs/hep-th/0503158

Is there something more recent than 2005? The paper I refer to is from 2020

Best,

Stephen Goodfellow
 
  • #14
Gfellow
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Define please what is a vacuum and if space is not empty then tell us what it is filled with. And if you want to bring up virtual particles, please read these insights first:
https://www.physicsforums.com/insights/physics-virtual-particles/
https://www.physicsforums.com/insights/misconceptions-virtual-particles/
My question is rather basic, and does not necessarily pertain to any particular property, be it virtual particles, vacuum foam or background radiation passing through a given quantity of space. What I want to know: Do absolute vacuums exist?
 
  • #15
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What I want to know: Do absolute vacuums exist?
Simple(istic) answer: No.

Now what.
 
  • #16
Gfellow
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@Gfellow you didn't answer @weirdoguy 's question about the definition of "vacuum". Answering that question and applying the answer to your logic will highlight the clear logical flaw in your understanding. I'll move on to that logic:
1. Many laws of physics/motion only apply in a vacuum (without augmentation).
2. There are no full/hard vacuums in the universe.

So my question is, if there is no such thing as a true vacuum in space, doesn't space interfere with the motion of two bodies of of different mass attracted to a powerful gravitational force, observationally measurable if allowed given the limitations of time and distance?


3. Since space isn't a vacuum, the laws of physics don't work.
4. The laws of physics are wrong.

I added a hint/caveat in #1 that I omitted in #3 to follow your logic. The flaw in your logic is clear, isn't it? You're forcing a constraint on the laws of physics that isn't appropriate. The laws of physics/physicists don't claim that space is a vacuum or that the laws of physics can be applied without augmentation where necessary to account for those properties.

Your objection is logically the same as claiming that Newton's laws of motion/gravity are wrong because when we drop objects in Earth's atmosphere the models don't work without augmentation to account for drag.


What I am suggesting is that the drag is everywhere in the Universe, (In Earth's atmosphere of otherwise) because the rarest vacuum in space is not nothing, (think the heliosphere bow shockwave,) therefore the drag is everywhere; the effect might be small, but it's there. And in consequence, the notion that objects of mass fall at the same speed towards an observably more powerful gravitational source is a useful approximation, but it is not correct.
 
  • #17
A.T.
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... a useful approximation...
Or rather an idealization, as all of physics is.
 
  • #18
Gfellow
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Umm, the Casimir effect has been experimentally confirmed for quite some time already (since late last century sometime). I am not sure what you are so bombastic about.

Confirmed to generate work? Then the 2020 paper must be no big deal.

Classical physics is fine. This is really not a big deal. If you have a force on an object it won’t fall the same as an object in free fall.

And if all space, including hard vacuum in the Universe follows suit, then the notion that balls and feathers fall at the same rate can be observed not to be true. Given sufficient time of travel for observation, the greater mass of the ball arrives first, dropping towards a gravitational pull of sufficient force.
So the present notion that all masses fall at the same rate is a useful proximation, but not the true picture.

Frankly, if you are looking for small effects to blow way out of proportion, then I think two photon interactions are a much bigger deal since it means EM is non-linear so Maxwell’s equations are not the classical limit of QED at high energy.

The the slight deviation in the precession of Mercury was a small deal, but it did change the way we thought of the Universe.
 
  • #19
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So my question is, if there is no such thing as a true vacuum in space, doesn't space interfere with the motion of two bodies of of different mass attracted to a powerful gravitational force, observationally measurable if allowed given the limitations of time and distance?
Yes, but it is not observationally measurable as far as I know.
What I am suggesting is that the drag is everywhere in the Universe, (In Earth's atmosphere of otherwise) because the rarest vacuum in space is not nothing, (think the heliosphere bow shockwave,) therefore the drag is everywhere; the effect might be small, but it's there.
Yes, that's fine.
And in consequence, the notion that objects of mass fall at the same speed towards an observably more powerful gravitational source is a useful approximation, but it is not correct.
The difference between an "approximation" and an idealization (as @A.T. said) is really important here. Yes, an approximation is not actually correct. An idealization is.
 
  • #20
Gfellow
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Simple(istic) answer: No.

