spaceship drive snake oil
Dr. Slack, Tue Sept 19 2006, 01:15PMHas anybody noticed last week's New Scientist front cover article, "An end to wings and wheels"? An engineer named Shawyer is claiming that a truncated cone filled with microwave photons is givin him a reactionless force
. Not a lot at the moment, milliNewtons for a kWatt input, but any such force appears to violate conservation of momentum. There's a short write-up on Wikipedia under EmDrive, and their website goes by that name.His claim is that a proper relativistic treatment of the photons means that there is an unequal force on the ends, that is not fully compensated by the force on the sloping sides, giving a net force.
Neglecting the measurements and the detail of the theory for the moment and going for first principles, my thoughts are as follows. Relativity is a self-consistent theory, and is also consistent with the conservation of both momentum and energy. Therefore any calculation done using it should produce predictions which are also consistent, it is not logically possible to produce a contradictory answer (like doing addition with integers, it can only produce only integers and not fractions). If they are not consistent with the conservation laws, it indicates that there is an error in the maths. Or he is using something other than relativity to do the sums. Do I reason correctly or not?
Is it the case that in classical (Newtonian) mechanics, there is no momentum associated with a wave? If so, then a quantum treatment is required to give the photons momentum. He has been claimed to have been using group velocity in his solution to the field density in the waveguide, which is not the speed of anything physical so should not have momentum associated with it.
Relativity also requires the strict equivalence of all inertial frames of reference. If a force is being produced without an equal and opposite reaction on something, surely this means that the total work done in different frames is different, by moving a net force through different distances in different frames, an objection that an equal and opposite force neatly makes constant. Do I reason correctly that lack of a reaction force would imply violation of conservation of energy as well as momnentum by the above argument?
It will be interesting to see where his work goes. His claimed forces are still small enough to be experimental error, given the cables and copious cooling air that will be disturbing his force balance. He has attracted funds from various sources, and has NASA and the Chinese space agencies interested, so I guess he is happy for the moment regardless of the physics.
Re: spaceship drive snake oil
Bjørn, Tue Sept 19 2006, 02:22PM
We have a thread about it here that got closed:
Neil has set the standard and if the replies are to the same standard then this thread will survive.
Bjørn, Tue Sept 19 2006, 02:22PM
We have a thread about it here that got closed:
Neil has set the standard and if the replies are to the same standard then this thread will survive.
Re: spaceship drive snake oil
Eric, Tue Sept 19 2006, 06:04PM
He has some way to account for conservation of energy, that the Q of the chamber and thus thrust drops as its velocity is increased so that lost em energy balances gained kinetic energy. This would seem to imply that there is some absolute frame of reference to measure the chamber velocity from. In other words, if you are flying along with your 'engine', by measuring Q you can deduce your velocity. This would seem to pose big problems for the theory of special relativity.
Looks like it shouldn't take much to reproduce his experiment, a scale, a magnetron and some sheet metal work... and a six pack to give you hope.
Eric, Tue Sept 19 2006, 06:04PM
He has some way to account for conservation of energy, that the Q of the chamber and thus thrust drops as its velocity is increased so that lost em energy balances gained kinetic energy. This would seem to imply that there is some absolute frame of reference to measure the chamber velocity from. In other words, if you are flying along with your 'engine', by measuring Q you can deduce your velocity. This would seem to pose big problems for the theory of special relativity.
Looks like it shouldn't take much to reproduce his experiment, a scale, a magnetron and some sheet metal work... and a six pack to give you hope.
Re: spaceship drive snake oil
Dr. Slack, Tue Sept 19 2006, 07:51PM
The main reaon I posted was to clarify my feeble understanding of physics. It's quite a (long) while since I did the first part of my degree in physics before switching to engineering, so I could use a bit of help from people who've done physics more deeply or more recently.
Does classical (Newtonian) physics have any concept of wave pressure, or does it need QM?
Is work done in different inertial frames equal, is this mandated by energy conservation?
Please confirm that is should be impossible to produce momentum conservation breaking predictions from relativity without having a mathematical error somewhere.
Does conservation of momentum strictly imply all forces must have an equal and opposite reaction?
At the simplest level, every interaction between a photon in the cavity and electrons in the walls of the cavity obeys the conservation laws, so there should be no way that an ensemble of them can break them.
Though switching between QM and classical approaches like group velocity is a good way to confuse oneself, or ones finacnial backers
Dr. Slack, Tue Sept 19 2006, 07:51PM
The main reaon I posted was to clarify my feeble understanding of physics. It's quite a (long) while since I did the first part of my degree in physics before switching to engineering, so I could use a bit of help from people who've done physics more deeply or more recently.
Does classical (Newtonian) physics have any concept of wave pressure, or does it need QM?
Is work done in different inertial frames equal, is this mandated by energy conservation?
Please confirm that is should be impossible to produce momentum conservation breaking predictions from relativity without having a mathematical error somewhere.
Does conservation of momentum strictly imply all forces must have an equal and opposite reaction?
At the simplest level, every interaction between a photon in the cavity and electrons in the walls of the cavity obeys the conservation laws, so there should be no way that an ensemble of them can break them.
Though switching between QM and classical approaches like group velocity is a good way to confuse oneself, or ones finacnial backers
Re: spaceship drive snake oil
Marko, Tue Sept 19 2006, 08:31PM
Newton itself probably didn't study radiation pressure itsef, but conservation of momentum is unique for everything and no force from 'inside' can move a body in a direction because of it's own reaction. No matter how our resonant cavity is shaped radiation pressures will always cancel out. (waverider can explain this better)
If you were able to ignore conservation of momentum you could make the motor go in one direction, then reverse it and accelerate in another direction virtually destroying the energy,
I guess conservation of energy is good enough reason why such a thing would't work.
If you overcome this by assuming Q is dependent on velocyty (Eric^^) you could have 'velocity' relative to nothing, and special relativity is stuffed.
Thing seems as impossible as making perpetuum mobile...
Marko, Tue Sept 19 2006, 08:31PM
Newton itself probably didn't study radiation pressure itsef, but conservation of momentum is unique for everything and no force from 'inside' can move a body in a direction because of it's own reaction. No matter how our resonant cavity is shaped radiation pressures will always cancel out. (waverider can explain this better)
If you were able to ignore conservation of momentum you could make the motor go in one direction, then reverse it and accelerate in another direction virtually destroying the energy,
I guess conservation of energy is good enough reason why such a thing would't work.
If you overcome this by assuming Q is dependent on velocyty (Eric^^) you could have 'velocity' relative to nothing, and special relativity is stuffed.
Thing seems as impossible as making perpetuum mobile...
