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#2280 by sanman on 19 Oct, 2017 15:55
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It was Sakharov who said that the mysteries of the Vacuum would be the great challenge for 21st century physics.
https://arxiv.org/pdf/hep-ph/0112031.pdf
Thank you for this paper, especially for parts 5 and 8, and although many related and unrelated concepts are showed together. The following discussion between Okun and Sakharov made me smile
Quote from: Lev Borisovich OkunThe spontaneous decay of a false vacuum starts by formation through quantum tunneling of the smallest bubble […] After that the bubble expands classically, destroying the universe. When I first thought that the creation of a bubble could be catalyzed at a collider, my back shivered. Then I reassured myself: all possible collisions have already occurred in the early universe. A few months later I told Andrei Sakharov about the bubble. His reaction was: “Such theoretical work should be forbidden”. My argument about collisions in the early universe was rejected by him: “Nobody had collided two nuclei of lead”.
Yeah, I noticed that paragraph too. LHC has been operating for awhile, and no mini-black-holes were created to swallow the Earth, as some doomsayers predicted. When stars explode or crash into each other, etc, it doesn't result in the destruction of our universe.
But rather than directly destroying a universe, I'm wondering if there's some way to leech off it? -
#2281 by flux_capacitor on 19 Oct, 2017 17:03
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Yeah, I noticed that paragraph too. LHC has been operating for awhile, and no mini-black-holes were created to swallow the Earth, as some doomsayers predicted. When stars explode or crash into each other, etc, it doesn't result in the destruction of our universe.
Yes, but although colliders reach high energies, they lack the high density states that one can find in neutron stars, not to say the Big Bang itself. So fortunately nobody recreated a black hole in a lab, even with the LHC.
But Sakharov talked about practical high density devices.
In 1951, he made various experiments with MK-2 magnetocumulative devices (an explosively pumped flux compression generator of the second type, producing pulses up to one hundred millions amperes and magnetic fields growing from an initial steady state value of 2.5 teslas to a pulse over 250 teslas, a technology unknown to the West until the publication of Sakharov's memories in English in the 1980s):
Sakharov diverted the MK-2 generator, not for the production of ultra high intensity electric currents, but as a pulsed particle accelerator, literally a "plasma gun". His device was firing a 2-gram aluminum ring at speeds over 100 km/s. Under the violent induced eddy currents flowing through the ring, the aluminum was instantly vaporized in a stable self-confined plasma toroid that was accelerated by Lorentz forces up to tremendous speeds.
However in his memories, Sakharov pointed to a stunning although possibly frightening solution. He suggested to scale this experiment using superconducting electromagnets instead of the primitive copper coils they used in the 1951 experiment, and to replace the chemical explosive by a thermonuclear one (!) and more exactly not one but two devices facing each other. Electromagnets would be vaporized due to the atomic explosion but currents would continue to flow in the nuclear plasma for enough time to focus the explosion as magnetic lenses. He said:Quote from: A. D. SakharovBy means of large pulsed magnetic lenses (the energy of the magnetic field representing the equivalent of several hundred kilotons) it is possible to focus a beam with an intensity of 1018 / 10-5 = 1023 protons/sec on a surface area of 1 mm2. It would then be possible to obtain, under good conditions of reliability, the recording of phenomena involving the collision of the beams of two accelerators, with an effective cross-section of the order of 10-30 cm2. In order to carry out such experiments, it would of course be necessary to have automatic systems (servo-controls) to compensate for the space charge and to correct the magnetic field.
Apart from the quite grandiose projects of which we have just spoken, it seems to us that MK generators can be useful in many fields of scientific research.
We do not know if this kind of experiment has been conducted in the USSR or in the USA (for example as underground nuclear tests in Nevada in the 1980s). However I cannot help but think of inverting the mass of particles, creating large quantities of antimatter, or bringing about even stranger things in spacetime.
About ten years ago I typed the whole chapter of Sakharov's Collected Scientific work in a searchable PDF, attached. Sorry this is in French but you can also buy Sakharov's book in English (copies are still available on Amazon) or translate my PDF with Google Translate. Third way: learn French.
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#2282 by RERT on 19 Oct, 2017 18:27
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Meberbs -
If you set up a metric space which simply displays nothing but variable time dilation, you will see particles move on accelerated geodesics. If you set the time dilation correctly, you can recover the geodesics of Newtonian Gravitation. The full equations of GR require space to be distorted as well, in eg the Schwarzschild metric.
This isn’t wrong at all, just looking at things from a different perspective.
If you think GR is correct, and you can engineer a spatially varying time dilation, you will expect to see accelerated particles subject to gravity-like forces. Just write out the equations in a simple case, you will see it. I think this idea is mainstream, not left field. -
#2283 by RERT on 19 Oct, 2017 18:42
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...and fwiw, in the Earth environment, the corrections of GR are infinitesimal: about 8mm in 6000km, about 1 in 10^9 if I did the sum right.
