I just read about this in New Scientist. Even if the article had gone into detail regarding the physics, I couldn't have followed it. A brief synopsis:

A method of propulsion has apparently been devised based on resonating microwaves in a waveguide. Microwaves are created within a chamber by a magnetron. No photons need to escape from the device. Rather, the resonating radiation imparts unequal forces on the different walls of the chamber as the photons bounce back and forth, causing a net force in one direction. It seems that the engine will be at least as effective as an ion drive, with the added bonus that it needs no propellant. It may even generate enough force to accelerate itself (and a good bit more) at 1G, allowing it to hover (with some well-chosen high-temperature superconductors). Seems to good to be true to me, but what do I know?

Here's (http://www.theengineer.co.uk/Articles/Article.aspx?liArticleID=295931) somewhere to start. Please give me your opinions.

DAMM IT... i had worked on similar ideas, only in my head... and hoped to pursue the research someday...

i guess, i wont be getting the nobel prize.

but im glad someone worked it out... it could change the destiny of mankind.

-MT

I very much doubt that this works. Feels to much like a scam, or just plain honest error. I am willing to hold off judgement untill I see some solid math and some replication of the experiment though.

One other thing, iirc, superconductors don't work well at microwave frequencies.

My opinion is that I should not tell them the right way to fix this up and should patent my idea and make them pay good money for it. It's too damn simple.

it is anything but simple.

-MT

It seems that the engine will be at least as effective as an ion drive.
So not much of a breakthrough then.

It may even generate enough force to accelerate itself (and a good bit more) at 1G,
Wow wee :rolleyes:
(with some well-chosen high-temperature superconductors). So it will need to carry some kind of fuel to generate the energy to keep this cool yeah?
Seems to good to be true to me, but what do I know?
No not really, but it sounds a lot more exciting than it is to me.

I just bought that issue of New Scientist yesterday, and haven't got around to reading the article yet. At first glance, it seems to me that the device would violate Newton's third law, but I don't know enough about it yet to really comment.

I'll be back...

. At first glance, it seems to me that the device would violate Newton's third law.

My thoughts entirely, and when I have finished my chores I'll nip into town and pick up a copy of 'New Scientist' too. I can't see how it can work, to be honest.

The issue for it not working if it accelerates, stated in the linked article smells to me too. If it is an enclosed system, how does it know it's motion relative to an external frame of reference?

Actually, if i read this right, it's using radiation as propellent. Radiation does in fact have mass. You could theoredically power a spacecraft with a laser because although the mass of the photons are infintesimally small, they're moving at damn-close to C, giving a higher reaction to the ship and moving it forward.

But, assuming you had a ship with a nuclear reactor on it, and not a little nuclear sub reactor but one that powers several cities (huge reactor) of about a GW of power, and all of that power went into the laser/gamma laser/microwave (which wouldn't happen due to waste heat), you'd only be able to accelerate by 1m/s every few hours. A system like this makes up for ultra-small propellent use for ginormous power requirements.

But I don't know, maybe they're doing something different if they claim to be able to get a full gee of acceleration here using just solar power, which might be only a few kilowatts...

As near as I can tell from the linked article, the device isn't radiating. If it were based on radiation reaction, why bother with microwaves? A few incandescent light bulbs and a reflector will beat the pants off it both in price and weight.

They apparently think they have found a loophole in Newton's laws, but I suspect they're mistaken. I would sure like to know more about this though.

>> edit Here's a link to an older and somewhat more detailed article on Eureka. http://www.shelleys.demon.co.uk/fdec02em.htm

im so upset... its so simple.

with perfected resonating chambers, our world will soon be changed.

unless its all a scam, let us pray that it is not, for with such, all the starwars technology of floating vehicles could be ours.


IF IT IS A SCAM, i will be even more upset.

-MT

imaplanck, are you really so unimaginative? If this device can develop a thrust of 1G without expelling any propellant, all it needs is a power source. You could accelerate at 1G half-way to your destination, then decelerate for the remainder. It would open up the solar system.

Does it heat up burgers?

Really though, could they contain the radiation or would a geiger counter be going crazy in the cockpit?

It's just microwaves. Non-ionizing.

From the reference in first post:

"...Because of the difference in wave velocity, being higher at one end that the other, there is a momentum transfer. The result is a measurable net force from the cavity against its surroundings. ..."

The claim seems to be that the "faster waves" reflection off one end push harder than the slower ones reflecting off the other. That seems true, but to see how silly the device is as a propulsion system with no emissions, not even radiations (which would work) let us consider a similar system using BBs that make perfectly elastic collisions at opposite ends of a closed cylinder:

The only way the BBs can transfer more momentum to end A than end B is if the are going faster (like his waves) when they hit end A than when the hit end B. But the BBs rebounding from end A after elastic collision will have the same velocity as just before they hit end A (Best to think of all this in the reference frame where the ends A & B are stationary.) Thus, to make them hit end B later with less velocity they must pass thru some electromagnetic retarding field device in the center of the cylinder. Likewise those BBs bouncing elastically off end B need to be accelerated by this device to get them back up to the higher speed for striking end A.

Well, as Newton said quite while back; if the device in the center of the cylinder is applying a force to accelerate the BB going from B towards A and another force to decelerate them when going from A towards B, then a reaction force is acting on it also. The total force on the rocket is the sum of the net "end forces" and the forces acting on the central device, or zero total force acts on the rocket.

I suggest you not put your money into the IPO when it comes out. Let some other idiot do so.

imaplanck, are you really so unimaginative?
No im just going on what you have posted here. Looking at that it doesn't seem remarkably impressive. Thats if it doesn't break any of the fundamental laws, which is of course suspect to begin with .

It would open up the solar system.
By what magnitude? You seem to be highly exaggerating the implications of this flying microwave oven.

You seem to be highly exaggerating the implications of this flying microwave oven.
:p

‘The next stage would ideally use technology employed by high-energy physics. If we approach a condition where we use the same shape cavity but at absolute zero and made from Niobium, the resistance drops to near zero and the Q value increases by several orders of magnitude.’
How much energy is required to drop the temperature to absolute 0. Can we even do that with our technology? How easy it is to get some Niobium?

Shawyer cautions that the calculations only work for static thrusts. ‘You can’t beat the laws of physics. If it is used to accelerate, the Q value drops. It is best used to lift a body and oppose a force, for instance to counteract gravity. It cannot be used to accelerate further.’
Sounds kinda hopeless... :confused:

They may want to use a Gaussian pulse.

we cannot get to absolute zero.... period.. so dont bother trying.
it would require to much energy.

we can reach 3-5 degrees above zero... which turns most things into superconductors....

noibium is availible, it is probubly to be used due to its strenght at that temp... since many metals become very fragile and brittle at that temp.

im not sure at what temp it become superconductive,, but if its over 7 degrees we are in buisness, since liquid nitrogen is readily avalible.

-MT

I've read the article now.

I don't think this can work. The article talks about microwaves bouncing off the two ends of a cyclinder which is bigger at one end than the other, and thereby causing a larger force on the large end than on the small end. But that totally ignores the microwaves bouncing off the tapered side walls. When you add up all the forces, they will give a net force of zero.

With reference to Newton's third law, if you're going to propel something it needs to push against something else in order to accelerate. This device pushes against nothing, since the microwaves do not exist the container.

There's some mumbo-jumbo about relativistic effects being important, but I can't understand how they'd make any difference from the New Scientist article.

I wonder whether the inventor has actually published a peer-reviewed paper on his ideas...

I mentioned this before, but superconductors don't work well at microwave frequencies. Most drop out of superconductivity around 500 MHz, iirc.

Isn't the proper term "reactionless drive".

MT,
im not sure at what temp it become superconductive,, but if its over 7 degrees we are in buisness, since liquid nitrogen is readily avalible.
CERN and Fermilab have ran tests on niobium-coated cavities that are superconductive at 4.5K, which are cooled by liquid nitrogen.

