6 ms·

If you pressurize a sealed cavity with a gas, it's not going to move due to the internal pressure regardless of what shape you make it. If you sum all of the c

by snarfy 10y ago

If you pressurize a sealed cavity with a gas, it's not going to move due to the internal pressure regardless of what shape you make it. If you sum all of the collisions of the gas atoms along with the container, the sum momentum will be zero. Momentum is mass x velocity. Contrast this with pressure created via light. Velocities with light don't add that way. Instead there is a red/blue shift in the frequency. I can't put my finger on how this could work, but it seems there is a discontinuity here between the speed of light being constant in all reference frames and summing velocities to calculate momentum. Maybe with light, only energy conservation matters and momentum can be changed via redshift/blueshift relative to the container.

ingenter 10y ago
No, light is not different. If you want to adjust for "red/blue shift", you may use special relativity, and in special relativity you have the conservation of 4-momentum, which will give you the same result.
- snarfy 10y ago
  Ah, if my understanding is correct then this makes sense. In my initial argument I bring in relativity and the invariant speed of light. What I neglected is everything else in relativity, like lorentz transformations. I mentioned a discontinuity between invariant speed of light and summing velocities to calculate momentum. The discontinuity is distance. Velocity is distance x time, but under lorentz transformations distance is relative. The discontinuity is resolved if you include length contraction (and time dilation).
lisivka 10y ago
You know that everything around us is both matter and wave at same time (wave-particle duality). Right? I.e. small bit of matter surrounded with wave. (See any of walking droplets videos to develop intuition). Unlike regular matter, waves are propagating through space, by contraction and expanding of a field. Because of particle-wave duality, when matter is moving, EM field around matter expands and contracts at high frequency. Right? EM radiation in form of radio-waves can interact with these surrounding waves because of interference. Right? IMHO, interference between radio-waves and surrounding waves may cause effect similar to used in acoustic levitation.
- lisivka 10y ago
  These anonymous downvotes are frustrating. I cannot guess what caused them, so I cannot learn on my mistakes.
  - sbierwagen 10y ago
    I'm guessing that you were downvoted because your post doesn't make very much sense.
    - lisivka 10y ago
      Let me quote paper: «Although the idea of a pilot wave or realist interpretation of quantum mechanics is not the dominant view of physics today (which favors the Copenhagen interpretation), it has seen a strong resurgence of interest over the last decade based on some experimental work pioneered by Couder and Fort [13]. Couder and Fort discovered that bouncing a millimeter-sized droplet on a vibrating shallow fluid bath at just the right resonance frequency created a scenario where the bouncing droplet created a wave pattern on the shallow bath that also seemed to guide the droplet along its way. To Couder and Fort, this seemed very similar to the pilot-wave concept just discussed and, in subsequent testing by Couder and others, this macroscopic classical system was able to exhibit characteristics thought to be restricted to the quantum realm. To date, this hydrodynamic pilot-wave analog system has been able to duplicate the double slit experiment findings, tunneling, quantized orbits, and numerous other quantum phenomena. Bush put together two thorough review papers chronicling the experimental work being done in this domain by numerous universities [14,15].» So it makes sense in paper, but does not makes sense at HN?
      - humbledrone 10y ago
        I can't speak for anybody else who downvoted you, but I did it because your post comes across as being quite condescending. Take this pattern, for example: > You know that X. Right? > Y. Right? > Z. Right? The "You know that" part makes your argument unnecessarily personal, when your comment could just as easily be stated without any reference to the person behind the comment you were responding to. The "Right?" ending each line is also very patronizing. This sounds like how an adult might talk to a child, walking them through a line of reasoning. Maybe you did not intend to sound condescending, but you did, and this is no place for that. (Also, your post is worded as if the pilot wave theory is a fact, when it is actually not even particularly widely accepted. It is one of many interesting views of QM, but certainly not the only one.)
lutusp 10y ago
> If you pressurize a sealed cavity with a gas, it's not going to move due to the internal pressure regardless of what shape you make it. That's true of the container as a whole, but if you put a delicate torsion balance inside the container, you could see many kinds of apparent anomalies caused by circulating gases at different temperatures. At sufficiently high sensitivity even a vacuum vessel would show some anomalies arising in ordinary physics that would need to be taken into account.
pdonis 10y ago
> Momentum is mass x velocity. Only for objects with nonzero rest mass traveling at speeds much slower than the speed of light. Which obviously doesn't apply to light itself. When you are talking about light (or about massive particles like electrons traveling at speeds close to the speed of light), you have to use the correct relativistic equations. When you do that, you find that energy and momentum are conserved for light just like anything else. > Maybe with light, only energy conservation matters and momentum can be changed via redshift/blueshift relative to the container. Not according to our best current theories, no. See above.