So time dilation does almost all the job... -
#2284 by meberbs on 19 Oct, 2017 19:27
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Meberbs -
Please read my previous posts and address what I said. To reiterate: Time dilation exists in situations that do not involve gravity. If time dilation caused gravity, then gravity should appear during other accelerations.
If you set up a metric space which simply displays nothing but variable time dilation, you will see particles move on accelerated geodesics. If you set the time dilation correctly, you can recover the geodesics of Newtonian Gravitation. The full equations of GR require space to be distorted as well, in eg the Schwarzschild metric.
This isn’t wrong at all, just looking at things from a different perspective.
If you think GR is correct, and you can engineer a spatially varying time dilation, you will expect to see accelerated particles subject to gravity-like forces. Just write out the equations in a simple case, you will see it. I think this idea is mainstream, not left field. -
#2285 by WarpTech on 19 Oct, 2017 23:14
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...
Even if your statement was right, you would still be contradicting RERT, because you are saying that we don't know which causes which, while he is not only stating that time dilation is the cause, but that we know how (exactly what mechanism) it causes it.
I said there is no experiment that has proven it. As far as "exactly what mechanism" causes it, I actually do know. Anyone who has read my QG paper from the Estes Park proceedings would know this too.
RERT did not define "rate of time" and it is not something I have seen a common definition for either, in fact where I have seen it is a poster here who repeatedly insists on a nonsensical theory where he claims that space is not real and only time exists. You provided a definition, but that does not retroactively make it OK for RERT to use an undefined term, or explain why the common term "time dilation" was not used.
My statements were not nitpicks, they were pointing out major factual inaccuracies, and the use of undefined terms, which in particular is necessary for understanding. Your dismissal of this as a nitpick indicates that you are the one not interested in understanding.
Maybe I'm just more in-tune with how people think, or maybe all those years I've spent on Usenet forums has given me the upper hand at deciphering meaning from non-rigorous text. I had no difficulty understanding what he meant and I felt no need to correct him. You on the other hand, did not even try to understand the meaning of what was said. You dismissed it as gibberish because it didn't fit inside your box.
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#2286 by WarpTech on 19 Oct, 2017 23:17
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Meberbs -
Please read my previous posts and address what I said. To reiterate: Time dilation exists in situations that do not involve gravity. If time dilation caused gravity, then gravity should appear during other accelerations.
If you set up a metric space which simply displays nothing but variable time dilation, you will see particles move on accelerated geodesics. If you set the time dilation correctly, you can recover the geodesics of Newtonian Gravitation. The full equations of GR require space to be distorted as well, in eg the Schwarzschild metric.
This isn’t wrong at all, just looking at things from a different perspective.
If you think GR is correct, and you can engineer a spatially varying time dilation, you will expect to see accelerated particles subject to gravity-like forces. Just write out the equations in a simple case, you will see it. I think this idea is mainstream, not left field.
Example of a case where acceleration is present and gravity is not? How could you determine that there are no gravitational effects? -
#2287 by Monomorphic on 19 Oct, 2017 23:22
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The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
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#2288 by meberbs on 20 Oct, 2017 02:20
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...
Even if your statement was right, you would still be contradicting RERT, because you are saying that we don't know which causes which, while he is not only stating that time dilation is the cause, but that we know how (exactly what mechanism) it causes it.
I said there is no experiment that has proven it. As far as "exactly what mechanism" causes it, I actually do know. Anyone who has read my QG paper from the Estes Park proceedings would know this too.
You said (emphasis mine):There is no experiment or theory that has predicted or determined which came first, gravity or time dilation. The effects are indistinguishable under all observations that I am aware of.
You are contradicting yourself completely here by now claiming that you have a theory that does something you claim that no theory does.
Also, have you revised your paper since I demonstrated for you that your understanding of one of the simplest examples of acceleration in relativity (the "twin paradox") was wrong?
So your reaction to being proven wrong on technical grounds is to make up lies about the person you are talking with?
RERT did not define "rate of time" and it is not something I have seen a common definition for either, in fact where I have seen it is a poster here who repeatedly insists on a nonsensical theory where he claims that space is not real and only time exists. You provided a definition, but that does not retroactively make it OK for RERT to use an undefined term, or explain why the common term "time dilation" was not used.
My statements were not nitpicks, they were pointing out major factual inaccuracies, and the use of undefined terms, which in particular is necessary for understanding. Your dismissal of this as a nitpick indicates that you are the one not interested in understanding.