I have two or three links to papers concerning the cavities. I do see that a
Lorentz force producing a torque is noted, but I have no idea how well that could translate into a viable propulsive force in a closed system. The links:
http://tesla.desy.de/new_pages/TDR_CD/PartII/chapter02/references/benvenuti2.pdf
Here is the paper where they speak of the Lorentz force:
http://arxiv.org/ftp/cond-mat/papers/0308/0308266.pdf
This one is interesting as they propose a high rate pulsed power to eliminate a problem with a magnetic flux developing:
http://www.lns.cornell.edu/public/SRF/1998/SRF980804-06/SRF980804-06.pdf

I mentioned this before, but superconductors don't work well at microwave frequencies. Most drop out of superconductivity around 500 MHz, iirc.


(Lets assume this concept works for a minute, if we may?)

So why not use visible wavelengths on this, anyone see anything preventing that? im thinking of the developement of the MASER here.

It seems that it will be at least as effective as ion drive. So not much of a breakthrough then.
Huh! :eek:
Ion drive is way more effective than rockets, chemical or solid. An alternative way of generating thrust in space with lower propellant requirements could be hugely important.
Specific impulse for a typical ion drive is 3000 seconds, about the same as a jet engine, whereas rockets come in between 250 (solid) and 450 (liquid).

It's not rocket science! Oops, it is rocket science. :o
So it will need to carry some kind of fuel to generate the energy to keep this cool yeah?Not if room temperature superconductors are used. Recent research strongly suggests these can be produced within the decade.

Huh! :eek:
Ion drive is way more effective than rockets, chemical or solid. An alternative way of generating thrust in space with lower propellant requirements could be hugely important.
Specific impulse for a typical ion drive is 3000 seconds, about the same as a jet engine, whereas rockets come in between 250 (solid) and 450 (liquid)..
Duh! No! it's not much of an advancement in terms of an ion drive. Ion drives are already chemical propellentless, hence the voyager mission is at the edge of the solar system with fuel still left.
It's not rocket science! Oops, it is rocket science. :o Not if room temperature superconductors are used. Recent research strongly suggests these can be produced within the decade.
Yeah really :rolleyes: Other reaserch also suggest that this grail will never happen, in any case the submition stated a high temperature superconductor. Twat.

Duh! No! it's not much of an advancement in terms of an ion drive. Ion drives are already chemical propellentless, hence the voyager mission is at the edge of the solar system with fuel still left.

Yeah really :rolleyes: Other reaserch also suggest that this grail will never happen, in any case the submition stated a high temperature superconductor. Twat.If you are going to call someone a 'twat' you might try to get your facts right.

Your statement "Ion drives are already chemical propellentless" is ambiguous to the point of being meaningless. What do you imagine they expel from their exhausts if it is not a chemical?

The Voyager craft were most certainly not ion drive vehicles. They were launched by conventional chemical rockets, achieving the bulk of their complex manouvering via gravity assist, with minor contributions from onboard thrusters.

Your remarks on superconductors betray a surprising ignorance on your part. Room temperature superconductors are high temperature superconductors. This makes your ad hominem somewhat sad.

Your statement "Ion drives are already chemical propellentless" is ambiguous to the point of being meaningless. What do you imagine they expel from their exhausts if it is not a chemical? Ionized gas! You know as well as I do that for all intents and purposes it is not a chemical propellent. A standard chemical reaction such as hydrogen and oxygen would be spent in a fraction of the time in comparison.


The Voyager craft were most certainly not ion drive vehicles. They were launched by conventional chemical rockets, achieving the bulk of their complex manouvering via gravity assist, with minor contributions from onboard thrusters.

OK I'll give you that one. I never reference anything jsut to post with a bunch of saps.

Your remarks on superconductors betray a surprising ignorance on your part. Room temperature superconductors are high temperature superconductors. This makes your ad hominem somewhat sad.
No that is not so, high temperature super conductors are available now, but room temperature super conductors 'specifically' are little more than a pipe dream such as cold fusion.

No im just going on what you have posted here. Looking at that it doesn't seem remarkably impressive. Thats if it doesn't break any of the fundamental laws, which is of course suspect to begin with

Of course it's suspect. That's why I said it seemed too good to be true, and why I sought other opinions.

By what magnitude? You seem to be highly exaggerating the implications of this flying microwave oven.

If you could maintain an acceleration of 1G without expelling any mass, you could reach Mars in a matter of days, rather than months. That seems to be quite a significant advance in propulsion technology to me.

Ionized gas! You know as well as I do that for all intents and purposes it is not a chemical propellent. A standard chemical reaction such as hydrogen and oxygen would be spent in a fraction of the time in comparison.

Why is this relevant? Whether a rocket ejects gas, subatomic particles or chunks of rock, the principle is the same. If this EM engine is for real, it's entirely different and not subject to the same payload/propellant constraints.

Anyone ever hear of conservation of momentum? If it accelerates in space, to conserve momentum, something has to be going the other way.

If it merely opposes an existing force (gravity), without moving, then that's a different story. However, how that'd work is beyond me.

Imaplank
this is my last post to you. I won't waste any more time arguing with the terminally stubborn. You are ejecting chemicals that have been ionised. Understand.

And high temeperature supeconductors include high temperature superconductors. If you believe they are a pipe dream then you have researched them just about as well as you have researched everything else you post on.

I had quite a high regard for you before this little exchange. I recalled another thread where someone pointed out than when you lost an argument you took a very "well it's not important" stance. Just look what we have here.
"OK I'll give you that one. I never reference anything jsut to post with a bunch of saps."

The only person you are insulting in all of this is yourself.

The statement is actually somewhat meaningful. Chemical propellants get their energy from chemical reactions. Ion drives get their energy from electrical and/or electromagnetic actions.

Imaplank
this is my last post to you. I won't waste any more time arguing with the terminally stubborn. You are ejecting chemicals that have been ionised. Understand.

Yes chemicals that have electrons added or taken away to give a charge. Can you understand the difference between ionizing and a chemical reaction? A true chemical propellent would involve a chemical reaction.


And high temeperature supeconductors include high temperature superconductors. If you believe they are a pipe dream then you have researched them just about as well as you have researched everything else you post on.Bollocks. Roomtemperature superconductors are a pipe dream. You are on another planet in regard proper physicists if you still fail to see the distinction.


I had quite a high regard for you before this little exchange. I recalled another thread where someone pointed out than when you lost an argument you took a very "well it's not important" stance. Just look what we have here.
"OK I'll give you that one. I never reference anything jsut to post with a bunch of saps.".
Oh really, I wasn't aware anyone had any respect what so ever for me, This is the first I've heard of such and then only used as a put down.

The only person you are insulting in all of this is yourself.
No! im insulting your impertinent attacks on my comments, which I assume is merely due to a bozzo wish to put down everything I say, because I dont research a single thing I say on this forum and have made 1 or 2 errors in recall of things that are outside my study.

Anyone ever hear of conservation of momentum? If it accelerates in space, to conserve momentum, something has to be going the other way.

Well that's really the point. That's why it's so hard to believe, and so potentially ground-breaking.

Yes chemicals that have electrons added or taken away to give a charge. Can you understand the difference between ionizing and a chemical reaction? A true chemical propellent would involve a chemical reaction.

What's the difference? Whatever you throw out the back, the principle is the same. I don't understand why you're letting yourself get bogged down in pedantry about the nature of the reaction mass that this new device supposedly does away with. The whole idea is that you would not have to expel any propellant, ionized or otherwise. Not even photons.

I've read the article now. I don't think this can work....Glad we agree. Did you read my posts (four before yours) also explaining why it will not work, by a simple analogy anyone can understand?

... we can reach 3-5 degrees above zero...much better than that, I don't rembember for sure but a bout a 1000 times better. I think the best approaches use all the standard cooling mechanisms (such as a collection of atoms in a gas with a sharply defined laser frequency knocking out the "hot ones" form the group as only their Doppler shifted lines absorb, etc.) and in the final stages you turn off the external magnetic field which has been keeping their magnet monents aligned. Most of what little thermal energy is left is spent to disorganize this alignment, getting them down to less than a milla-degree or so from zero.