Re: spaceship drive snake oil
Dr. Slack, Tue Sept 19 2006, 10:10PM
Look, the damned thing's impossible, if nobody is going to try to answer my very specific questions to try to clarify exactly why it's impossible, then this thread gets closed too.
Dr. Slack, Tue Sept 19 2006, 10:10PM
Look, the damned thing's impossible, if nobody is going to try to answer my very specific questions to try to clarify exactly why it's impossible, then this thread gets closed too.
Re: spaceship drive snake oil
Marko, Tue Sept 19 2006, 10:28PM
I tried to give he answer: it violates conservation of energy.
By simply driving our motor back and forth you can destroy energy.
Or imagine our reactionless motor is moving towards some point in space (exp. earth) having some kinetic energy, adn starts braking.
Once it stops, both it's kinetic and used braking energy are gone
With reactive drives, either mass (chemical etc.) or electromagnetic, both kinetic and 'braking' energy are transferred to exhaust, either ending as kinetic energy of exhausted particles or increased frequency of EM radiation due to doppler effect.
Momentum is always conserved no matter of drive type used...
And I don't know how could you help there in reality ;/
/me prepares to get flamed by everybody..
Marko, Tue Sept 19 2006, 10:28PM
I tried to give he answer: it violates conservation of energy.
By simply driving our motor back and forth you can destroy energy.
Or imagine our reactionless motor is moving towards some point in space (exp. earth) having some kinetic energy, adn starts braking.
Once it stops, both it's kinetic and used braking energy are gone
With reactive drives, either mass (chemical etc.) or electromagnetic, both kinetic and 'braking' energy are transferred to exhaust, either ending as kinetic energy of exhausted particles or increased frequency of EM radiation due to doppler effect.
Momentum is always conserved no matter of drive type used...
And I don't know how could you help there in reality ;/
/me prepares to get flamed by everybody..
Re: spaceship drive snake oil
Simon, Wed Sept 20 2006, 04:23AM
So, really, it's more that in Newton's time no one understood exactly what light was than that Newtonian physics couldn't handle this effect.
Imagine you're on the back of a truck going at 20m/s and you roll a 1kg ball forwards at an extra 1 m/s. From your point of view, the ball has .5*mvv=.5J of kinetic energy and when it hits the other end of the truck tray and stops it loses just that.
From the point of view of someone outside standing on the road, the ball is going at 21m/s and has 220.5J of kinetic energy. When it "stops" in the tray and is going at 20m/s, it has 200J of kinetic energy.
So from the point of view of the tray, the ball loses .5J of kinetic energy. From the point of view of the bystander it loses 20.5J.
Edit: I guess I'd better clarify. This is not a way of generating 20J of teh free energy, it is simply showing that when calculating energy you need to keep a consistent point of view. This 20J of "free energy" is like the 20m/s of "free velocity" you get when you change perspective from the truck to the roadside.
I have better things to study. It reeks of pseudoscience (albeit not as badly as some, but that's not saying much). It's not just the fact the drive is outlandish but the way that it's supposedly based on theory that no one's writing papers about.
Simon, Wed Sept 20 2006, 04:23AM
wrote ...
Does classical (Newtonian) physics have any concept of wave pressure, or does it need QM?
Newtonian physics specifically doesn't say much about light beyond its optical effects. (Newton himself thought light was made up from particles but that's slightly off track.) The momentum of a photon as calculated by QM, however, is ordinary momentum and you can use Newtonian physics to handle it (with the usual caveats).Does classical (Newtonian) physics have any concept of wave pressure, or does it need QM?
So, really, it's more that in Newton's time no one understood exactly what light was than that Newtonian physics couldn't handle this effect.
wrote ...
Is work done in different inertial frames equal, is this mandated by energy conservation?
Your concept of work and energy depends on your reference frame. This is easy to show.Is work done in different inertial frames equal, is this mandated by energy conservation?
Imagine you're on the back of a truck going at 20m/s and you roll a 1kg ball forwards at an extra 1 m/s. From your point of view, the ball has .5*mvv=.5J of kinetic energy and when it hits the other end of the truck tray and stops it loses just that.
From the point of view of someone outside standing on the road, the ball is going at 21m/s and has 220.5J of kinetic energy. When it "stops" in the tray and is going at 20m/s, it has 200J of kinetic energy.
So from the point of view of the tray, the ball loses .5J of kinetic energy. From the point of view of the bystander it loses 20.5J.
Edit: I guess I'd better clarify. This is not a way of generating 20J of teh free energy, it is simply showing that when calculating energy you need to keep a consistent point of view. This 20J of "free energy" is like the 20m/s of "free velocity" you get when you change perspective from the truck to the roadside.
wrote ...
Neglecting the measurements and the detail of the theory for the moment and going for first principles, my thoughts are as follows. Relativity is a self-consistent theory, and is also consistent with the conservation of both momentum and energy. Therefore any calculation done using it should produce predictions which are also consistent, it is not logically possible to produce a contradictory answer (like doing addition with integers, it can only produce only integers and not fractions). If they are not consistent with the conservation laws, it indicates that there is an error in the maths. Or he is using something other than relativity to do the sums. Do I reason correctly or not?
I think this is a reasonable enough argument. Relativity does incorporate conservation laws so if you can use relativity to break the conservation to break the conservation laws... well, you probably can't. At least, forget the drive, relativity would be broken.Neglecting the measurements and the detail of the theory for the moment and going for first principles, my thoughts are as follows. Relativity is a self-consistent theory, and is also consistent with the conservation of both momentum and energy. Therefore any calculation done using it should produce predictions which are also consistent, it is not logically possible to produce a contradictory answer (like doing addition with integers, it can only produce only integers and not fractions). If they are not consistent with the conservation laws, it indicates that there is an error in the maths. Or he is using something other than relativity to do the sums. Do I reason correctly or not?
wrote ...
He has some way to account for conservation of energy, that the Q of the chamber and thus thrust drops as its velocity is increased so that lost em energy balances gained kinetic energy. This would seem to imply that there is some absolute frame of reference to measure the chamber velocity from. In other words, if you are flying along with your 'engine', by measuring Q you can deduce your velocity. This would seem to pose big problems for the theory of special relativity.
When I read the New Scientist article I had similar thoughts. This guy seemed to be complaining that the drive didn't work so well at high velocity, which is an extremely odd thing to say for a relativistic effect. Unless perhaps the article really meant acceleration rather than actual velocity but frankly I don't care enough about this drive.He has some way to account for conservation of energy, that the Q of the chamber and thus thrust drops as its velocity is increased so that lost em energy balances gained kinetic energy. This would seem to imply that there is some absolute frame of reference to measure the chamber velocity from. In other words, if you are flying along with your 'engine', by measuring Q you can deduce your velocity. This would seem to pose big problems for the theory of special relativity.
