Quote from: Rodal on 05/02/2015 06:22 pmQuote from: sanman on 05/02/2015 03:22 pmQuote from: Rodal on 05/02/2015 02:00 pmIn any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.htmlGreg Egan is just showing the standing wave solution to Maxwell's equation for a truncated cone for mode shapes that have constant field in the transverse, azimuthal direction. The solutions shown by Egan are known since the 1930's. That Maxwell's equations and special relativity satisfy conservation of momentum is known in general, for any problem, for any geometrical shape. Thus, Egan is just "debunking" attempts (as done by Roger Shawyer for example or by Prof. Yang in China) trying to justify EM Drive space propulsion just using Maxwell's equations and special relativity. Egan's paper does not and cannot debunk Dr. White's conjecture for example, or Prof. Woodward's conjecture. Dr. White's conjecture can be objected on the grounds that it implies a mutable and degradable quantum vacuum, for example, but not solely on the grounds discussed by Egan.Right. A lot of the handy-wavy "theoretical" justification isn't even falsifiable. Someone just makes up some other theoretical nonsense.And the computer simulations are worse. They are based on Maxwell's Equations which literally don't allow something like the EM-drive as they conserve both momentum and energy perfectly. If you get a different result, it's either because you modified the equations that you're solving or you're just seeing an artifact of the computation.So the theoretical work can be safely ignored.
Quote from: sanman on 05/02/2015 03:22 pmQuote from: Rodal on 05/02/2015 02:00 pmIn any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.htmlGreg Egan is just showing the standing wave solution to Maxwell's equation for a truncated cone for mode shapes that have constant field in the transverse, azimuthal direction. The solutions shown by Egan are known since the 1930's. That Maxwell's equations and special relativity satisfy conservation of momentum is known in general, for any problem, for any geometrical shape. Thus, Egan is just "debunking" attempts (as done by Roger Shawyer for example or by Prof. Yang in China) trying to justify EM Drive space propulsion just using Maxwell's equations and special relativity. Egan's paper does not and cannot debunk Dr. White's conjecture for example, or Prof. Woodward's conjecture. Dr. White's conjecture can be objected on the grounds that it implies a mutable and degradable quantum vacuum, for example, but not solely on the grounds discussed by Egan.
Quote from: Rodal on 05/02/2015 02:00 pmIn any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect Alright, so the standing wave loses energy in an amount that offsets the kinetic energy gain associated with acceleration - and this is supposed to satisfy conservation of energy. And conservation of momentum is satisfied by using energy-mass equivalency?I was just wondering what the mechanism is by which pumping up the standing wave then creates a net force on the cavity.Here's a debunking by Greg Egan, showing why you can't have net force just because the cavity happens to be asymmetric:http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Simple.html
In any case, whatever effect one can conjecture, the challenge is not only to prove the existence of the effect but just as important, to demonstrate conservation of momentum for a cavity accelerated under such an effect
m_b1 = m_b2 = 4 kg mass of each bowling ballm_r = 8 kg mass of rocketv_r = 0 m/s velocity of rocketv_b1 = 0 m/s velocity of bowling ball 1v_b2 = 0 m/s velocity of bowling ball 2
v_r' = ? velocity of rocket after first bowling ball launchedv_b1' = ? velocity of first bowling ball after launchv_b2' = ? velocity of second bowling ball after launch of first
Thus as the velocity of the waveguide increases in the direction of thrust, the thrust will decrease until a limiting velocity is reached when T=0.
What kind of damage would a special, or preferred frame of reference do to our understanding of the cosmos?
And now we have a pretty good video, objective (even including Sean Carroll from CalTech, and Alcubierre stating that he thinks his warp-drive concept is not practically feasible for centuries) about the NSF article on the EM Drive !http://www.newsy.com/47123/ There is some hope for the media, as these guys got this "right", fair and balanced, respecting science and yet keeping up some hope and they put the video together in a short amount of time
In order for White's proposed explanation to make any sense at all, you need to assume 3 things:(1) momentum can be stored and propagated through virtual particle pairs that are created in the vacuum fluctuations of free space. Call this the QVP. Obviously this is White's controversial claim, but let's entertain the idea.(2) storing momentum int the QVP must be "difficult". If it were easy, then momentum would be lost into the QVP all the time, from all different types of interactions, and we wouldn't observe conservation of momentum in general. For some reason, we must accept that the situation of standing waves in a specially shaped resonant cavity is a special situation that does enable momentum transfer into the QVP.