I dreamt about the damm thing....

and i have given it alot of thought.

it would be resonate chamber... must be.

the signal is introduced at the resonate frequency of the cavity, in this way, the wave energy we input... doesnt disapate.. but builds up...
the intensity of the wave form, rises as we add more and more energy.

the waves, bounces back and forth between to the two ends of this resonate cavity, and none of the energy is allowed to exit.

it is known that photons, do apply a push when they strike and object, but the effect is minor..

this process would send the photon back and forth between each side, and due to the shape an inbalance is created, allowed more force to apply to one side.

thus.. the Q.. i believe is the magnyfying factor of the cavity...
higher Q.. results in more intensity of the wave form in the cavity, and thus more force.. in this way,, we might generate and store.. alot.. of watts.. inside the chamber.. which than can do work, due to the force displacement.

and the reason... it would not work well for acceloration...

is we are dealing with waves.. waves which in order to apply force, must be at resonance in the cavity...
as the spaceship speeds up... accelorates... in the direction of the side with more force.... the act of moving... accelorating.. would reduce the overall force which would be applied to the higher force wall in the cavity.
thus.. more acceloration... directly causes a drop in the Q, because the waves are effected in their motion, and the cavity becomes less and less resonate, the Q drops and the over all ability of the system to apply any force is greatly diminished.

thats why they suggest using it to lift, and to make smalll motions to satalites...
since at slow velocities, and without acceloration, the Q can be at maximum, and the force output would be greatest.

fascinating stuff. I feel like building one.

-MT

much better than that, I don't rembember for sure but a bout a 1000 times better. I think the best approaches use all the standard cooling mechanisms (such as a collection of atoms in a gas with a sharply defined laser frequency knocking out the "hot ones" form the group as only their Doppler shifted lines absorb, etc.) and in the final stages you turn off the external magnetic field which has been keeping their magnet monents aligned. Most of what little thermal energy is left is spent to disorganize this alignment, getting them down to less than a milla-degree or so from zero.

yes.. Adiabatic demagnetization.
fascinating stuff.

-MT

Ionized gas! ...You do not understand how ion dirves (at least those with any significant thrust) work. Despite the name, they do not throw out ions (at least not ions of one charge only). If they did the space craft would be come oppositley charged and after traveling some distance from it they would stop and accelerate back to the ship producing no net thrust.

I do not know the details, but in some way what is ejected must be electrically neutral. Perhaps if positive ions (hydrogen nuclei or protons would be best) are thrown out you could also eject an equal nuber of electrons, but most of the electrons would soon combine with the protons to make hydrogen so effectively you are throwing out, as exhaust, fully ionized hydrogen plasma, which cools and becomes hydrogen gas, certaily a "chemical." - the most abundant one in the universe.

I have read of some systems where even before the ion beam leaves the space craft, it is neutralized to make higher than any chemical fuel specific impulse thruster, but again you are throwing out a "chemical" as your exhaust.

... this process would send the photon back and forth between each side, and due to the shape an inbalance is created, allowed more force to apply to one side. ...This is nonsense. Every thing you said about photons banging into the "properly shaped" chamber is also true it it is filled with helium gas atoms - each time they hit the wall they too apply a force to it. Do you really think some shape exists that if you fill a sealed chamber of this shape, with either photons or a gas, it will try to move due to the "internal force imbalance"? As I said, non-sense.

Send out a positively charged stream of nuclei for thrust and use electron guns to correct the imbalance.

You do not understand how ion dirves (at least those with any significant thrust) work. Despite the name, they do not throw out ions (at least not ions of one charge only). If they did the space craft would be come oppositley charged and after traveling some distance from it they would stop and accelerate back to the ship producing no net thrust.

I do not know the details, but in some way what is ejected must be electrically neutral. Perhaps if positive ions (hydrogen nuclei or protons would be best) are thrown out you could also eject an equal nuber of electrons, but most of the electrons would soon combine with the protons to make hydrogen so effectively you are throwing out, as exhaust, fully ionized hydrogen plasma, which cools and becomes hydrogen gas, certaily a "chemical." - the most abundant one in the universe.

I have read of some systems where even before the ion beam leaves the space craft, it is neutralized to make higher than any chemical fuel specific impulse thruster, but again you are throwing out a "chemical" as your exhaust.
Oh fuck off.

I am having difficulty pronouncing the title of this thread. It is pretty interesting though. :cool:

This is nonsense. Every thing you said about photons banging into the "properly shaped" chamber is also true it it is filled with helium gas atoms - each time they hit the wall they too apply a force to it. Do you really think some shape exists that if you fill a sealed chamber of this shape, with either photons or a gas, it will try to move due to the "internal force imbalance"? As I said, non-sense.


the idea that the shape of the cavity, results in inbalances of the forces involved is not my idea...

its the fundamental basis of the devices supposive operation.

the waves speed up when they enter the wide side.. and slow down when they enter the smaller side.. thus the force displacement.

its not MY idea... im just commenting on it.

and who said anything about helium?

-MT

all the starwars technology of floating vehicles could be ours.
Those vechiles already exist and have been for decades, what we're seeing in these kinds of reports is the public sector finally catching onto the technology.

and who said anything about helium?

-MT

I think the point is if this device work by momentum transfer from photons, so what about momentum xfer from a pressurised gas such as helium? Well, we know that no matter shape we make a container for a pressurised gas, it isn't going to move in one direction due to the impacts of the atoms against the walls.

So why should photons act any differently?

Conservation and Asymmetry are the biggest questions in physics. Like, why did matter not annihilate with anti-matter, why do we see more matter?

If an asymmetry can be found here, it would be deeply profound. Somehow, I think the experiment is flawed, however.

IT either works or it doesnt.... they claim it does.. lets wait and see.. and hope.

-MT

I've been following this story for a few days. I'm about 98% skeptical and 1% curious (yes... then another 1% skeptical). The only thing that actually caught my eye was that I've yet to hear an argument (other than Newton's third) on why it doesn't work. On the other hand I have no seen their proof (of their claim) that under special relativity this effect can occur.

Let me see if I can get their claims right. Please correct me if anyone else has a different understanding:

1. This is not throwing photons out the back to impart momentum on the device. They claim that NOTHING (matter or energy) will leave the device to perform the propulsion.

2. They claim that this effect would NOT work with matter because it depends on the group velocity of the microwaves in the resonating chamber (as opposed to the signal velocity).

3. Their claim is NOT that this is an empirical device with no known theoretical backing, but that this effect is predicted by special relativity (though again I have yet to see the proof).

Did I miss anything? Is anything in their NOT what others have gotten from the articles and reports?

-AntonK

Oh fuck off.Such erudition in one so young.

AntonK, everything you said matches my current understanding.

The relativity thing, if I get this right, means that they are trying to create a gradient in local space-time in the resonant cavity. The problem is that if the object moves relative to the local frame, the gradient changes from what they are trying to induce. They would have to retune and feed it more power to accelerate the vehicle.

In other words, they are trying to push against space-time itself. That's not so far-fetched. The entire mass of the universe is the backstop. You don't actually get away with this without emitting something. Hopefully the function coming out of the ass end is a lot smoother than the input, but there is a disturbance in space-time something like a radio wave.

Such erudition in one so young.

AntonK, everything you said matches my current understanding.
Yeah im very erudite ;)

No. I have re-read the original posts. He was incorrect. He got called on it. He had no response, except his traditional one of pretending disinterest. He is to be complimented for taking my ironic put down with good humour. That still fails to make him correct.

Ah. I see what you meant to mean. Yes, I had not thought about that aspect of ion engines till BillyT brought it up.

Returning more precisely to the topic, I found the New Scientist article interesting. The inventors credentials are impressive. He may just be onto something. If there is a flaw there must be one in the theory and in practice. He has, after all, measured the thrust produced by his prototype.

Well, if this is indeed predicted by special relativity, it could potentially skirt the newtonian limitation of classical action-reaction. I don't think it does (but what the hell do I know?) but wouldn't it be a kicker if there was a relativistic group velocity loophole that could be exploited?

Indeed, this is the reason for my 1% interest. Everyone keeps calling "Newton's Third!" "Newton's Third!" and normally I would agree except they have now pulled the one trump card... relativity. Relativity has a record of giving exceptions to Newton's laws. Yet again I repeat this is still my 1% curiousity, the remaining 99% is still skeptical.