I have better things to study. It reeks of pseudoscience (albeit not as badly as some, but that's not saying much). It's not just the fact the drive is outlandish but the way that it's supposedly based on theory that no one's writing papers about.
Re: spaceship drive snake oil
WaveRider, Wed Sept 20 2006, 07:57AM
The basic conservation laws in Relativity are the same in Newtonian mechanics (with minor modification).
Quantum mechanics is not necessary to show this invention does not work. The properties of radiation pressure were well known from Maxwell's electrodynamics in the 19th century..
In this thread.
it was generally established that it was BS. It is fairly straighforward to show that Shawyer (the inventor) made a critical mistake in his calculations regarding the radiation pressure on the cavity walls. In short, I am suprised that New Scientist published the article without running Shawyer's claims by someone with experience in electrodynamics. His mistake would have flunked him out of my EM theory class!
The fact that is has attracted funding is not a complete suprise, since Shawyer seems more of a insistent salesman than a competent engineer.
I know this thread should be locked, but it could be interesting to see if others on the forum understand why this invention cannot work. Who here is studying EM field theory this semester? If you are, let's here from you!!!
WaveRider, Wed Sept 20 2006, 07:57AM
The basic conservation laws in Relativity are the same in Newtonian mechanics (with minor modification).
1. Conservation of (rest) mass (in the absence of particle decay or creation).
2. Conservation of momentum
3. conservation of angular momentum
4. Conservation of charge
5. Conservation of energy
6. ......etc.
Quantum mechanics is not necessary to show this invention does not work. The properties of radiation pressure were well known from Maxwell's electrodynamics in the 19th century..
In this thread.
it was generally established that it was BS. It is fairly straighforward to show that Shawyer (the inventor) made a critical mistake in his calculations regarding the radiation pressure on the cavity walls. In short, I am suprised that New Scientist published the article without running Shawyer's claims by someone with experience in electrodynamics. His mistake would have flunked him out of my EM theory class!
The fact that is has attracted funding is not a complete suprise, since Shawyer seems more of a insistent salesman than a competent engineer.
I know this thread should be locked, but it could be interesting to see if others on the forum understand why this invention cannot work. Who here is studying EM field theory this semester? If you are, let's here from you!!!
Re: spaceship drive snake oil
Steve Conner, Wed Sept 20 2006, 09:51AM
I don't think this thread ought to be locked, since it seems to be a well mannered scientific debate. I did think of one thought experiment that seems to make the whole thing look stupid:
If his claim that the Q of an asymmetrical cavity depends on velocity is true, then someone would have noticed that microwave gear on board aircraft and spacecraft in motion had lower Q than it did on the ground. (Or higher, depending if the pointy end of the cavity was facing in the direction of travel...) As far as I know, nobody ever has noticed that, and there are some space probes with microwave equipment travelling at very high speeds.
If his claim is false, and the Q stays the same, then his engine is a perpetual motion machine, which makes it seem even less probable.
Steve Conner, Wed Sept 20 2006, 09:51AM
I don't think this thread ought to be locked, since it seems to be a well mannered scientific debate. I did think of one thought experiment that seems to make the whole thing look stupid:
If his claim that the Q of an asymmetrical cavity depends on velocity is true, then someone would have noticed that microwave gear on board aircraft and spacecraft in motion had lower Q than it did on the ground. (Or higher, depending if the pointy end of the cavity was facing in the direction of travel...) As far as I know, nobody ever has noticed that, and there are some space probes with microwave equipment travelling at very high speeds.
If his claim is false, and the Q stays the same, then his engine is a perpetual motion machine, which makes it seem even less probable.
Re: spaceship drive snake oil
Bjørn, Wed Sept 20 2006, 10:29AM
There are many things that points to this being complete nonsense with a high degree of certainty, but that does not prove anything.
Proving that this effect is not real is quite difficult and no amount of math will do that. If current theories are not in agreement with reality then it is the theories that needs to be modified.
We have two independent claims by Shawyer:
1. That some machine he built is generating thrust.
2. That he has some math that explains how it works.
The correctness of one does not affect the correctness of the other so they have to be evaluated separately.
To get a reasonable proof that the experiment is flawed or not we have to reproduce the experiment very accurately.
To get a good proof that the math is flawed we need to get hold of the complete set of equations and check if they are valid and free of assumptions. Showing that some other set of equations we make up ourselves does not generate this effect proves nothing.
It all really boils down to the principle that spectacular claims demands spectacular evidence. Shawyer has come up so short in that sense that there is little point in making any large efforts to verify his claims. Replicating the experiment might be worthwhile since it is pretty simple, if nothing else it can put a solid nail in the coffin of the whole idea.
Bjørn, Wed Sept 20 2006, 10:29AM
There are many things that points to this being complete nonsense with a high degree of certainty, but that does not prove anything.
Proving that this effect is not real is quite difficult and no amount of math will do that. If current theories are not in agreement with reality then it is the theories that needs to be modified.
We have two independent claims by Shawyer:
1. That some machine he built is generating thrust.
2. That he has some math that explains how it works.
The correctness of one does not affect the correctness of the other so they have to be evaluated separately.
To get a reasonable proof that the experiment is flawed or not we have to reproduce the experiment very accurately.
To get a good proof that the math is flawed we need to get hold of the complete set of equations and check if they are valid and free of assumptions. Showing that some other set of equations we make up ourselves does not generate this effect proves nothing.
It all really boils down to the principle that spectacular claims demands spectacular evidence. Shawyer has come up so short in that sense that there is little point in making any large efforts to verify his claims. Replicating the experiment might be worthwhile since it is pretty simple, if nothing else it can put a solid nail in the coffin of the whole idea.
Re: spaceship drive snake oil
WaveRider, Wed Sept 20 2006, 04:58PM
Shawyer's paper is here.
The variation of Q with velocity violates the premise that inertial frames are indistinguishable from one another... This alone should set alarm bells ringing
Here are some musings on field stress and radiation pressure. I start with a derivation and then attempt to mage some general statements about what the total force on the cavity walls will be like assuming sinusoidally varying EM firlds within.
This is a somewhat simpler deduction based in consevation of momentum.
And, a simple photon illustration.
In short, momentum conservation is the key.. Time averaging removes high-frequency components to the force. If no field energy escapes the cavity, there is no thrust.
WaveRider, Wed Sept 20 2006, 04:58PM
Shawyer's paper is here.
The variation of Q with velocity violates the premise that inertial frames are indistinguishable from one another... This alone should set alarm bells ringing
Here are some musings on field stress and radiation pressure. I start with a derivation and then attempt to mage some general statements about what the total force on the cavity walls will be like assuming sinusoidally varying EM firlds within.