Maybe I'm just more in-tune with how people think, or maybe all those years I've spent on Usenet forums has given me the upper hand at deciphering meaning from non-rigorous text. I had no difficulty understanding what he meant and I felt no need to correct him. You on the other hand, did not even try to understand the meaning of what was said. You dismissed it as gibberish because it didn't fit inside your box.
I said:Newtonian gravity does not have any time dilation. also, "rate of time" is not a defined physics term, so I am just assuming you mean "time dilation."
I did not dismiss it as gibberish, I specifically stated my assumption of what he meant, which is the same as what you said. I clearly not only tried to understand him, but if what you said is the correct interpretation of what he meant, then I did understand him, but unlike you I do not find it wise just to assume that I am correct about someone's meaning when they use a non-standard term.Example of a case where acceleration is present and gravity is not? How could you determine that there are no gravitational effects?
I hope this was intended as some kind of bad joke, because it is trivial to come up with examples, and if you actually read my recent posts on this thread, I already mentioned one. -
#2289 by meberbs on 20 Oct, 2017 02:22
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Feeling gravity act on us means we "are not" accelerating with in this well and resisting our inertia, while a rockets force acting on us means we "are" accelerating. What they probably have in common is the object is resisting what ever is responsible for inertia.
What they have in common is more than that. You should research the equivalence principle.
https://en.wikipedia.org/wiki/Equivalence_principle -
#2290 by JonathanD on 20 Oct, 2017 02:59
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The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
1) You are awesomely dedicated
2) If only we had access.... http://www.chicagotribune.com/lifestyles/health/sns-tns-bc-health-anechoic-chamber-20171013-story.html
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#2291 by PotomacNeuron on 20 Oct, 2017 03:35
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The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
You reminded me of an issue of our basement. We had large AC current running through our water main copper pipe. The current came from the front side of the house where the water main entered the basement, followed the water main to the back of the house, ran into heater and AC, followed the AC copper refrigerant pipe, and went out of the house into where the AC out door unit was grounded. It was present even if I shut down all power from the electric box. The current was likely running from neighbor's house grounding to the transformer grounding near the pole, and it found an easy route through my basement.
My wife worried about EM 'contamination'. I finally got rid of it by breaking the water main, inserted half a foot of hard plastic pipe (not PVC, but another safer type). The voltage across the gap is not high. I forgot the number, but it may be half a volt. What I remember was that it was much lower than pb's or cu's reduction voltage (to be safe).
I mentioned this because sometimes it is not easy to identify the noise source. Maybe it is from something that are not convection, acoustic or seismic. -
#2292 by Star-Drive on 20 Oct, 2017 04:07
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The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
Jamie:
You reminded me about how much more quiet the EW torque pendulum trace became when we pulled a vacuum on the vacuum tank and came to the conclusion that the trace noise had more to do with acoustic noise and lower frequency sonic waves impinging on the vacuum tank than anything else. You really do need to think about getting a vacuum chamber with at least a roughing pump that can bring your tank pressures below 1x10^-3 Torr for the best solution to this problem. However adding a vacuum system to your test rig would also mean you would have to vacuum proof all your equipment that would be in the vacuum environment and that can be a real pain in its own right, and that process took us over a year to master and pay for. In the meantime good luck with your acoustical shielding.
Best, Paul M. -
#2293 by Bob Woods on 20 Oct, 2017 04:22
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[quote author=Star-Drive link=topic=42978.msg1739800#msg1739800 "... In the meantime good luck with your acoustical shielding."
Best, Paul M.
Paul, Jamie is a very impressive young man. -
#2294 by RERT on 20 Oct, 2017 09:18
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Meberbs -
Here is a simple model metric to describe a spatially varying rate of flow of time/time dilation/g00:
ds˛=-c˛(1-f)dt˛+dx˛+dy˛+dz˛
Where f = f(x). Go through the algebra and the geodesic equations are:
(d˛t/dτ˛)-(∂f/∂x)(dt/dτ)(dx/dτ)/(1-f) =0
(d˛x/dτ˛)-˝c˛(∂f/∂x)(dt/dτ)˛=0
These integrate to give
dt/dτ=1/(1-f)
d˛x/dt˛=˝c˛(∂f/∂x)
The two equations in x mean that particles are accelerated, both with respect to proper time and distant observers.
It doesn't matter at all what other cases of acceleration with or without gravity exist. (Notice that time dilation that is not spatially variable is irrelevant.) I'm not discussing those. I'm discussing the above case, where it is manifest that a spatially varying g00 causes accelerations. If you can engineer that (big ask) things will start to move, according to accepted physics. -
#2295 by ThatOtherGuy on 20 Oct, 2017 10:48
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The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important.
WOW !!!