-AntonK

I understand the basic concept that microwaves moving at a group velocity at, or near, 'c' will impart more momentum to the cavity surface at the 'big end' than microwaves moving at a group velocity of 1/10 'c' wrt the cavity surface at the smaller end. Newton's second law defines force as the rate of change of momentum, thus more force is imparted to the big end due to the imbalance of the forces.
What I don't understand is how the geometry of the waveguide (cavity) can change the group velocity of the microwaves as they bounce back and forth. Possibly one end could be 'in phase' and the other end 'out of phase' when the microwaves are initially injected, but how does changing the diameter of the cavity cause the group velocity of the microwaves to, presumably, all travel faster at the big end than the smaller end as they bounce back and forth? I suspect that mechanism may be above all of our levels of understanding in this forum! :p

I understand the basic concept that microwaves moving at a group velocity at, or near, 'c' will impart more momentum to the cavity surface at the 'big end' than microwaves moving at a group velocity of 1/10 'c' wrt the cavity surface at the smaller end. Newton's second law defines force as the rate of change of momentum, thus more force is imparted to the big end due to the imbalance of the forces.
What I don't understand is how the geometry of the waveguide (cavity) can change the group velocity of the microwaves as they bounce back and forth. Possibly one end could be 'in phase' and the other end 'out of phase' when the microwaves are initially injected, but how does changing the diameter of the cavity cause the group velocity of the microwaves to, presumably, all travel faster at the big end than the smaller end as they bounce back and forth? I suspect that mechanism may be above all of our levels of understanding in this forum! :p
I dont see how it would be above the forums understanding, basically the photons have to be in some way directed to a greater extent at one end of the chamber compared to the other, simple? I dont see how inteference would sway things either.
If the whole thing alludes to be beyond us, maybe it's because it's just another bit of pie in the sky like the usual free energy claims that waft by. What's the precedence for stone dropping articles in the newscientist?

From what I understand, the thrust is produced in a resonant cavity. The q-value is the number of times a wave will bounce back and forth without losing significant energy. The waves are preported to generate more momentum to the large end as the waves continually bounce back and forth, always increasing velocity as they 'bounce' from the small end towards the large end. These same waves are preported to slow as they bounce from the large end toward the smaller end, back and forth, over and over again. Always losing group velocity as they travel toward the small end, bounce, then increasing group velocity as they travel to the large end. That's what I don't understand, how do the waves increase group velocity after bouncing from the small end?? I assume it has something to do with some sort of interference pattern set up because of the geometery of the cavity, but this is more a guess than anything.

By constructing the cavities out of niobium instead of copper, then cooling to superconductor temps, the q-value is supposed to dramatically increase as it does in supercollider cavities constructed of niobium. Think of a 'perfect' mirror. Research by supercollider facilities indicate niobium-coated copper cavities are equivalent to solid niobium cavities, dramatically increasing the q-value. As a consequence, as more and more microwave radiation is fed into the cavaties over time, the force exerted on the large end is supposed to increase over time, eliminating the necessity of increasing the energy (microwave radiation) output of the waveguide.Supposedly one of the problems to be solved is to keep the cavity from distorting, or 'bending', because of the force placed upon the cavity ends. The large end would distort first, of course.

RESONANCE... the signal is fed in, at the resonate frequency of the wave motion within the cavity.
thus, with each swing of the wave energy, the input adds alittle more in perfect timing... and again and again.. always adding more than is lost in the cavity.
this is a resonate rise.

what i am curious about is the gas inside? its makeup, and whether they use any surrounding field coils in their aparatus, for that would suggest they might be utilising the gas within the chamber to applify this field energy, being ions.

this would then suggest a further means, and perhaps the secret means by which they produce the actual force on the walls.
usng the microwave field, to displace the natural pressure force in the chamber.

hummm..

-MT

MT, why do you assume there is a gas inside the enclosure? I'm not sure of course, but my impression from reading the 'popular press' releases was that there was a near vacuum inside the device, no gas, just resonating electromagnetic waves. Is some sort of gas necessary for the difference in group velocities of the microwaves wrt large and small ends?? Wouldn't a gas significantly lower the q-value in the cavities?
By the way, did you see the picture (presumably) of the prototype 'engine'? It is at the bottom of this page:
http://www.shelleys.demon.co.uk/fdec02em.htm

What's the precedence for stone dropping articles in the newscientist?I can only guess at what the phrase 'stone dropping' means. I have done so.

New Scientist is very careful in this article to neither endorse, nor condemn the idea. (On some other topics they are very happy to do one or the other.) They discuss the inventors credentials, which are rock solid, and note the opinions of others experts, which range from "pure nonsense" to "potentially exciting". All in all, it is a very balanced piece of reporting.

Yes, yes but what does 'The Sun' say about it?

I think for me personally on this issue its really less about whether or not the device actually works, so much as it is about whether or not someone has a proof which shows that special relativity naturally leads to a violation of Newton's 3rd law. I think this would be groundbreaking in itself, at which point plenty of devices would start to be built (or at least attempted to be built).

In conclusion... I really want to see that proof!

-AntonK

To Superluminal & Ophiolite:
Thanks for defending the correctness of my post correcting Imaplanck’s errors. I am glad my post also caused Ophiolite to recognize that sustained ion propulsion systems must eject neutral chemicals, not ions.

I enjoy helping others understand better and sometimes this forces me to correct errors. (I occasionally make my own - most recently in the Luminous Either thread, where I thanked for the correction at least three different times in two different posts.)

I did not respond to imaplack’s childish reply (“Oh fuck off”) as I have learned some people are either too immature to accept corrections / help, or not able to learn, so I just ignore them. Perhaps when he is more mature, he can be helped to understand physics he misunderstands.

i noted... that we cannot see the device when in proper operation on the scale.

it is hidden... and only the central part is shown to us.. out of the box.

it is not uncommon for scientists, to explain the operattion simply..
and leave out the one or two minor details which are key to making it work.
like field coils and ions.
just curious... i have nothing to base it on, other than my distrust of anyone who is revealing secrets of such worth to the public.
when doing so... it is expected.. that they will leave stuff out.

-MT

I'll believe this when I hear about the working prototype.

I just read about this in New Scientist. Even if the article had gone into detail regarding the physics, I couldn't have followed it. A brief synopsis:

A method of propulsion has apparently been devised based on resonating microwaves in a waveguide. Microwaves are created within a chamber by a magnetron. No photons need to escape from the device. Rather, the resonating radiation imparts unequal forces on the different walls of the chamber as the photons bounce back and forth, causing a net force in one direction. It seems that the engine will be at least as effective as an ion drive, with the added bonus that it needs no propellant. It may even generate enough force to accelerate itself (and a good bit more) at 1G, allowing it to hover (with some well-chosen high-temperature superconductors). Seems to good to be true to me, but what do I know?

Here's (http://www.theengineer.co.uk/Articles/Article.aspx?liArticleID=295931) somewhere to start. Please give me your opinions.

even ion engine needs xenon.

No, not according to this (IMHO) better article linked to by the first.

http://www.theengineer.co.uk/Articles/266633/Defying+gravity.htm

I feel sceptical about this, but knowing what I do about energy and matter, I'm not totally sceptical:

"Shawyer explained that if these forces were the result of a working fluid, there would merely be a mechanical strain in the waveguide walls. But as the working fluid is replaced by an electromagnetic wave at close to the speed of light, Newtonian mechanics are replaced with the special theory of relativity..."

No, not according to this (IMHO) better article linked to by the first.

http://www.theengineer.co.uk/Articles/266633/Defying+gravity.htm

I feel sceptical about this, but knowing what I do about energy and matter, I'm not totally sceptical:

"Shawyer explained that if these forces were the result of a working fluid, there would merely be a mechanical strain in the waveguide walls. But as the working fluid is replaced by an electromagnetic wave at close to the speed of light, Newtonian mechanics are replaced with the special theory of relativity..."

http://en.wikipedia.org/wiki/EmDrive

Shawyers calculations are wrong.

Maybe. I'm not saying this will work, but I'm not totally sceptical because we tend to think of momentum as a property of a moving mass. But that's not quite the right picture because a massless object like a photon has momentum. You can take a high energy photon and use it to make an electron and a positron. The energy/momentum of the photon is translated into mass, which means the conservation of momentum isn't totally rock solid.

Maybe. I'm not saying this will work, but I'm not totally sceptical because we tend to think of momentum as a property of a moving mass. But that's not quite the right picture because a massless object like a photon has momentum. You can take a high energy photon and use it to make an electron and a positron. The energy/momentum of the photon is translated into mass, which means the conservation of momentum isn't totally rock solid.


darn it....photon does have a mass. something like 10^-51 g as I calculated it once. its rest mass is 0. I used hc/delta one and some other eq.