This is a somewhat simpler deduction based in consevation of momentum.
And, a simple photon illustration.
In short, momentum conservation is the key.. Time averaging removes high-frequency components to the force. If no field energy escapes the cavity, there is no thrust.
Re: spaceship drive snake oil
Bored Chemist, Wed Sept 20 2006, 05:49PM
"In short, momentum conservation is the key.. "
I'm not sure it is; the very fact that he is putting this forward as a reactionless drive indicates that he doesn't consider momentum to be conserved in this case.
This is now a philosphical question- if you never consider anything that claims to violate your paradigm how will you ever know when it's time for a new paradigm?
I don't think it's likely to work- particularly since running it in reverse also seems to violate the conservation of energy.
On the other hand, I do accept that it is perfectly possible that those "laws" might be a simplification.
After all, mass was thought to be conserved until Einstein's work.
I don't think this bloke is the new Einstein; but just saying that you don't need to do the experiment because the result is impossible is exaclty the problem that Galileo faced from the "educated" men of his day.
Neil's comment about cooling drafts and cables is probably the explanation of the "force" measured here but that's a reason for doing a better experiment rather than saying "It is imposible because it breaches our dogma".
Bored Chemist, Wed Sept 20 2006, 05:49PM
"In short, momentum conservation is the key.. "
I'm not sure it is; the very fact that he is putting this forward as a reactionless drive indicates that he doesn't consider momentum to be conserved in this case.
This is now a philosphical question- if you never consider anything that claims to violate your paradigm how will you ever know when it's time for a new paradigm?
I don't think it's likely to work- particularly since running it in reverse also seems to violate the conservation of energy.
On the other hand, I do accept that it is perfectly possible that those "laws" might be a simplification.
After all, mass was thought to be conserved until Einstein's work.
I don't think this bloke is the new Einstein; but just saying that you don't need to do the experiment because the result is impossible is exaclty the problem that Galileo faced from the "educated" men of his day.
Neil's comment about cooling drafts and cables is probably the explanation of the "force" measured here but that's a reason for doing a better experiment rather than saying "It is imposible because it breaches our dogma".
Re: spaceship drive snake oil
Steve Conner, Wed Sept 20 2006, 05:49PM
I read his paper and he seems to have been pretty careful measuring the thrust. The only thing I can see going wrong is if he used electronic balances and the microwave leakage interfered with them. But even so he controlled for that by turning the thruster upside down to see if the measured force changed sign (which it did.)
Still, if I was going to invest in the guy, I'd want him to dangle his whole engine from a balance beam and show me it move when he turned the power on. He claimed a thrust of 0.214N/kW from his bigger engine, well over 20 grams, which I bet would easily move a steelyard type of beam even with a power cable at the fulcrum. Cooling air and water would mess things up, but I bet it would run fine for a few seconds without cooling.
Steve Conner, Wed Sept 20 2006, 05:49PM
I read his paper and he seems to have been pretty careful measuring the thrust. The only thing I can see going wrong is if he used electronic balances and the microwave leakage interfered with them. But even so he controlled for that by turning the thruster upside down to see if the measured force changed sign (which it did.)
Still, if I was going to invest in the guy, I'd want him to dangle his whole engine from a balance beam and show me it move when he turned the power on. He claimed a thrust of 0.214N/kW from his bigger engine, well over 20 grams, which I bet would easily move a steelyard type of beam even with a power cable at the fulcrum. Cooling air and water would mess things up, but I bet it would run fine for a few seconds without cooling.
shawyer wrote ...
In each series of tests, the test runs were repeatedly carried out with the thruster in both a nominal position (thrust direction vertically up, thus measured thrust is negative) and an inverted position (thrust direction vertically down, thus measured thrust is positive). In all tests the thruster gave the correct thrust direction...
Tests were also carried out with the thruster sealed into an airtight enclosure to calibrate out thermal buoyancy effects...
A total of 450 test runs were carried out using 5 different magnetrons. Input and resonant tuning positions were varied to give a range of thrust outputs from a maximum of 16mN, at optimum tuning, down to zero when totally detuned.
Substitution of the design parameters and measured Q into equation 10 gives a theoretical thrust output of 16.6 mN which is in close agreement with the thrust measured...
etc
In each series of tests, the test runs were repeatedly carried out with the thruster in both a nominal position (thrust direction vertically up, thus measured thrust is negative) and an inverted position (thrust direction vertically down, thus measured thrust is positive). In all tests the thruster gave the correct thrust direction...
Tests were also carried out with the thruster sealed into an airtight enclosure to calibrate out thermal buoyancy effects...
A total of 450 test runs were carried out using 5 different magnetrons. Input and resonant tuning positions were varied to give a range of thrust outputs from a maximum of 16mN, at optimum tuning, down to zero when totally detuned.
Substitution of the design parameters and measured Q into equation 10 gives a theoretical thrust output of 16.6 mN which is in close agreement with the thrust measured...
etc
Re: spaceship drive snake oil
WaveRider, Wed Sept 20 2006, 05:59PM
Bored Chemist: I am prepared to accept "new paradigms" as you put it, as long as what the person says makes sense. This does not make sense. It is a misrepresentation of what "group velocity" is about and I have grave doubts about the experimental evidence.
Shifts in Q (as Steve C indicates) do not occur in moving cavities. The "educated men" of Galileo's day would not look through the telescope at the moons of Jupiter. I am attempting to question the results of a probable scam artist who is misrepresenting a reasonably well understood phenomenon. Invoking the "closed mind" argument is a sign of pseudoscience in action! If you don't believe what I am saying, why not go through a century and a half of electrodynamics yourself. There is nothing that indicates that the fundamental conservation laws can be violated. It is through ignorance that these scam artists ply their wares..
If someone offers experimental and/or convincing theoretical evidence to the contrary, I will eat every one of my words... In the meantime, as I said previously, I will not be betting the retirement fund on this gamble.... Will you?
WaveRider, Wed Sept 20 2006, 05:59PM
Bored Chemist: I am prepared to accept "new paradigms" as you put it, as long as what the person says makes sense. This does not make sense. It is a misrepresentation of what "group velocity" is about and I have grave doubts about the experimental evidence.
Shifts in Q (as Steve C indicates) do not occur in moving cavities. The "educated men" of Galileo's day would not look through the telescope at the moons of Jupiter. I am attempting to question the results of a probable scam artist who is misrepresenting a reasonably well understood phenomenon. Invoking the "closed mind" argument is a sign of pseudoscience in action! If you don't believe what I am saying, why not go through a century and a half of electrodynamics yourself. There is nothing that indicates that the fundamental conservation laws can be violated. It is through ignorance that these scam artists ply their wares..