Quote from: vide on 05/03/2015 04:14 pmI'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?Those are all the force plots I'm aware of concerning the frustum test article at EagleworksSource file name or figure in 2014 Brady report :1/ Page 15, Fig 19 top2/ Page 15, Fig 19 middle3/ Page 15, Fig 19 bottom4/ Page 17, Fig 21 top5/ Page 17, Fig 21 bottom6/ Page 18, Fig 22 Eagleworks Lab Conical Resonant Cavity Test Article Data-1, TE012 Mode_03-06-2014.jpg7/ July 01, 2014 Copper Frustum PTFE_901.93MHz TM010 Thrust Signal in-Air.jpg8/ March 2015 Copper Frustum 1,937.15MHz_50W_Forward_in-Air_Foam-Board Encl_Data Run.jpg9/ Frustrum 2 energy and pressure Plus Lab Data_Polycarbonate-1_May 07, 2014.jpg10/ Copper Kettle Data-Runs_TM212_12-12-2014A_5x10-6 Torr_50W.jpg11/ Jan 16 2015_ Copper Frustum 1,937.188MHz in-5x10-4 Torr_35W_Reversed_Data Run-1B.jpgOf those only the last 2 are results in vacuumThere is also 12/ Jan 2015 Copper Frustum 1,937.15MHz in-Air_50W_Forward & Reversed_Data Runs.jpgbut I'm unsure the forward data is different from one of the previous forward plots
I'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?
The NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China
From another thread on this forum:Quote from: frobnicat on 05/03/2015 04:53 pmQuote from: vide on 05/03/2015 04:14 pmI'm sorry if this question is covered somewhere else, but is there a list of recent force plots that were posted on this forum?Those are all the force plots I'm aware of concerning the frustum test article at EagleworksSource file name or figure in 2014 Brady report :1/ Page 15, Fig 19 top2/ Page 15, Fig 19 middle3/ Page 15, Fig 19 bottom4/ Page 17, Fig 21 top5/ Page 17, Fig 21 bottom6/ Page 18, Fig 22 Eagleworks Lab Conical Resonant Cavity Test Article Data-1, TE012 Mode_03-06-2014.jpg7/ July 01, 2014 Copper Frustum PTFE_901.93MHz TM010 Thrust Signal in-Air.jpg8/ March 2015 Copper Frustum 1,937.15MHz_50W_Forward_in-Air_Foam-Board Encl_Data Run.jpg9/ Frustrum 2 energy and pressure Plus Lab Data_Polycarbonate-1_May 07, 2014.jpg10/ Copper Kettle Data-Runs_TM212_12-12-2014A_5x10-6 Torr_50W.jpg11/ Jan 16 2015_ Copper Frustum 1,937.188MHz in-5x10-4 Torr_35W_Reversed_Data Run-1B.jpgOf those only the last 2 are results in vacuumThere is also 12/ Jan 2015 Copper Frustum 1,937.15MHz in-Air_50W_Forward & Reversed_Data Runs.jpgbut I'm unsure the forward data is different from one of the previous forward plotsThank you so much. I took the liberty of uploading vacuum graphs into an album.Did the theory predict an increase in the rise/fall time constant in vacuum? If it did not, why is it not falsified by the experimental data? Does the theory predict thrust disparity in those two graphs? If it does, why is it not falsified?This paragraph seems very unclear to me.QuoteThe NASASpaceflight.com group has given consideration to whether the experimental measurements of thrust force were the result of an artifact. Despite considerable effort within the NASASpaceflight.com forum to dismiss the reported thrust as an artifact, the EM Drive results have yet to be falsified.Can someone clarify what exactly would it take for "NASASpaceflight.com forum to dismiss the reported thrust as an artifact"?QuoteAfter consistent reports of thrust measurements from EM Drive experiments in the US, UK, and ChinaIn which of the competing theories was 0.7 N at 2.5kW consistent with ~78uN at 50W (linear extrapolated 14 000 uN) ? How was this non-linear relationship (quadratic?) consistent with 54uN at 2.6W ?What is the relation between this website ("nasaspaceflight.com") and NASA?re: Star One, can you give me some examples?
Just a general comment even by the low standards of space & science reporting online it seems this particular article has suffered terribly in its wider reporting and analysis. I hope this hasn't caused any damage to the site's reputation.
What is the relation between this website ("nasaspaceflight.com") and NASA?
*snip*I would like to remind the readers of SF of James Blish's Cities in Flight where a new space drive technology was quite simple and easy to build, but that verifying and understanding the physics of it became mankind's largest Giga project. However this works out in the end, I don't think any of us have any certainty of how that will be.
This may sound off the wall, but I have an idea for low cost experiments. Use a Crooke's Radiometer positioned adjacent to the device in the thrust direction. Distance to the device, pane charge, temperature, pressure, polarization of light allowed through the radiometer wall, and mill pane materials are controls to be varied. Very low mass panes should be constructed, perhaps by coating thin slivers of aerogel through vacuum metalization or other very thin layer material application processes for the emissive and aborbant sides of the pane. Hypothesis: If any propellant is present, to include virtual particles temporarily conferred enough energy to bring them into a non-virtual state, then it should be possible to observe radiometer motion under the right combination of conditions and materials. The conditions and materials that achieve radiometer motion then provide insight into the nature of propellant.I do not have the expertise to evaluate which materials and conditions should be tried, nor in which order. Skepticism: The mass and friction of the radiometer system must be low enough that a fraction of the thrust generated by the device is sufficient to cause rotation. Experiments using materials with thermoelectric properties or other sophisticated materials may be required and may not be inexpensive. edit: To clarify, the goal in the experiments would not necessarily be to demonstrate thermal phenomena, but to adapt the operating principle of the radiometer to different interactions with the environment until the correct interaction is discovered.