Maybe. I'm not saying this will work, but I'm not totally sceptical because we tend to think of momentum as a property of a moving mass.

Not if you ever studied quantum mechanics you don't;

p=h/λ

But that's not quite the right picture because a massless object like a photon has momentum.

Only zero rest mass

You can take a high energy photon and use it to make an electron and a positron. The energy/momentum of the photon is translated into mass, which means the conservation of momentum isn't totally rock solid.

Conservation of energy and momentum are rock solid. The combined mass, energy, and therefore momentum of the resultant particles will add up to that of the original photon. No loss, no gain, just transfer.

Whoa, guys, I don't consider a photon to be massless. I've said it before, there's been a lot of debate in physics about mass, and I take the view that something with energy has mass, and rest mass is the special case. Look up pair production and on-shell.

http://en.wikipedia.org/wiki/Pair_production

And Planck's constant.

http://en.wikipedia.org/wiki/Planck's_constant

THE PROBLEM IS.... THE ENGINEERS... probuly left out some detials...

if they dont... the whole idea would get stollen real quick.

-MT

Conservation of energy and momentum are rock solid.
You see, that doesn't seem to apply to the Universe as a whole. The Universe is not only expanding, but the expansion is accelerating; the energy for this expansion apparently comes from nowhere. And how the galaxies which are expanding away from us at an accelerating rate have conserved momentum is another matter. Not to menton the thorny question of where the matter and energy of the the Universe as a whole came from in the first place.

I think you will probably find that energy and momentum are conserved locally, but not on a universal scale; which may, just may, open the door to some bizarre Alcubierre-like reactionless drive. But Shawyer's mechanism almost certainly isn't such a beast.

You see, that doesn't seem to apply to the Universe as a whole. The Universe is not only expanding, but the expansion is accelerating; the energy for this expansion apparently comes from nowhere.

Well, no, we just don't know where it comes from, or whether our observations on the matter are leading us to the right conclusions. Everything points to conservation of momentum and energy being correct, so don't let one anomaly ruin the good data.


And how the galaxies which are expanding away from us at an accelerating rate have conserved momentum is another matter.

What's the question here? If they are accelerating, something is fuelling that. We just don't know what it is, but there is no reason to speculate that is violates current understanding.

Not to menton the thorny question of where the matter and energy of the the Universe as a whole came from in the first place.

If you sum it all up, I rather think it will add up to zero, all things considered. So what do you think actually exists?

Probably not, but let's leave the door open just a tad. Search google on "Momentum is not conserved".

http://www.google.co.uk/search?hl=en&q=%22momentum+is+not+conserved%22&meta=

The momentum of a body isn't necessarily conserved, but the momentum of the system is. So if you can reach out of your "body" into the system, well, let's just say there are opportunities.

I quite liked this:

http://www.tompotter.us/momentum.html

"Although it is commonly believed that the kinetic energy and momentum, of a body, are conserved, the fact is that neither of these quantities is conserved. What is conserved in interactions is action. As a case in point, the momentum and the velocity of satellites in elliptical orbits are constantly changing. What remains constant ( Is conserved) is the angular momentum, which is the product of momentum and distance. Although the kinetic energy and momentum of a body is not conserved, the kinetic energy and momentum of a system is conserved, as the other bodies in the system react equal and opposite to each other. For example, if the momentum of a satellite is changes, the momentum of the central body must also change an equal and opposite amount.

It can be shown mathematically, that if space is isotropic ( The same in every direction.) that angular momentum is conserved, and if space is homogenous ( The same everywhere.) that momentum is conserved. Apparently space is isotropic as angular momentum is always conserved, but the fact that momentum is not conserved indicates that space is not homogenous. As space is basically time intervals, what this indicates is that the spaces ( Time intervals) in a stable system can vary, as long as the velocities vary is such as way as to keep the product of momentum and velocity constant. In other words, the time intervals ( Space), between a body and the center of gravity of the system it is associated with, can vary, even in a stable system...

Whoa, guys, I don't consider a photon to be massless.

Then, you don't agree with observations and the results of experiments? What exactly don't you agree?

I've said it before, there's been a lot of debate in physics about mass

Only amongst those who don't understand physics.

Well, no, we just don't know where it comes from, or whether our observations on the matter are leading us to the right conclusions. Everything points to conservation of momentum and energy being correct, so don't let one anomaly ruin the good data.
Agreed; however that one anomaly turns out to be the Universe itself, which is a bit difficult to explain away at the moment.
If you sum it all up, I rather think it will add up to zero, all things considered. So what do you think actually exists?
Right; we can look at the expanding universe as being homogenous, and as long as the momentum balances overall momentum is conserved.
Just like in any explosion.

But the homogenous nature of the Universe is a mystery, especially as the different parts of the universe cannot communicate with each other. Basically- how can the universe be homogenous when parts of it are beyond the c-horizon of other parts? As a whole, the universe is not a closed system; therefore all conservation laws need not apply.

There are likely a thousand workable ways to give you a push in space. We are in need right now of just one, easy to store (fuel) for the long trips thru space. The one that gives us the most bang for the buck will do. There can be some very interesting interchanges between energy and mater. Mater being a very highly condensed form of energy, it can be expanded to huge areas and massive thrust, all from a simple energy wave. This in part is neclear power.

Then, you don't agree with observations and the results of experiments? What exactly don't you agree?

Oh I do so. You don't. Show me a photon at rest and I'll agree with your assertion that it has zero mass. My preferred view is that both mass and energy contribute to gravity, a photon has energy, so it contributes to gravity, so we can view that energy as mass. Now we can talk sensibly about the best definition of mass as regards rest mass v relativistic mass...

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

"It might be thought that it would be better to regard the relativistic mass as the actual mass of photons and light, instead of invariant mass. We could then consistently talk about the light having mass independently of whether or not it is contained. If relativistic mass is used for all objects then mass is conserved and the mass of an object is the sum of the masses of its part. However, modern usage defines mass as the invariant mass of an object mainly because the invariant mass is more useful when doing any kind of calculation. In this case mass is not conserved and the mass of an object is not the sum of the masses of its parts. For example the mass of a box of light is more than the mass of the box and the sum of the masses of the photons (the latter being zero). Relativistic mass is equivalent to energy so it is a redundant concept. In the modern view mass is not equivalent to energy. It is just that part of the energy of a body which is not kinetic energy. Mass is independent of velocity whereas energy is not...

...but please don't try to pretend that this is not a valid debate via facile attempts to discredit.


Only amongst those who don't understand physics. Yeah, too right.

Oh I do so. You don't. Show me a photon at rest and I'll agree with your assertion that it has zero mass.

Photons are never 'at rest.'

My preferred view is that both mass and energy contribute to gravity, a photon has energy, so it contributes to gravity, so we can view that energy as mass.

Your 'preferred view' is exactly that, regardless of it not agreeing with observation and experiment.

Now we can talk sensibly about the best definition of mass as regards rest mass v relativistic mass...

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

"It might be thought that it would be better to regard the relativistic mass as the actual mass of photons and light, instead of invariant mass. We could then consistently talk about the light having mass independently of whether or not it is contained. If relativistic mass is used for all objects then mass is conserved and the mass of an object is the sum of the masses of its part. However, modern usage defines mass as the invariant mass of an object mainly because the invariant mass is more useful when doing any kind of calculation. In this case mass is not conserved and the mass of an object is not the sum of the masses of its parts. For example the mass of a box of light is more than the mass of the box and the sum of the masses of the photons (the latter being zero). Relativistic mass is equivalent to energy so it is a redundant concept. In the modern view mass is not equivalent to energy. It is just that part of the energy of a body which is not kinetic energy. Mass is independent of velocity whereas energy is not...

Yeah, yeah, whatever. Observe the text in red and conduct an experiment for yourself:

"It might be thought that it would be better to regard the relativistic mass as the actual mass of photons and light, instead of invariant mass. We could then consistently talk about the light having mass independently of whether or not it is contained. If relativistic mass is used for all objects then mass is conserved and the mass of an object is the sum of the masses of its part. However, modern usage defines mass as the invariant mass of an object mainly because the invariant mass is more useful when doing any kind of calculation. In this case mass is not conserved and the mass of an object is not the sum of the masses of its parts. For example the mass of a box of light is more than the mass of the box and the sum of the masses of the photons (the latter being zero). Relativistic mass is equivalent to energy so it is a redundant concept. In the modern view mass is not equivalent to energy. It is just that part of the energy of a body which is not kinetic energy. Mass is independent of velocity whereas energy is not...