If someone offers experimental and/or convincing theoretical evidence to the contrary, I will eat every one of my words... In the meantime, as I said previously, I will not be betting the retirement fund on this gamble.... Will you?
Re: spaceship drive snake oil
Steve Conner, Wed Sept 20 2006, 06:06PM
Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize
Steve Conner, Wed Sept 20 2006, 06:06PM
Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize
Re: spaceship drive snake oil
WaveRider, Wed Sept 20 2006, 07:02PM
I'll cough up 50EUR to someone who does the experiment under Steve C's conditions and 150 EUR to the first person who does the experiment AND offers ideas on a coherent physical/mathematical theoretical basis for what is going on. In addition, if possible, we/he/she can submit a paper to Physical Review or IEEE Transactions.
WaveRider, Wed Sept 20 2006, 07:02PM
I'll cough up 50EUR to someone who does the experiment under Steve C's conditions and 150 EUR to the first person who does the experiment AND offers ideas on a coherent physical/mathematical theoretical basis for what is going on. In addition, if possible, we/he/she can submit a paper to Physical Review or IEEE Transactions.
Re: spaceship drive snake oil
Dr. Slack, Wed Sept 20 2006, 07:35PM
Thanks for the link to the paper.
I'm interested in figure 2.4, which shows a single photon pinging off both ends and walls. It appears to be valid to equate the group velocity with the speed of light resolved normal to the end plate, so either can be used to compute the force on the plates. However it also neatly shows that the photons change axial velocity with each interaction with the sloping walls, the mean of the arrival and departure angle on the walls is, as you would expect from geometrical optics, normal to the wall, thus has an axial component. From first principles without wading into the detail, I can guarrantee that in a sttioanry system, the force on the walls equals the difference of the forces on the ends.
The change of Q with speed is interesting. He is using the relatavistic expression for the addition of velcoties, and he is adding the spacecraft speed to the group velocity of the wave. I'm not sure that is a valid thing to do, as the photon is not moving at the group velocity axially, but at 'c' at some angle. This is where I appeal for somebody else to do the maths and say what the direction of the resultant photon path, still travelling at 'c' will be, as a result of adding the craft velocity.
Dr. Slack, Wed Sept 20 2006, 07:35PM
Thanks for the link to the paper.
I'm interested in figure 2.4, which shows a single photon pinging off both ends and walls. It appears to be valid to equate the group velocity with the speed of light resolved normal to the end plate, so either can be used to compute the force on the plates. However it also neatly shows that the photons change axial velocity with each interaction with the sloping walls, the mean of the arrival and departure angle on the walls is, as you would expect from geometrical optics, normal to the wall, thus has an axial component. From first principles without wading into the detail, I can guarrantee that in a sttioanry system, the force on the walls equals the difference of the forces on the ends.
The change of Q with speed is interesting. He is using the relatavistic expression for the addition of velcoties, and he is adding the spacecraft speed to the group velocity of the wave. I'm not sure that is a valid thing to do, as the photon is not moving at the group velocity axially, but at 'c' at some angle. This is where I appeal for somebody else to do the maths and say what the direction of the resultant photon path, still travelling at 'c' will be, as a result of adding the craft velocity.
Re: spaceship drive snake oil
Bored Chemist, Wed Sept 20 2006, 07:48PM
"Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize "
OK.
I take it you mean US dollars. IIRC the exchange rate is about $1.85 to the pound at the moment.
If someone takes up the challenge and provides the evidence I will send you a cheque for £100 (there's a bit of leeway for exchange rate changes there) and you can forward it (that way the recipient doesn't get stung for 2 sets of currency fees if they happen not to be in the UK.)
If anyone is planning to take this on please send a note to this thread - if there are lots of folks building kit and we only pay out for the "first to publish" then there will be a lot of disapointed people.
Of course nobody here is going to accept responsibility for anyone microwaving themself to death or anything like that. (Apart from anything else, that would be cheating- the microwaves are not meant to escape).
Don't get me wrong, I think this is almost certainly bull.
I'm just pointing out that if someone says "I have a toy that breaches the law of conservation of momentum" you can not logically say "That cannot be true because it would breach the law of conservation of momentum" as a refutation. (Of course, you an say that a zillion previous experiments have not shown that effect)
That would be the same argument as saying "I know God exists because it says so in the bible".
BTW, this looks a bit like buying a lottery ticket- I can afford to trash £100 without much trouble. If it happens to work then I get to be associated with one of mankind's greatest discoveries. All I have to do now is dream of fame and fortune until the "draw".
Bored Chemist, Wed Sept 20 2006, 07:48PM
"Bored Chemist: I'll offer $150 to the first 4hv member to do the experiment I proposed and post pictures and a movie, whether it generates any thrust or not. IF you (or waverider or anyone else) will agree to match my $150 prize "
OK.
I take it you mean US dollars. IIRC the exchange rate is about $1.85 to the pound at the moment.
If someone takes up the challenge and provides the evidence I will send you a cheque for £100 (there's a bit of leeway for exchange rate changes there) and you can forward it (that way the recipient doesn't get stung for 2 sets of currency fees if they happen not to be in the UK.)
If anyone is planning to take this on please send a note to this thread - if there are lots of folks building kit and we only pay out for the "first to publish" then there will be a lot of disapointed people.
Of course nobody here is going to accept responsibility for anyone microwaving themself to death or anything like that. (Apart from anything else, that would be cheating- the microwaves are not meant to escape).
Don't get me wrong, I think this is almost certainly bull.
I'm just pointing out that if someone says "I have a toy that breaches the law of conservation of momentum" you can not logically say "That cannot be true because it would breach the law of conservation of momentum" as a refutation. (Of course, you an say that a zillion previous experiments have not shown that effect)
That would be the same argument as saying "I know God exists because it says so in the bible".
BTW, this looks a bit like buying a lottery ticket- I can afford to trash £100 without much trouble. If it happens to work then I get to be associated with one of mankind's greatest discoveries. All I have to do now is dream of fame and fortune until the "draw".
Re: spaceship drive snake oil
Steve Conner, Wed Sept 20 2006, 08:40PM
Yes I do mean US dollars. Thanks for your support BC!
I guess I should also define that the money (my $150 plus anything anyone else pledges) will go to the first person to post pictures of their experiment, and a link to a movie, on 4hv. We'll need some kind of proof that the pictures and movie were made by you.
Also, as a minimum I think I'd like to see something like a flashlight bulb lit by a small coupling loop in the cavity, to prove that you really did bother to generate some microwaves in there. I'm sure WaveRider can work out what size the coupling loop should be, to make sure the bulb won't light unless you hit resonance with a decent Q factor.
