What I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.
Quote from: ppnl on 04/30/2015 06:33 pmIt is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.You are assuming that conservation of energy or momentum would be violated. This is only true if the device (and its attached spaceship, if any) is a closed system, but the basis of the proposed theories of how it works is that it is NOT a closed system. Instead it is coupled to the quantum vacuum somehow, and the change in momentum of the device could be balanced by an equal but opposite change in the local momentum of the quantum vacuum, which could propagate from virtual particle to virtual particle in a wave-like manner (like a sound wave) until it is transfered to (possibly quite distant) non-virtual matter. Although by then the momentum transfer per unit mass would be so tiny that it would probably be quite undetectable.
It is not close mindedness to point out that violating conservation of energy and momentum create massive problems for the supposed effect. This is especially true when many of the proponents do not understand that the conservation laws are being violated or understand the consequences of those violations.
Taking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.
I agree, it isn't closed minded to point that out. However it is closed minded if you believe what has been accepted as a LAW of physics can never be disproven or modified.
This theory will not be disproven by logic. It will only be disproven, or proven, by scientific experimentation and examination of emperical evidence. Anyone who thinks it will be proven solely by logical argument of currently known physics IS CLOSED MINDED. You have to experiment according to scientific method protocol and then you have to FOLLOW THE EVIDENCE.
Quote from: CW on 04/30/2015 06:09 pmTaking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.The latter does not follow from the former.
Quote from: indigodarkwolf on 04/30/2015 06:57 pmWhat I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.It isn't clear to me what you are saying here.Take a car. It takes four times as much energy to accelerate from 10 mph to 20 mph as it took to accelerate from zero to ten mph. A rocket has the same problem but much worse because it takes its reaction mass with it.
(snip...)The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.*THEN* the claims will be taken by most scientists very seriously.
However, Paul March, an engineer at NASA Eagleworks, recently reported in NASASpaceFlight.com’s forum (on a thread now over 500,000 views) that NASA has successfully tested their EM Drive in a hard vacuum – the first time any organization has reported such a successful test.To this end, NASA Eagleworks has now nullified the prevailing hypothesis that thrust measurements were due to thermal convection.
Quote from: QuantumG on 04/30/2015 04:49 amQuote from: Ludus on 04/30/2015 04:38 amWhat's the cheapest EM spacecraft design that should do clearly impossible things?About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R. Heck, there's cubesats that have flown for less.This seems about right and is a major reason I'm skeptical. Lab experiments are pointless for convincing anyone. Based on everything reported it should be quite easy to put an EMdrive on a little satellite paid for by Kickstarter and get it a free ride in the trunk of a Dragon. It just has to change it's orbit in a way that according to claims should be easy for First Gen EM drive but also be impossible for any accepted technology. It should be able to keep up orbital maneuvering long after it would be impossible using any known design. This would be transparent and open to the world. Cue Nobel prize, whatever funding they want, Heinlein prize, eternal glory. What's stopping this?
Quote from: Ludus on 04/30/2015 04:38 amWhat's the cheapest EM spacecraft design that should do clearly impossible things?About $10,000. You could Kickstarter it and get it on the next Dragon flight, ala A3R. Heck, there's cubesats that have flown for less.
What's the cheapest EM spacecraft design that should do clearly impossible things?
Quote from: gospacex on 04/30/2015 08:34 pm(snip...)The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.*THEN* the claims will be taken by most scientists very seriously.From the article, it looks like NASA Eagleworks has replicated the results in a vacuum in the lab:QuoteHowever, Paul March, an engineer at NASA Eagleworks, recently reported in NASASpaceFlight.com’s forum (on a thread now over 500,000 views) that NASA has successfully tested their EM Drive in a hard vacuum – the first time any organization has reported such a successful test.To this end, NASA Eagleworks has now nullified the prevailing hypothesis that thrust measurements were due to thermal convection.
Quote from: ppnl on 04/30/2015 08:05 pmQuote from: indigodarkwolf on 04/30/2015 06:57 pmWhat I'm not following from ppnl's (and other perpetual-motion theorizers') argument is how a constant thrust, sans propellant, results in a perpetual-motion, inventing-energy-from-nowhere scheme. Surely, even with a propellant-based thruster, there exists some threshold V relative to some reference frame, wherein the loss of M from propulsion is completely dominated by the increase in V, since KE = (1/2)M*V2?Looking at KE, or dKE/dt, seems fallacious to me for that reason. Maybe I just don't understand the math well enough.It isn't clear to me what you are saying here.Take a car. It takes four times as much energy to accelerate from 10 mph to 20 mph as it took to accelerate from zero to ten mph. A rocket has the same problem but much worse because it takes its reaction mass with it.A car doesn't contain reaction mass? What about gasoline?Also, it doesn't take 4x the energy to double a car's velocity. A car has 4x the KE after doubling velocity, but that is not the same thing as saying 4x KE was required to get there.Not to mention, the energy requirements of accelerating a car include overcoming wind resistance and friction, which resists the forward motion of the car. Maintaining a velocity against these forces is a measure of work, not energy. And since the formula for the force of drag resistance also includes V2, that means that there is 4x as much drag at 20mph as there is at 10mph, and so 4x as much work is required to maintain velocity each time you double velocity. This is still not the same thing as 4x as much energy.
Quote from: gospacex on 04/30/2015 08:23 pmQuote from: CW on 04/30/2015 06:09 pmTaking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.The latter does not follow from the former.If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.
Quote from: gospacex on 04/30/2015 08:34 pm(snip...)The thing to do now is to provide extraordinary, compelling evidence. Experiment needs to be redone in a much more clean environment. Eventually, if/when tests in vacuum but on Earth seem to still show the effect, it will need to be redone in space, away from Earth magnetic field, IR radiation etc.*THEN* the claims will be taken by most scientists very seriously.From the article, it looks like NASA Eagleworks has replicated the results in a vacuum in the lab:
Quote from: CW on 04/30/2015 08:38 pmQuote from: gospacex on 04/30/2015 08:23 pmQuote from: CW on 04/30/2015 06:09 pmTaking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.The latter does not follow from the former.If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.No. There are theories in which the past has no beginning (say, cyclic Big Bang/Big Crunch models). In such theories, energy "was always there", there was no point in time when it had to be created.
Quote from: gospacex on 04/30/2015 09:32 pmQuote from: CW on 04/30/2015 08:38 pmQuote from: gospacex on 04/30/2015 08:23 pmQuote from: CW on 04/30/2015 06:09 pmTaking conservation of energy literally or dogmatically, then energy can neither be created nor destroyed, and hence should be Zero in any coordinate at any given instance in time.The latter does not follow from the former.If you want to avoid supernatural influence in shape of gods or other unphysical things that can magically pull any trick they want, it does.No. There are theories in which the past has no beginning (say, cyclic Big Bang/Big Crunch models). In such theories, energy "was always there", there was no point in time when it had to be created.What value is a theory that can never be tested? At best, it's a hypothesis. Sounds an awful lot like religion to me.
When you have eliminated the impossible, whatever remains, however improbable, must be the truth...