And whilst you're not remotely interested, this is Mass Explained: http://www.sciforums.com/showthread.php?t=61557&highlight=mass+explained

Yeah, yeah, whatever. Observe the text in red and conduct an experiment for yourself:

the mass of a box of light is more than the mass of the box and the sum of the masses of the photons (the latter being zero).

Since you point that out, please explain why YOU think the total sum is more than the sum of the individual parts?

And please stop posting a link to your ridiculous thread.

Huh? I don't think the total sum is more than the sum of the individual parts. If a box of light has a mass of 2 grams and the box has a mass of 1 gram, what I'm saying that the light has a mass of 1 gram. I explained all this in MASS EXPLAINED. You ask me to explain, but at the same time you don't want me to, because you'd rather stick with your 1 + 0 = 2.

The point being that because I understand mass and energy, I don't totally rule out "propellantless propulsion" even though I feel sceptical about SPR.

Huh? I don't think the total sum is more than the sum of the individual parts. If a box of light has a mass of 2 grams and the box has a mass of 1 gram, what I'm saying that the light has a mass of 1 gram. I explained all this in MASS EXPLAINED. You ask me to explain, but at the same time you don't want me to, because you'd rather stick with your 1 + 0 = 2.

The point being that because I understand mass and energy

Since you refuse to learn anything and wish to stick to your silly pet theories, there's really nothing more anyone can say. At the very least, read a book someday.

LOL, at the very least, answer this question:

Q: If a box of light has a mass of 2 grams and the box has a mass of 1 gram, what is the mass of the light?

Don't you get it yet? I understand mass. You don't want to. And what's sad, is that you'd rather pour bile and insults.

LOL, at the very least, answer this question:

Q: If a box of light has a mass of 2 grams and the box has a mass of 1 gram, what is the mass of the light?

As was said, zero.

I understand mass.

No, you don't.

You don't want to.

I don't want to follow your silly pet theory, if that's what you mean.

And what's sad, is that you'd rather pour bile and insults.

They're not insults, they're observations.

I've read all that Superluminal. Here's another one. Read about the box of light having more mass than its parts.

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

I've read all that Superluminal. Here's another one. Read about the box of light having more mass than its parts.

http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html

First, there is this gedanken with explanation:

However, if light is trapped in a box with perfect mirrors so the photons are continually reflected back and forth in the box, then the total momentum is zero in the box's frame of reference but the energy is not. Therefore the light adds a small contribution to the mass of the box. This could be measured - in principle at least - either by an increase in inertia when the box is slowly accelerated or by an increase in its gravitational pull. You might say that the light in the box has mass but it would be more correct to say that the light contributes to the total mass of the box of light.

... followed closely with this:

"You should not use this to justify the statement that light has mass in general."

Quotes Taken from Link:

"The photon is a massless particle."
Actually, the 'idea' of a particle is something we attribute to a photon. It is also very convienent and correct to treat light like a wave in some circumstances. Hence, Wave-Particle Duality.

Just thought Id throw that in there.

Furthermore, RELAX. Things can be lost in reading words vs a discussion, so its best to explain everything very, very carefully.

And with relativity and light, remember reference frames. If you forget about those, its all meaningless.

Tristan

Thank you Tristan.

Here's a link about particle creation:

http://galileo.phys.virginia.edu/classes/252/particle_creation.html

"The neutral pion mass is 135 MeV, the charged pions have mass 140 MeV, where we follow standard high energy practice in calling mc2 the "mass", since this is the energy equivalent, and hence the energy which, on creation of the particle in a collision, is taken from kinetic energy and stored in mass..".

In simple terms this is putting light into a box, albeit without the box. Understanding this is crucial to any serious discussion about "propellantless propulsion".

In simple terms this is putting light into a box, albeit without the box. Understanding this is crucial to any serious discussion about "propellantless propulsion".

But, do YOU actually understand that photons have no mass?

Let's try to be a little more precise shall we?

a) rest mass by definition does not apply to a photon.
b) does not apply is not the same as is zero.
c) a photon has relativistic mass.
d) rest mass v relativistic mass has been an ongoing debate in physics
e) I understand mass, I can explain it.
f) you have no rational argument to counter MASS EXPLAINED
f) An understanding of mass is relevant to "propellantless propulsion"

http://www.sciforums.com/showthread.php?t=61557&highlight=mass+explained

Now, can we get on please?

If we look at the Baez article, we can see that the debate revolves around terminology:

http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

The old definition of mass, called "relativistic mass" assigns a mass to a particle proportional to its total energy E, and involved the speed of light, c, in the proportionality constant: m = E / c 2.

The modern definition assigns every object just one mass, an invariant quantity that does not depend on velocity. This is given by m = E0 / c 2, where E0 is the total energy of that object at rest... Note, by the way, that using the standard definition of mass, the equation E = m c 2 is not correct. Using the standard definition, the relation between the mass and energy of an object can be written as... E 2 = m 2 c 4 + p 2 c 2

In one sense, any definition is just a matter of convention. In practice, though, physicists now use this definition because it is much more convenient. The "relativistic mass" of an object is really just the same as its energy, and there isn't any reason to have another word for energy: "energy" is a perfectly good word. The mass of an object, though, is a fundamental and invariant property, and one for which we do need a word...

I understand energy and mass, I know how energy equates to relativistic mass and can be tied up as rest mass, how an object is turned into another object and how momentum becomes inertia. It isn't rocket science, after all pair production tells us all that rest mass is not fundamental. I know how the two portions of E 2 = m 2 c 4 + p 2 c 2 are bridged back to E = m c 2, and it pains me to see the confusion created by "modern convenience" coupled with dogmatic hostility.

c) a photon has relativistic mass.

You still don't get it. Mind like a steel trap, nothing gets in.

d) rest mass v relativistic mass has been an ongoing debate in physics

No, a debate for people like you who don't understand physics.

e) I understand mass, I can explain it.

You imagine it, from the same place your explanations are derived.

f) you have no rational argument to counter MASS EXPLAINED

Rational arguments are not used to explain gibberish.

If we look at the Baez article, we can see that the debate revolves around terminology:

No, what we can see is that you are unable to comprehend it.

I understand energy and mass, it pains me to see the confusion created by "modern convenience" coupled with dogmatic hostility.

You think that's painful? :rolleyes:

Sigh, do you ever contribute anything apart from insults?

No, a debate for people like you who don't understand physics.


Facts speak against you.
a limit to mass of photon mass, less than 10-51 grams has been established.

http://www.aip.org/pnu/2003/split/625-2.html


and yes it has been a debate for years.

http://www.ibiblio.org/lunar/school/library/massphot.html

Sigh, do you ever contribute anything apart from insults?

Just stating the facts, ma'am.

Facts speak against you.
a limit to mass of photon mass, less than 10-51 grams has been established.

Really? Tell us exactly what that means, Einstein? How do you interpret that article?

and yes it has been a debate for years.

Uhuh... :rolleyes:

Really? Tell us exactly what that means, Einstein? How do you interpret that article?


My name is not Einstein, its Ivan aka draqon.

I interpret the article that the mass of photon does have a mass and it is below that value they specified.

I interpret the article that the mass of photon does have a mass and it is below that value they specified.

Try this interpretation: The photon has no mass, and we have proven that this conjecture is true to with 10-51 grams (i.e., to within an incredibly small experimental uncertainty).

Try this interpretation: The photon has no mass, and we have proven that this conjecture is true to with 10-51 grams (i.e., to within an incredibly small experimental uncertainty).

doesnt mean it doesnt have mass. I mean think of all the neutrino particles passing through Earth...and fool would say they have no mass...yet there are Japanese and American neutrino capturing heavy water facilities which do trap neutrinos and are able to study these particles. When it comes to numbers...these so called "massless" particles...actually have some mass.

doesnt mean it doesnt have mass. I mean think of all the neutrino particles passing through Earth...and fool would say they have no mass...yet there are Japanese and American neutrino capturing heavy water facilities which do trap neutrinos and are able to study these particles. When it comes to numbers...these so called "massless" particles...actually have some mass.