WaveRider: It would be cool to get a paper in some journal, jointly authored by you and a couple of us. Or maybe you could give the experiment as a project to one of your students? Now I think about it, the hardest part of the whole thing is probably designing a truncated conical cavity that has a resonant mode at 2.45GHz: we could use your help with that.
Steve Conner, Wed Sept 20 2006, 08:40PM
Yes I do mean US dollars. Thanks for your support BC!
I guess I should also define that the money (my $150 plus anything anyone else pledges) will go to the first person to post pictures of their experiment, and a link to a movie, on 4hv. We'll need some kind of proof that the pictures and movie were made by you.
Also, as a minimum I think I'd like to see something like a flashlight bulb lit by a small coupling loop in the cavity, to prove that you really did bother to generate some microwaves in there. I'm sure WaveRider can work out what size the coupling loop should be, to make sure the bulb won't light unless you hit resonance with a decent Q factor.
WaveRider: It would be cool to get a paper in some journal, jointly authored by you and a couple of us. Or maybe you could give the experiment as a project to one of your students? Now I think about it, the hardest part of the whole thing is probably designing a truncated conical cavity that has a resonant mode at 2.45GHz: we could use your help with that.
Re: spaceship drive snake oil
AndrewM, Wed Sept 20 2006, 08:43PM
Lets see some dimensions for this fancy waveguide thinger, and I might be up for building it.
AndrewM, Wed Sept 20 2006, 08:43PM
Lets see some dimensions for this fancy waveguide thinger, and I might be up for building it.
Re: spaceship drive snake oil
Dr. Slack, Wed Sept 20 2006, 10:06PM
Now I've read his paper, I'm starting to do all sorts of thought experiments.
Consider a wide cylindrical cavity (simpler than conical). Photons travel pure axially, and bounce losslesly between two plane mirrors. Consider a pair of photons which bounce off the two mirrors at the same instant, producing two equal and opposite impulses. Now shift your frame of reference to observing this arrangement going hurtling by at 3km/s.
In my stationary frame, the photons still travel at 'c'. However the mirrors are doing 3km/s. This means that the photon hitting the back mirror will pick up energy and become blue-shifted, thus carrying more momentum, and when hitting the receding front mirror will become red-shifted and carry less. However, each mirror supplies the same delta (blue-red) or (red-blue) so the force at each end is still the same. So far, so good.
However, one casualty of relativity is simultaneity, and it bites by noticing that the front receding mirror gets hit slightly later than the rear advancing mirror. This phase shift appears to mean that the whole assembly is subject to a rearwards impulse for a small time before getting the frontwards impulse. The result of an impulse is a deltaV. Equal and opposite deltaVs seperated in time integrate to a small displacement. The displacemtnt occurs every photon transit, so that equates to a small net velocity.
Now what the hell's that about? I take a box of photons, and as a result of looking at it at a certain speed, it contrives to go at a different speed. What (if anything) have I done wrong?
It's nothing to do with Lorentz foreshortening. In our frame, the box has shrunk a little, and is the same front to back as well as back to front. In the frame of either photon, the box is zero-length.
I like the idea of reproducing the experiment by the way. In fact in terms of potentially ground-breaking science it's probably one of the most practical experiments to stage, I wouldn't be surprised if most of us haven't already got a magnetron or three lying about in the junk box.
Dr. Slack, Wed Sept 20 2006, 10:06PM
Now I've read his paper, I'm starting to do all sorts of thought experiments.
Consider a wide cylindrical cavity (simpler than conical). Photons travel pure axially, and bounce losslesly between two plane mirrors. Consider a pair of photons which bounce off the two mirrors at the same instant, producing two equal and opposite impulses. Now shift your frame of reference to observing this arrangement going hurtling by at 3km/s.
In my stationary frame, the photons still travel at 'c'. However the mirrors are doing 3km/s. This means that the photon hitting the back mirror will pick up energy and become blue-shifted, thus carrying more momentum, and when hitting the receding front mirror will become red-shifted and carry less. However, each mirror supplies the same delta (blue-red) or (red-blue) so the force at each end is still the same. So far, so good.
However, one casualty of relativity is simultaneity, and it bites by noticing that the front receding mirror gets hit slightly later than the rear advancing mirror. This phase shift appears to mean that the whole assembly is subject to a rearwards impulse for a small time before getting the frontwards impulse. The result of an impulse is a deltaV. Equal and opposite deltaVs seperated in time integrate to a small displacement. The displacemtnt occurs every photon transit, so that equates to a small net velocity.
Now what the hell's that about? I take a box of photons, and as a result of looking at it at a certain speed, it contrives to go at a different speed. What (if anything) have I done wrong?
It's nothing to do with Lorentz foreshortening. In our frame, the box has shrunk a little, and is the same front to back as well as back to front. In the frame of either photon, the box is zero-length.
I like the idea of reproducing the experiment by the way. In fact in terms of potentially ground-breaking science it's probably one of the most practical experiments to stage, I wouldn't be surprised if most of us haven't already got a magnetron or three lying about in the junk box.
Re: spaceship drive snake oil
Conundrum, Wed Sept 20 2006, 10:33PM
Still pretty interesting. I did however notice one minor detail in the original article, that the Q may well drop if the chamber is accelerated.
I'd have to do a detailed analysis to be sure but this in itself might be enough to verify CoE, in that acceleration is therefore impossible without moving reaction mass.
-A
Conundrum, Wed Sept 20 2006, 10:33PM
Still pretty interesting. I did however notice one minor detail in the original article, that the Q may well drop if the chamber is accelerated.
I'd have to do a detailed analysis to be sure but this in itself might be enough to verify CoE, in that acceleration is therefore impossible without moving reaction mass.
-A
Re: spaceship drive snake oil
AndrewM, Wed Sept 20 2006, 11:51PM
As I pondered the way (judging from the photograph) I might build this thing, and how I might test it, something struck me:
From the original article
Why do you suppose it requires shielding?
AndrewM, Wed Sept 20 2006, 11:51PM
As I pondered the way (judging from the photograph) I might build this thing, and how I might test it, something struck me:
From the original article
Enclosed in an EMC enclosure for safety reasons... The force motor and microwave generator weigh only 9.4kg, the remaining weight is that of the EMC enclosure.
Why do you suppose it requires shielding?
Re: spaceship drive snake oil
Bjørn, Thu Sept 21 2006, 12:55AM
I believe that a careful engineer should always use shielding when working with invisible radiation that could cause permanent damage and or interfere with instruments.
If he added the shielding because he was cooking the environment then it is a bad sign but it might be completely innocent.