Now you'll need a webcam to see what's going on inside the test rig
As for seismic noise, are there pipes or in any case ducts running under the floor ? If so, maybe moving the rig to another position may help further reducing the noise; at any rate, since we're at acoustics, what about these ?I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
I'm not sure it incorporating the damping would work, I suspect that building an external "acoustic dampening enclosure" (some kind of box containing the rig) placed outside the rig and not touching it may work better
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#2296 by Star-Drive on 20 Oct, 2017 11:46
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[quote author=Star-Drive link=topic=42978.msg1739800#msg1739800 "... In the meantime good luck with your acoustical shielding."
Best, Paul M.
Paul, Jamie is a very impressive young man.
Bob:
Agreed. See attached picture of Jamie I took of him in front of the Eagleworks Lab's vacuum chamber when Jamie visited the lab back in January 2017. He will go far...
Best, Paul M.
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#2297 by Rodal on 20 Oct, 2017 12:30
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The blankets and insulation help remove internal convection currents, as it thermally insulates the chamber.The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
Jamie:
You reminded me about how much more quiet the EW torque pendulum trace became when we pulled a vacuum on the vacuum tank and came to the conclusion that the trace noise had more to do with acoustic noise and lower frequency sonic waves impinging on the vacuum tank than anything else. ....
It is not clear why you think the noise wasQuotemore to do with acoustic noise
(sound waves, many of which Monomorphic should be able to hear if they are within the audible range frequencies) instead of just thermal convection. Thermal convection is excited by differences in temperature between the wall surfaces (and floor and ceiling surfaces) of the test chamber: those are the thermal boundary conditions. When you insulate the surfaces, you remove a great deal of the excitation of thermal convection.
Typical thermal convection currents (imparted by natural thermal convection) should be able to impart forces that are orders of magnitude larger than the forces imparted by acoustic waves in a typical office environment. Or was Monomorphic playing very loud music during the experiments and had big woofers directed at the experiment? [in which case the solution is simply to stop playing the music] -
#2298 by Monomorphic on 20 Oct, 2017 12:47
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Was Monomorphic playing very loud music during the experiments and had big woofers directed at the experiment?
I was not playing loud music. If it is mostly convection, what are other ways to reduce it? I wonder if it would help if I filled some of the interior of the draft enclosure with foam blocks to help break up the larger volumes of air.
A vacuum chamber is probably out of the question for the time being. Not only is there a large cost with building the chamber, but as Paul pointed out, the electronics and batteries would need to be vacuum hardened or otherwise protected from the vacuum. There is vacuum rated 3D printer filament available, but the PLA I used would out-gas in a vacuum. -
#2299 by dustinthewind on 20 Oct, 2017 13:15
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The blankets and insulation help remove internal convection currents, as it thermally insulates the chamber.The noise returned the next day after removing the sorbothane pads with the same vigor as before. And after tearing down and rebuilding the torsional pendulum again that same day, the noise was still present. That is when I was reminded of PotomacNeuron saying something like, "remove the source of the noise and the experiment is good to go."
With all electronics not powered, the most likely sources of noise are convection, acoustic, and seismic. I live in a seismically stable area, far away from major roads or major sources of ground vibrations. That leaves us with convection and acoustic sources of noise. I pulled out all of my drop cloths and furniture blankets to help better insulate the draft enclosure. This seems to have done the trick. As of writing this, the pendulum has been stable for hours.
It seems at these <3uN resolution levels, convection and acoustic insulation/damping becomes most important. I plan on incorporating acoustic damping inside the enclosure as well as beefing up on the exterior layers.
Jamie:
You reminded me about how much more quiet the EW torque pendulum trace became when we pulled a vacuum on the vacuum tank and came to the conclusion that the trace noise had more to do with acoustic noise and lower frequency sonic waves impinging on the vacuum tank than anything else. ....
It is not clear why you think the noise wasQuotemore to do with acoustic noise
(sound waves, many of which Monomorphic should be able to hear if they are within the audible range frequencies) instead of just thermal convection. Thermal convection is excited by differences in temperature between the wall surfaces (and floor and ceiling surfaces) of the test chamber: those are the thermal boundary conditions. When you insulate the surfaces, you remove a great deal of the excitation of thermal convection.
Typical thermal convection currents (imparted by natural thermal convection) should be able to impart forces that are orders of magnitude larger than the forces imparted by acoustic waves in a typical office environment. Or was Monomorphic playing very loud music during the experiments and had big woofers directed at the experiment? [in which case the solution is simply to stop playing the music]
If he used just glass would that be a shield enough from convection currents allowing him to still see what is going on with his experiment? If not glass what about glass with a layer of aerogel. Not sure that is an easy thing to come by.
The aerogel-glass process T Woignier, J Phalippou - Clays and Hydrosilicate Gels in …, 1992 - books.google.com
Plexiglass?
Clear plastic stretched over, maybe saran wrap or something thicker?
There is just something a bit more satisfying about being able to look at and analyze your set up in a glance.