Neutrinos are fermions and are not considered massless, unlike photons.

Neutrinos are fermions and are not considered massless, unlike photons.

...allrighty than. Why would solar sails work than? huh? :cool: Because space experiments have shown that pressure from photons accelerates the solar sails.

I understand ducks. If it walks like a duck and quacks like a duck... But oh no, it clearly isn't a duck because Q defines ducks as being yellow and made out of rubber.

I understand mass too. And some people who don't, just don't want to. It's not as if they study my explanation and point out where I'm mistaken. They just don't want to know, and they use cheapshot insults to try and cover this up. It vexes me that people who pretend to be rational open-minded scientists can behave this way.

You will notice that light from the sun can have a pushing effect. This tells you off the bat that energy can be used as a system of repulsion.

With matter as a condensed form of energy, matter can be expanded to make large amounts of energy. Just how much expansion you get out of it is how good your propulsion is.

At the moment, we have a very low expansion rate. Rocket fuel just will not cut it.

The form of energy that is produced is less important for space travel. So long as you direct the output you will get thrust. The problem of propulsion is not what works as thrust, that is too easy, it is meaningful expansion of a fuel that can get you over long distances and is storable in usable amounts.

Farsight:

You understand the equation

E^2 = m^2 c^4 + p^2 c^2 = (mc^2)^2 + (pc)^2

right?

Now. Apply that to a photon for me.

In particular, tell me what value you use for "m" in that equation, when you're dealing with a photon. And do you always use the same value of "m", or not?

No problem James. If we look at the equation what we're seeing is a rest mass component, plus a velocity component:

E^2 = (mc^2)^2 + (pc)^2

For a photon the rest mass m is taken to be zero, so we drop the first portion:

E^2 = (pc)^2

We can simplify this to:

E = pc

Then with the loss of a little momentum we can use our photon in pair production to create an electron and a positron, which means pc is now reconfigured to the first term:

E = mc^2

The rest mass is nowadays considered to be simply mass, by definition, though you will sometimes hear the phrase "invariant mass". It is therefore separated from "relativistic mass". IMHO this tends to act as a barrier to any consideration of the localisation of momentum into inertia.

...allrighty than. Why would solar sails work than? huh? :cool: Because space experiments have shown that pressure from photons accelerates the solar sails.

Photons are made of energy, which has momentum, which is transferred to the sails, hence accelerates them. No mass required.

For a photon the rest mass m is taken to be zero

That's what we've been trying to tell you all along.

The rest mass is nowadays considered to be simply mass, by definition, though you will sometimes hear the phrase "invariant mass". It is therefore separated from "relativistic mass". IMHO this tends to act as a barrier to any consideration of the localisation of momentum into inertia.

So, your problem is understanding 'relativistic mass?'

I understand ducks. If it walks like a duck and quacks like a duck... But oh no, it clearly isn't a duck because Q defines ducks as being yellow and made out of rubber.

How is lying going to help your argument?

I understand mass too. And some people who don't, just don't want to. It's not as if they study my explanation and point out where I'm mistaken. They just don't want to know, and they use cheapshot insults to try and cover this up. It vexes me that people who pretend to be rational open-minded scientists can behave this way.

A typical woo-woo complaint.

I understand mass too. And some people who don't, just don't want to.


Then publish that paper and wait for the Nobel prize, because nobody, and I really mean nobody, understands mass.

Then publish that paper and wait for the Nobel prize, because nobody, and I really mean nobody, understands mass.

God.

Then publish that paper and wait for the Nobel prize, because nobody, and I really mean nobody, understands mass.

LOL. I do. And you don't want to.

How is lying going to help your argument?

A typical woo-woo complaint.

Did you miss what I said there Q? Here's a reminder:

I understand mass. And some people who don't, just don't want to. It's not as if they study my explanation and point out where I'm mistaken. They just don't want to know, and they use cheapshot insults to try and cover this up. It vexes me that people who pretend to be rational open-minded scientists can behave this way.

All: I'm on holiday for a week, and might be out of contact for the duration.

No problem James. ... Then with the loss of a little momentum we can use our photon in pair production to create an electron and a positron, which means pc is now reconfigured to the first term:
E = mc^2 ...Not much of an answer to James' question {what is photon's mass you assume?} as the photon can create many different pairs. Easier would be a muon pair, harder would be a proton/ antiproton pair. If it has lots of enegy, the photon may continue to "live" and create other pairs by lossing just the required ENERGY, NOT MASS, of the pair when doing so. Please try again.

It was a plenty fine answer, and you're just nitpicking. An electron has energy of 511keV as does a positron, so you need to start with a gamma photon of 1022keV. Just a tad more in fact.

If you want to understand mass, read MASS EXPLAINED:

http://www.sciforums.com/showthread.php?t=61557.

If you don't, don't. No problem.

If you do, thank you. If you find my explanation wanting and can point out the flaw in my explanation, please accept my grovelling humble apologies in advance. But if you can't or won't, don't try to make up for it by telling me I don't understand mass. That just isn't scientific.

... don't try to make up for it by telling me I don't understand mass. That just isn't scientific.I did not tell you that (although it is obviously true). What I said was you were not answering James's question as there are many differ masses that the pair produced could have produced. Way do you select the electron positron pair mass to assign to the photon (instead of the easier muon pair or harder proton pair)? I.e. Why not any of the three different muons and it anti-muon for a lower mass? Why not the proton and the anti-proton masses?

YOU HAVE NO THEORY (Theories require backing by experiments and mathematical predictions.)

YOU HAVE NOT answered either James or my simple question.

Why should we read long crackpot garbage when you can not even answer simple questions?

Farsight:

The rest mass is nowadays considered to be simply mass, by definition

Right. Then what's all the argument about?

You seem to agree that the rest mass of a photon is zero. Therefore, the statement that photons have no mass ought to be uncontroversial for you.

Or am I missing something?

Did you miss what I said there Q? Here's a reminder:

I understand mass. And some people who don't, just don't want to. It's not as if they study my explanation and point out where I'm mistaken. They just don't want to know, and they use cheapshot insults to try and cover this up. It vexes me that people who pretend to be rational open-minded scientists can behave this way.

Nope, didn't miss it. Lets' count the ways in which you follow the woo-woo credo:

"Try to answer as few direct questions as possible. Always obfuscate and try to sound learned. Mimic Richard Hoagland's style and you'll go far.

If you're cornered and asked for proof of something, always tell the person that they "can't disprove" your claims. Many of them will just walk away shaking their heads, which of course means they agree with you. A side-to-side head shake could be the same as a vertical nod. Anything is possible, after all.

Always claim that the other guy is "closed-minded" and that you're as free-thinking as a newborn baby. Other woo-woos love the concept of "open-mindedness" and will take you into their inner circle without question. They have no tolerance for those "mean old nasty" types who demand evidence for everything.

Refer to anyone who does not immediately agree with you as being uneducated on the matter, lacking in important information, or just plain too stupid to understand your magnificent statements.

When all else fails.... SPAM SPAM SPAM SPAM SPAM.....

Keep trotting out the one "respectable" scientist who might possibly have said something that could be construed as perhaps giving a hint that it may theoretically support your position. Even better if said scientist has said it outright. Ignore all complaints that the work is 50 years out of date, the scientist has no experience in the field in question or that other experts in the same field think said scientist is a complete loony (and they can prove it, too).

Whenever you read something on the Internet, re-post it as fact.
Never bother to do even basic research into the matter."

http://www.watchingyou.com/woowoo.html

LOL. I do. And you don't want to.

No, you have a bucketload of arrogance, and very little understanding.

But here's a few questions for you. If you understand mass, how can we counteract it's effects? IE, where's the anti-gravity mechanism? What actually causes mass to attract? Are there gravitons? For someone with all the answers like you, these should be simple questions.

I see a future in propulsion using electro-magnetic engines because electricity is easy to come by.

Storing fuel for chemical engines is troublesome for efficiency reasons. I don't have any delusions of electricity out doing chemical by thrust. But electricity can be stored with easy. It can also be used with very highly condensible fuels (like those that can be turned into a gas or plasma) that can used with as an exciter. The end result is a weak propellant that has the ability to be fired for extraordinary amounts of time and thus outdo it's chemical counter part.