Bjørn, Thu Sept 21 2006, 12:55AM
I believe that a careful engineer should always use shielding when working with invisible radiation that could cause permanent damage and or interfere with instruments.
If he added the shielding because he was cooking the environment then it is a bad sign but it might be completely innocent.
Re: spaceship drive snake oil
Simon, Thu Sept 21 2006, 02:31AM
If you're going to put a prize on constructing a test, you might want to give specific details about what you want. You want a proper test.
This story is relevant here. Remember that the only evidence that this works is a guy who likes this theory and has built this device and who claims it produces some incredibly tiny thrust.
Simon, Thu Sept 21 2006, 02:31AM
wrote ...
Don't get me wrong, I think this is almost certainly bull.
I'm just pointing out that if someone says "I have a toy that breaches the law of conservation of momentum" you can not logically say "That cannot be true because it would breach the law of conservation of momentum" as a refutation. (Of course, you an say that a zillion previous experiments have not shown that effect)
That would be the same argument as saying "I know God exists because it says so in the bible".
That's true but the other statement that goes, "I've used relativity to break the law of momentum conservation," is dodgy.Don't get me wrong, I think this is almost certainly bull.
I'm just pointing out that if someone says "I have a toy that breaches the law of conservation of momentum" you can not logically say "That cannot be true because it would breach the law of conservation of momentum" as a refutation. (Of course, you an say that a zillion previous experiments have not shown that effect)
That would be the same argument as saying "I know God exists because it says so in the bible".
If you're going to put a prize on constructing a test, you might want to give specific details about what you want. You want a proper test.
wrote ...
Who here is studying EM field theory this semester? If you are, let's here from you!!!
I am. Maybe I'll read your notes later.Who here is studying EM field theory this semester? If you are, let's here from you!!!
This story is relevant here. Remember that the only evidence that this works is a guy who likes this theory and has built this device and who claims it produces some incredibly tiny thrust.
wrote ...
In short, I am suprised that New Scientist published the article without running Shawyer's claims by someone with experience in electrodynamics. His mistake would have flunked him out of my EM theory class!
New Scientist is a pretty good magazine. I read it. In spite of that, New Scientist does jump on the occasional BS bandwagon. ZeoSync, the algorithm that compresses anything (great, I'll compress everything down to nothing...). The latest uncrackable coding scheme (i.e. "Here's a code I'm not smart enough to break!"). Etc, etc, etc. Publication in New Scientist is not a mark of authenticity.In short, I am suprised that New Scientist published the article without running Shawyer's claims by someone with experience in electrodynamics. His mistake would have flunked him out of my EM theory class!
Re: spaceship drive snake oil
Bored Chemist, Thu Sept 21 2006, 06:00AM
Would this "work" with a tapered cylinder of gas?
The speeds of typical gas molecules are not close to c so the effect would be small but their mass is huge compared to a µwave photon.
Bored Chemist, Thu Sept 21 2006, 06:00AM
Would this "work" with a tapered cylinder of gas?
The speeds of typical gas molecules are not close to c so the effect would be small but their mass is huge compared to a µwave photon.
Re: spaceship drive snake oil
WaveRider, Thu Sept 21 2006, 09:25AM
Bored Chemist: You bring up a very good point. I will add to your suggesttion by saying that sound-waves in a resonator could exhibit a similar effect (altho' the mechanics are slightly different, momentum transfer by wave energy is a fundamental effect). Sound waves in an acoustic waveguide exhibit phase and group velocities, just like EM waves.
SteveC: I'll give some thought to the resonator dimesions. I think Shawyer's resonator was quite large (altho' he gives no specific dimensions, resonant modes at 2.45 GHz are so close together in frequency that minor tweaking of the side wall was all that's needed to achieve resonance in one of the cavity modes).
Using a "dip wavemeter" approach is a convenient way to find resonance. The whole thing may need to be pressurised with dry nitrogen to avoid arcing when resonance is achieved at high power... Also, everything would need to be enclosed on a large balance (energy source, etc.) The desired effect is so small, great care would have to be taken to eliminate air currents, etc. for a fair experiment to be carried out.
Note that an experiment using light should work just as well if you have access to an optical lab and lasers.. A Fabry-Perot resonator with one spherical and a flat reflector will exhibit the same "tapered" field profile....but we don't have those side walls to press against.. Damn! How do those bloody waves stay confined with nothing to "push against" on the sides??!!!
A pertinent thought experiment on specular reflection to consider (hint: assume plane waves inpinging on mirror surface):
WaveRider, Thu Sept 21 2006, 09:25AM
Bored Chemist: You bring up a very good point. I will add to your suggesttion by saying that sound-waves in a resonator could exhibit a similar effect (altho' the mechanics are slightly different, momentum transfer by wave energy is a fundamental effect). Sound waves in an acoustic waveguide exhibit phase and group velocities, just like EM waves.
SteveC: I'll give some thought to the resonator dimesions. I think Shawyer's resonator was quite large (altho' he gives no specific dimensions, resonant modes at 2.45 GHz are so close together in frequency that minor tweaking of the side wall was all that's needed to achieve resonance in one of the cavity modes).
Using a "dip wavemeter" approach is a convenient way to find resonance. The whole thing may need to be pressurised with dry nitrogen to avoid arcing when resonance is achieved at high power... Also, everything would need to be enclosed on a large balance (energy source, etc.) The desired effect is so small, great care would have to be taken to eliminate air currents, etc. for a fair experiment to be carried out.
Note that an experiment using light should work just as well if you have access to an optical lab and lasers.. A Fabry-Perot resonator with one spherical and a flat reflector will exhibit the same "tapered" field profile....but we don't have those side walls to press against.. Damn! How do those bloody waves stay confined with nothing to "push against" on the sides??!!!
A pertinent thought experiment on specular reflection to consider (hint: assume plane waves inpinging on mirror surface):
Re: spaceship drive snake oil
Dr. Slack, Thu Sept 21 2006, 01:08PM
One thing that bugs me having read his v9.3 paper is that he says the thrusts he measures are consistent with his theory. Now his theory looks BS, because it ignores the walls, or rather assumes that the photon pressure is normal to the axis rather than normal to the wall surface - the latter true case generates precsiely the reverse force on the walls to balance the net difference between the flat ends. Early figures in that paper use free space arguments, it appears based on the relativistic idea that regardless of the speed of the engine, light in our frame or the engine's frame travels at 'c', to neglect the rest of the apparatus and consider only the end walls.
I wonder, call me suspcious if you like, whether he has a choke seal at each end isolating the walls, and the ends only are connected to his balance? This would be consistent with his implied assertion that the walls contribute nothing. Can you get a choke seal to maintain that Q? Just a thought. However, that sort of arrangement would be pretty far out when it would be far simpler to make the whole thing in one.