Now what.
Now the ball and feather, given enough time to be observed, will not fall at the same rate anywhere in the Universe. Masses of different weight falling at the same speed towards a strong gravitational field is a useful rule-of-the-thumb approximation, but as a law it is incorrect.
 
  • #21
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Yes, but it is not observationally measurable as far as I know.

Yes, that's fine.

The difference between an "approximation" and an idealization (as @A.T. said) is really important here. Yes, an approximation is not actually correct. An idealization is.

By that logic, Einstein should have ignored the tiny discrepancy of Mercury's precession?
 
  • #22
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By that logic, Einstein should have ignored the tiny discrepancy of Mercury's precession?
No. I can't imagine what would make you think that's implied by my answer.
[edit]
Your response is at least two levels of wrong. The first we already discussed and the second level is that Newton's law of Gravity is, in fact, wrong (as Newton originally conceived its boundaries).
 
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  • #23
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The pulling of plates together in the Casimir Experiment. Is that not an example of work performed?

Sure. So what? There is nothing more mysterious here than there is with work performed in stretching a spring.
 
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  • #24
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the notion that balls and feathers fall at the same rate can be observed not to be true
And you think that is part of the foundations of classical mechanics? I am not sure what gave you that mistaken notion.

The the slight deviation in the precession of Mercury was a small deal, but it did change the way we thought of the Universe.
1601422431992.png

Just because the Casimir effect and the anomalous precession of Mercury are both small doesn't mean that they both change the way we think about the universe.

The precession of Mercury was view-changing because the then extant theories didn't account for it. Current theories not only account for the Casimir effect, but actually predict it. So the Casimir effect does not change the way we think of the universe at all, but actually the opposite: it confirms the way we think of it.

Your analogy is absurdly bad.
 
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  • #25
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No. I can't imagine what would make you think that's implied by my answer.
[edit]
Your response is at least two levels of wrong. The first we already discussed and the second level is that Newton's law of Gravity is, in fact, wrong (as Newton originally conceived its boundaries).
Galileo, Newton and Einstein were working with incomplete data, and it is truly amazing what they accomplished in spite of that.
When it came to two different weight masses, they all proceeded - as done today - on the assumption that these masses fell at the same fall-rate towards the Earth. They don't, because there is no such thing as a perfect vacuum in the Universe, so the oft used ball and feather falling in a 'vacuum' is to date an incomplete experiment. Good enough for approximation, but does not stand up to the rigor more precise experimentation.
Off the top of my head, something like, drop two balls of different mass from a distance from the Moon at a point where the balls are within the Moon's gravitational capture. See if they arrive together.
I suppose it might be possible that a less spectacular experiment could be performed in a lab.
 
  • #26
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What is this thread about? It's all over the place.
 
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  • #27
Gfellow
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And you think that is part of the foundations of classical mechanics? I am not sure what gave you that mistaken notion.


View attachment 270207
Just because the Casimir effect and the anomalous precession of Mercury are both small doesn't mean that they both change the way we think about the universe.

The precession of Mercury was view-changing because the then extant theories didn't account for it. Current theories not only account for the Casimir effect, but actually predict it. So the Casimir effect does not change the way we think of the universe at all, but actually the opposite: it confirms the way we think of it.

So how should one think of of a universe where every inch of it is something rather than nothing?
Are falling balls magically maintained by a Universe that does not consist of absolute vacuum? Where there is always inertia - no matter how small - working on the two balls falling towards a gravitational field?


Your mime! how absolutely delightful! Here's one of mine that I did myself
time gentlemen please.jpg

"Time Gentlemen, please"
 
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  • #28
russ_watters
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Galileo, Newton and Einstein were working with incomplete data, and it is truly amazing what they accomplished in spite of that.
When it came to two different weight masses, they all proceeded - as done today - on the assumption that these masses fell at the same fall-rate towards the Earth. They don't, because there is no such thing as a perfect vacuum in the Universe, so the oft used ball and feather falling in a 'vacuum' is to date an incomplete experiment. Good enough for approximation, but does not stand up to the rigor more precise experimentation.
Off the top of my head, something like, drop two balls of different mass from a distance from the Moon at a point where the balls are within the Moon's gravitational capture. See if they arrive together.
I suppose it might be possible that a less spectacular experiment could be performed in a lab.
All of that is fine, but it doesn't really address the problem with your logic. And such an experiment just isn't needed; other tests of gravity already done are far more accurate than such an experiment could be (and cheaper!).
Are falling balls magically maintained by a Universe that does not consist of absolute vacuum?
I can't imagine why you would invoke magic when all the effects being discussed here are known.