by snarfy 10y ago

ingenter 10y ago

No, light is not different. If you want to adjust for "red/blue shift", you may use special relativity, and in special relativity you have the conservation of 4-momentum, which will give you the same result.

snarfy 10y ago
Ah, if my understanding is correct then this makes sense. In my initial argument I bring in relativity and the invariant speed of light. What I neglected is everything else in relativity, like lorentz transformations. I mentioned a discontinuity between invariant speed of light and summing velocities to calculate momentum. The discontinuity is distance. Velocity is distance x time, but under lorentz transformations distance is relative. The discontinuity is resolved if you include length contraction (and time dilation).

lisivka 10y ago

You know that everything around us is both matter and wave at same time (wave-particle duality). Right? I.e. small bit of matter surrounded with wave. (See any of walking droplets videos to develop intuition). Unlike regular matter, waves are propagating through space, by contraction and expanding of a field. Because of particle-wave duality, when matter is moving, EM field around matter expands and contracts at high frequency. Right? EM radiation in form of radio-waves can interact with these surrounding waves because of interference. Right? IMHO, interference between radio-waves and surrounding waves may cause effect similar to used in acoustic levitation.

lisivka 10y ago
These anonymous downvotes are frustrating. I cannot guess what caused them, so I cannot learn on my mistakes.
- sbierwagen 10y ago
  I'm guessing that you were downvoted because your post doesn't make very much sense.
  - lisivka 10y ago
    Let me quote paper: «Although the idea of a pilot wave or realist interpretation of quantum mechanics is not the dominant view of physics today (which favors the Copenhagen interpretation), it has seen a strong resurgence of interest over the last decade based on some experimental work pioneered by Couder and Fort [13]. Couder and Fort discovered that bouncing a millimeter-sized droplet on a vibrating shallow fluid bath at just the right resonance frequency created a scenario where the bouncing droplet created a wave pattern on the shallow bath that also seemed to guide the droplet along its way. To Couder and Fort, this seemed very similar to the pilot-wave concept just discussed and, in subsequent testing by Couder and others, this macroscopic classical system was able to exhibit characteristics thought to be restricted to the quantum realm. To date, this hydrodynamic pilot-wave analog system has been able to duplicate the double slit experiment findings, tunneling, quantized orbits, and numerous other quantum phenomena. Bush put together two thorough review papers chronicling the experimental work being done in this domain by numerous universities [14,15].» So it makes sense in paper, but does not makes sense at HN?
    - humbledrone 10y ago
      I can't speak for anybody else who downvoted you, but I did it because your post comes across as being quite condescending. Take this pattern, for example: > You know that X. Right? > Y. Right? > Z. Right? The "You know that" part makes your argument unnecessarily personal, when your comment could just as easily be stated without any reference to the person behind the comment you were responding to. The "Right?" ending each line is also very patronizing. This sounds like how an adult might talk to a child, walking them through a line of reasoning. Maybe you did not intend to sound condescending, but you did, and this is no place for that. (Also, your post is worded as if the pilot wave theory is a fact, when it is actually not even particularly widely accepted. It is one of many interesting views of QM, but certainly not the only one.)

lutusp 10y ago

> If you pressurize a sealed cavity with a gas, it's not going to move due to the internal pressure regardless of what shape you make it. That's true of the container as a whole, but if you put a delicate torsion balance inside the container, you could see many kinds of apparent anomalies caused by circulating gases at different temperatures. At sufficiently high sensitivity even a vacuum vessel would show some anomalies arising in ordinary physics that would need to be taken into account.

pdonis 10y ago

> Momentum is mass x velocity. Only for objects with nonzero rest mass traveling at speeds much slower than the speed of light. Which obviously doesn't apply to light itself. When you are talking about light (or about massive particles like electrons traveling at speeds close to the speed of light), you have to use the correct relativistic equations. When you do that, you find that energy and momentum are conserved for light just like anything else. > Maybe with light, only energy conservation matters and momentum can be changed via redshift/blueshift relative to the container. Not according to our best current theories, no. See above.