Anyway, I have a hunch that there is a way to get allot more power out of this universe then by anything we have thought of yet. And for propulsion, a better rocket fuel would be a nice place to start.

Getting this resolved and getting people into space would be nice. The first money making project of space can be to empty all those lines of people that gather just before a Star Wars movie. Get them off my planet! :D And they can have fun while doing it too.

No, you have a bucketload of arrogance, and very little understanding.

But here's a few questions for you. If you understand mass, how can we counteract it's effects? IE, where's the anti-gravity mechanism? What actually causes mass to attract? Are there gravitons? For someone with all the answers like you, these should be simple questions.

Let's see shall we? I'm only too happy to answer your questions, and any more you'd like to ask:

I can't tell you how to contrive an anti-gravity mechanism. LOL, but if I could, I wouldn't.

What causes masses to attract is a local tension gradient that balances matter/energy stress. It's expressed as a change in c, but you can't measure it directly.

No, there are no gravitons, not as "particles" flying between masses. But since gravity is related to say electromagnetism where there are photons, it's not quite correct to say there are no gravity quanta.

BillyT: I selected the electron/positron pair to keep things simple. Sure I haven't got a "theory". But what I have got is a layman's essay and an understanding. And what simple question haven't I answered? I take great pride in my honesty and never shirk questions. But when you defend your blinkered ignorance by calling my essay crackpot I take offence.

James: What the argument is about is whether propellantless propulsion is possible. I think it might be, because energy contributes to gravity, and by considering mass to be relativistic mass rather than rest mass we might contrive propellantless propulsion - where the momentum of an extended system is conserved, but the momentum within a given object is not.

Q: let me know when you've got something to contribute other than insults.

I take great pride in my honesty and never shirk questions. But when you defend your blinkered ignorance by calling my essay crackpot I take offence.

A rose is still a rose.

Q: let me know when you've got something to contribute other than insults.

When will you contribute something other than gibberish?

Can I reiterate that if anybody has any questions of me, I'll try to answer them to the best of my abilities. And if you think I've ducked some issue, please don't hesitate to point it out.

it's not quite correct to say there are no gravity quanta.

So are you saying there are gravity quanta?

Because if so, you have contradicted yourself somewhat, saying there are no gravitons, because thanks to particle wave duality, you can't have one, without the other.

Care to clarify your position?

Sure.

If we consider energy to be a volume of spatial stress, and if we consider a photon to be a somewhat localised quantum of that energy, and if we consider gravity to be a balancing tension extending out into the surrounding space, then adding one extra photon means we add one extra quantum of energy to the "system". The gravity of that system will increase by a complimentary amount. However we will not find one extra graviton in any given location.

There's a lot of ifs in the above, but I hope it explains my thoughts adequately.

Cool article, thanks.

Didn't Tesla work on this shit back in the day?

What is this woo woo BS
just one person climbing on the back of another
Grow up all of you
Science is fantasy, and yes you add in observations... which are interpreted by a biased mind
and yes the whole structure of science builds, often on foundations of permafrost...

LOL you guys have no idea about science, let alone discussion

Discussion should be about any aspect of reality, it is not up to the proponant to fill in the gaps of their intuitive fantasy framework

If that was so science would never be where it is today,, and the greeks might as well have never been
No it is your job to bring in observations and correlate them in a way to debunk or at the least to show where the discrepencies lay.

Science is full of cracks, and the way forward is to expose these cracks, not plaster them up with your stupid claims of woo-woo from a pulpit of superiour fantasy, you call established knowledge

Guys, you call woo woo and I know who is not a scientist..... and I am sick to death of such people being in positions of moderation
You destroy discussion, you destroy innovation and you set science into a religious dogma

I will say it again GROW UP

Guys, you call woo woo and I know who is not a scientist..... and I am sick to death of such people being in positions of moderation
You destroy discussion, you destroy innovation and you set science into a religious dogma

I will say it again GROW UP

Show us the formulae, and we will shut up.

URI

There is nothing wrong with asking for the facts. Anyone that goes too far from the real world is going to be useless to all.

Direct your efforts at how your ideas can be made real. Not at getting rid of those that think they know better than you what is possible and what is not. You will find that this can win over anyone that challenges you as you are not fighting them. Thus it is hard for them to fight you.

Expanding upon established research in the physics of particles in a magnetic field, Dr. Peck describes how a spacecraft can be made to accelerate in a direction perpendicular to a magnetic field, as do all electrostatically charged objects to some degree.

Evidence of Lorentz forces in action appears, for example, in new images from NASA's Cassini spacecraft: the rings of Jupiter and Saturn contain dust particles whose orbits are governed by these forces. Dr. Peck proposes to exploit this natural behavior on a larger scale, allowing spacecraft to be propelled by the same principle.

Here is how a spacecraft taking advantage of Lorentz-actuated forces would work. Spacecraft naturally acquire a charge as they travel through a planetary body's surrounding plasma, but the charge is typically not very high.

Thus, to achieve a useful force, it must boost its charge by emitting charged particles (such as ions or electrons) via a high-energy beam. As a suitably "charged" Lorentz-enabled spacecraft orbits a planet, the planetary magnetic field naturally deflects the spacecraft's path toward a direction perpendicular to the magnetic field lines, which also affects the spacecraft's velocity.

It does this in much the same way as electromagnetic forces steer the electron beam in the old cathode-ray TV sets to paint the picture on a TV screen. The effect is greater near the north and south poles where the magnetic field is denser. Since planetary magnetic fields rotate with the planet, that perpendicular acceleration can lie in a direction that adds energy to the spacecraft's orbit.

The results are remarkable: without propellant, a spacecraft can achieve new earth orbits, cancel out atmospheric drag, and establish new stable satellite formations. This means of propulsion can allow freight and passengers to be transported throughout the solar system, using planetary magnetic fields as stepping stones from planet to planet.
http://www.spacedaily.com/reports/Cornell_To_Study_Planetary_Magnetic_Fields_Propuls ion_Research_Under_NASA_Grant_999.html

>> Here is how a spacecraft taking advantage of Lorentz-actuated forces would work. Spacecraft naturally acquire a charge as they travel through a planetary body's surrounding plasma, but the charge is typically not very high. Thus, to achieve a useful force, it must boost its charge by emitting charged particles (such as ions or electrons) via a high-energy beam. As a suitably "charged" Lorentz-enabled spacecraft orbits a planet, the planetary magnetic field naturally deflects the spacecraft's path toward a direction perpendicular to the magnetic field lines, which also affects the spacecraft's velocity.

It does this in much the same way as electromagnetic forces steer the electron beam in the old cathode-ray TV sets to paint the picture on a TV screen. The effect is greater near the north and south poles where the magnetic field is denser. Since planetary magnetic fields rotate with the planet, that perpendicular acceleration can lie in a direction that adds energy to the spacecraft's orbit. The results are remarkable: without propellant, a spacecraft can achieve new earth orbits, cancel out atmospheric drag, and establish new stable satellite formations. This means of propulsion can allow freight and passengers to be transported throughout the solar system, using planetary magnetic fields as stepping stones from planet to planet. >>

Now there is a start... ESG theory describes it all. The quest a true space drive.

But of course useless without a propellant-less inertial drive.

Actually you don't even need that. There was an article about NASA kind of slingshotting around the solar system about a year ago in New Scientist.

http://www.newscientist.com/article/mg18925441.300.html

Sorry, that's just a stub, maybe this is better:

http://www.esm.vt.edu/~sdross/superhighway/

http://www.esm.vt.edu/~sdross/images/superhighway_med.jpg

It's a slow way to get around though.

Travelling via orbits is unbelievably wasteful
travel 10 billion km to go 100,000......

But that is a nice picture, because in ESG theory there are slipstreams between spin systems where travel velocities will be greatly enhanced. Mapping these slipstreams would be an explorers task so they could be entered in the star maps.
yes a type of superhighway, but not orbital dynamics.

It sure is wasteful in terms of time, URI. But cheap in terms of propellant.

What's ESG theory?

I don't know anything about orbital dynamics or what this method is called. OK guilty your honour: slingshot was the wrong word to use.