Has this thread left the rails? Have you forgotten what your original point was? Or did you recognize the flaw and move onto something else? It's hard to tell.
 
  • #29
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So how should one think of of a universe where every inch of it is something rather than nothing?
One should think of it as an extremely interesting universe!

Are falling balls magically maintained by a Universe that does not consist of absolute vacuum? Where there is always inertia - no matter how small - working on the two balls falling towards a gravitational field?
What are you talking about? Who ever thought that the universe consisted of absolute vacuum? Whose falling balls are magically maintained doing what? Since when does inertia do work?

Your mime! how absolutely delightful! Here's one of mine that I did myself
I think that you mean "meme", not "mime".
 
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  • #30
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I think that you mean "meme", not "mime".

Can you do "mentoring against the wind"?
 
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  • #31
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Would the experiment be any different if performed in intergalactic space?
No. The Casimir effect is about what happens when two conducting plates are placed close to one another, it doesn’t matter where the plates are.
 
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  • #32
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When it came to two different weight masses, they all proceeded - as done today - on the assumption that these masses fell at the same fall-rate towards the Earth.
In the absence of other forces.

See my example of holding an object in your hand. It not only falls at a different rate: It doesn't fall down at all!
Following your arguments this must certainly shake the foundations of gravity! It does not, because another force is involved.
 
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  • #33
Gfellow
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In the absence of other forces.

See my example of holding an object in your hand. It not only falls at a different rate: It doesn't fall down at all!
Following your arguments this must certainly shake the foundations of gravity! It does not, because another force is involved.
Sort of like, Galileo not letting go of the balls? A powerful argument.
 
  • #34
Gfellow
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Summary:: Does the Casimir Effect experiment debunk Galilean/Newtonian/Einstinian physics of motion?

Quantum mechanics has argued for years that space is not a vacuum.
Arguments attempting to brush aside quantum mechanics vacuum theory claiming, it's 'just a quantum mathematical theory' can now put to rest.
In this article, laboratory experimentation demonstrates that the Casimir Effect can convert vacuum energy into work.
Does this not have huge implications for the most basic tenets of Galilean/Newtonian/Einstinian physics? That all objects fall at the same rate in a space vacuum?
If space is an expression of pressure everywhere, then - in space - there is nowhere you can roll two balls of different mass where the larger mass does not arrive sooner than the lesser - providing you make the ramp distance long enough.
Again, the ball and feather experiment works fine - providing you don't drop them from 1000 miles above the Moon (for example.)
Galilean/Newtonian/Einstinian physics works fine at 'short' distances, but breaks down over sufficiently longer distances.
The argument that the effect is so small as to be insignificant is an ill-conceived reply when one considers that the minute discrepancy observed in the precession of Mercury was a foundational observation of the verification of Einstein's paper of Relativity published in 1916.

So doesn't the Casimir Effect demonstrate that the given density of space is irrelevant, since all space has density?
The two dropped objects of different mass anywhere in the Universe will not arrive at the same time, providing the drop is given sufficient time for measurement.
In this experiment below, watch balls of varying sizes dropped in a dense viscous liquid.
Drop the same objects in a near-vacuum ANYWHERE IN THE SPARSEST VOLUME OF SPACE, and let them fall towards a third more powerful gravitational field for thousand years, won't the heavier object will arrive first?

Thoughts? Flaw in the observation or reasoning?

Best,

Stephen Goodfellow

I'd like to thank everyone for their feedback; I always enjoy the active minds that inhabit this forum. Let's consider this topic closed and move on.
 
  • #35
russ_watters
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I'd like to thank everyone for their feedback; I always enjoy the active minds that inhabit this forum. Let's consider this topic closed and move on.
Youre welcome and thanks for that. I'm going to actually close this to prevent piling-on.
 

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