Waverider, your optical resolnator won't work, the light is travelling essentially axially at both ends, group velocity = c, so equal foce at each end. It's confined by being a diffraction limited beam, not by bouncing off those sidewalls which reduce the group velocity.
Dr. Slack, Thu Sept 21 2006, 01:08PM
One thing that bugs me having read his v9.3 paper is that he says the thrusts he measures are consistent with his theory. Now his theory looks BS, because it ignores the walls, or rather assumes that the photon pressure is normal to the axis rather than normal to the wall surface - the latter true case generates precsiely the reverse force on the walls to balance the net difference between the flat ends. Early figures in that paper use free space arguments, it appears based on the relativistic idea that regardless of the speed of the engine, light in our frame or the engine's frame travels at 'c', to neglect the rest of the apparatus and consider only the end walls.
I wonder, call me suspcious if you like, whether he has a choke seal at each end isolating the walls, and the ends only are connected to his balance? This would be consistent with his implied assertion that the walls contribute nothing. Can you get a choke seal to maintain that Q? Just a thought. However, that sort of arrangement would be pretty far out when it would be far simpler to make the whole thing in one.
Waverider, your optical resolnator won't work, the light is travelling essentially axially at both ends, group velocity = c, so equal foce at each end. It's confined by being a diffraction limited beam, not by bouncing off those sidewalls which reduce the group velocity.
Re: spaceship drive snake oil
Bored Chemist, Thu Sept 21 2006, 05:25PM
I had a bit more of a think about the gas idea. I'm the first to admit that my maths is lousy and my understanding of special (or even general) relativity is pretty poor too.
Normally with a gas bottle- even a tapered one- the forces due to the pressure all cancel out- the same ought to be true with radiation pressure but- it is claimed- special relativity ensures this doesn't happen. There's somestrange "leftover" force.
I understand that all motion is "relativistic" rather than Newtonian, but for most things the difference is too small to notice. This guy's "magic" relativistic effect seems to be in addition to the expected Newtonian one (where all the forces cancel out) so how big is it?
If we got a tapered gas bottle of helium at room temperature and 1 bar pressure the atoms would be moving at roughly 1000 m/sec. Roughly 5 orders of magnitude less than C.
Lots of the equations associated with relativity seem to include a term in (v/c) squared.
Comparing µwave photons with a velocity of c; against helium atoms with a velocity roughly C/10^5 would sugest to me that the "magic" relativistic effect would be something like 10^10 times smaller for the gas.
Looks like a complete non- starter.
But, what this guy claims to be working with is radiation pressure- that's a very small effect. I can easily fill a gas bottle to 100 bar. On paper I can get 1000 bar with no difficulty.
Also because he is working with a mess of power cables; cooling fans; circulating DC currents in the earth's magnetic field etc. he's pushing it to measure the force acurately (because there are heaps of other forces to deal with). He seems to be strugling to get better than a resolution of 1 in 10^4 (a gram in 10 Kg).
For a gas bottle it's just that- a bottle with gas in it. I can weigh that in the lab to a part in 10^7 resolution easily (accuracy is another matter- but I just need to see if it changes when I put it upside down).
If I can get 10^7 times more pressure (and I think that's possible- do radiation pressures in this bloke's experiment get to a milibar or so?) and if I can get 10^3 fold better weight resolution then I'm on to a winner.
Best of all- this system needs no magnetron or other power source. I can get 2 of them pointing in oposite directions to produce a couple and rotate the shaft of a generator. I can use another pair to keep the stator from spinning.
Can someone who knows about relativity check this idea- if there's no "magic" difference between the effect of a photon and the effect of a helium atom then we have a free energy machine and we can call it a day (I will still cough up £100 for the first person to check it experimentally with a reasonable attempt to replicate the original work). It'd also help if someone could let me know what the radiation pressure in that waveguide of his is likely to be.
(yes, I know that variations of the air pressure will cause an apparent change in weight rather bigger than 1 in 10^7- that's why they invented vacuum balances)
Bored Chemist, Thu Sept 21 2006, 05:25PM
I had a bit more of a think about the gas idea. I'm the first to admit that my maths is lousy and my understanding of special (or even general) relativity is pretty poor too.
Normally with a gas bottle- even a tapered one- the forces due to the pressure all cancel out- the same ought to be true with radiation pressure but- it is claimed- special relativity ensures this doesn't happen. There's somestrange "leftover" force.
I understand that all motion is "relativistic" rather than Newtonian, but for most things the difference is too small to notice. This guy's "magic" relativistic effect seems to be in addition to the expected Newtonian one (where all the forces cancel out) so how big is it?
If we got a tapered gas bottle of helium at room temperature and 1 bar pressure the atoms would be moving at roughly 1000 m/sec. Roughly 5 orders of magnitude less than C.
Lots of the equations associated with relativity seem to include a term in (v/c) squared.
Comparing µwave photons with a velocity of c; against helium atoms with a velocity roughly C/10^5 would sugest to me that the "magic" relativistic effect would be something like 10^10 times smaller for the gas.
Looks like a complete non- starter.
But, what this guy claims to be working with is radiation pressure- that's a very small effect. I can easily fill a gas bottle to 100 bar. On paper I can get 1000 bar with no difficulty.
Also because he is working with a mess of power cables; cooling fans; circulating DC currents in the earth's magnetic field etc. he's pushing it to measure the force acurately (because there are heaps of other forces to deal with). He seems to be strugling to get better than a resolution of 1 in 10^4 (a gram in 10 Kg).
For a gas bottle it's just that- a bottle with gas in it. I can weigh that in the lab to a part in 10^7 resolution easily (accuracy is another matter- but I just need to see if it changes when I put it upside down).
If I can get 10^7 times more pressure (and I think that's possible- do radiation pressures in this bloke's experiment get to a milibar or so?) and if I can get 10^3 fold better weight resolution then I'm on to a winner.
Best of all- this system needs no magnetron or other power source. I can get 2 of them pointing in oposite directions to produce a couple and rotate the shaft of a generator. I can use another pair to keep the stator from spinning.
Can someone who knows about relativity check this idea- if there's no "magic" difference between the effect of a photon and the effect of a helium atom then we have a free energy machine and we can call it a day (I will still cough up £100 for the first person to check it experimentally with a reasonable attempt to replicate the original work). It'd also help if someone could let me know what the radiation pressure in that waveguide of his is likely to be.
(yes, I know that variations of the air pressure will cause an apparent change in weight rather bigger than 1 in 10^7- that's why they invented vacuum balances)
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