QuoteEM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.I am NOT impressed by this site. It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force. Newton and all have NO problem with a closed system measuring rotation rate. No need to introduce Special Theory effects to explain this. Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.However I do hope I am wrong and they produce a really nice rocket engine someday. I for one will not be investing my money in this technology.Danny DegerP.S. Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket. This would make the device not violate the law of the conservation of momentum.
EM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.
"Anyone interested in doing this work is invited to do so." Certainly, but that's also like saying, "anyone who wants to build a hydrogen fueled automobile is free to do so." Easy to say and fairly hard to do.Anyhow, about the gold leaf. you can levitate a ping pong ball in the air from the other end of a vacuum cleaner. In order to propel something, there has to be a directional force somewhere. If we're using the universe to push against that gold leaf, then so be it. Point is, if this is going to be a rocket, something needs to be pushed. Yeah, levitating itself around the lab would be a very impressive display, sure to get investor dollars. But I think an easier display is to demonstrate lifting something against the pull of Earth's gravity.Am I correct that the device doesn't have enough thrust to escape Earth's gravity? But it has some thrust. Maybe not levitate a gold leaf, but push against a balance beam, then. Something that the guy with money can see.I also don't understand why he doesn't seek funding. Either the science hasn't yet been proved, or he's trying to get the big bucks associated with the patent. I have argued for altruism on this site, and have been ridiculed. I would have a hard time believing that his is an altruistic exercise.
QuoteQuoteEM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.I am NOT impressed by this site. It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force. Newton and all have NO problem with a closed system measuring rotation rate. No need to introduce Special Theory effects to explain this. Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.However I do hope I am wrong and they produce a really nice rocket engine someday. I for one will not be investing my money in this technology.Danny DegerP.S. Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket. This would make the device not violate the law of the conservation of momentum.I took me a while to understand how it works. There is a basic property of a waveguide that describes how the group velocity of a wave changes as the size of the waveguide changes. For the em-drive it is this that creates the force imbalance on the end walls of the cavity. In terms of momentum, if there are two equal masses and the total momentum p=p1-p2 then p is non zero when the velocities of the particle colliding at each end of the waveguide differ. The slope of the walls of the cavity ensure the collisions with the walls along the length result in a nonlinear force ie: the differing group velocities along the length of the sloping cavity ensure the particles don't just bounce around inside the cavity canceling each others forces totally out. One uses the law of relativistic velocity addition to see that there is forward motion when the thruster is viewed by an outside observer (thus an open system).To illustrate:If one fires two opposing canons within a closed box the impact of the canonballs against the walls will cancel out to result in zero motion. If either the velocity or the mass of one of the balls changes en-route to the wall then the impacts will not cancel out and there will be motion. The trick then is to deal with the lost mass or velocity. It has to have gone somewhere. From the point of view of momentum; The em-drive looks at the change in velocity whereas the woodward drive looks at the change in mass. The both deal with the imbalance in different ways. EM-drive uses the properties of waveguides and relativity whereas woodward's drive uses machian mass fluctuations and a rectifier.When one accounts for the energy absorbed into the system to create the motion then one retains conversation of energy. Same for momentum.So I think I understand. Took me a while but I think I'm there. And it is basic physics! It USES newton laws. It just needed a different perspective.
"There is a basic property of a waveguide that describes how the group velocity of a wave changes as the size of the waveguide changes."Very interesting. Could you explain a little more for us how this change in group velocity can explain a change in momentum without violating conservation? I think this is the sticky point people seem to disagree with Shawyer on.
"In my example - the momentum "mysteriously" lost by one canonball (due to change in velocity in the waveguide) is converted equally into the momentum gained by the system, thus conserving momentum."Well, as I'm not a physicist I'll leave detailed analysis alone, but I have to say, I'm anything but convinced. You can do the math but intuition tells me this is wrong. If you fire one cannonball right and another left, and mysteriously drop the velocity to the right, you would have to conserve by somehow finding momentum to the right. But instead, what you get is net force to the left. I think that's wrong. Sounds like someone got a sign wrong somewhere. . .
Seems like small thrusts are possible. What you need on a long interstellar flight. Pico-Newtons aren't very much. About the power supply: it's good that it's potentially simple. I have an old tube Mac that probably would be too heavy to levitate itself, but I bet it could climb up a cable to the Moon.Anyhow, the power supply so far is attached to a cable, and the demonstrated force experiments are more like a balance beam, I gather.I like the idea of research for it's own sake, and it's true that investors frown upon an inventor changing his direction without their assent. But I still don't get it. Is this technology at the proof of concep phase?Now to read IAC- 08 – C4.4.7.
I'll try to come up with a better illustration of the concept. It seems understandable to me but I've worked thru the equations. My intuition tells me it is correct because of this. But until one clicks ones intuition will never accept it.Gimme a couple of days.For those uncertain as to why the forces on each end of the waveguide differ - consider a tapered pipe with water flowing thru it. the water goes faster the smaller the pipe becomes. ie, the same mass moves thru at a higher speed in the smaller pipe than the larger one. This is analagous to the group velocity of light in a waveguide.Faster moving water impacts a wall with higher momentum than slow moving water. One should thus easily see that the forces on each end of the waveguide are different. That part of the illustration is easy enough. The rest is hard as it involves relativity and the concept of an open system.Let me think on it.
Quote from: Patchouli on 04/15/2009 03:25 amIt would be interesting if the device actually works but it also appears to be a relativity low thrust device like an ion rocket.Even if it does work you'll still need a conventional rocket or RLV to get a vehicle equipped with it into orbit.Patchouli:You didn't read or at least understand my scaling slide that I appended earlier. Let me summarize it here again for you. There are no currently known theoretical limits on the thrust generation capability of a gravinertial (G/I) field drive. The only limits on the maximum thrust production for a given device are related to the design implementation details of the G/I thruster in question, i.e., how much power it can handle before it burns out and/or flys apart, just like you can build small rockets or large rockets. G/I based thrusters with million pound thrusts or larger are conceivable and probably buildable once the G/I sciences are fully understood. When creating a new science and technology, we take baby steps before we walk, and we have to walk before we run, but IMO we have at least taken the first few steps in this new journey.
It would be interesting if the device actually works but it also appears to be a relativity low thrust device like an ion rocket.Even if it does work you'll still need a conventional rocket or RLV to get a vehicle equipped with it into orbit.
Quote from: JohnFornaro on 04/19/2009 02:52 pmSeems like small thrusts are possible. What you need on a long interstellar flight. Pico-Newtons aren't very much. About the power supply: it's good that it's potentially simple. I have an old tube Mac that probably would be too heavy to levitate itself, but I bet it could climb up a cable to the Moon.Anyhow, the power supply so far is attached to a cable, and the demonstrated force experiments are more like a balance beam, I gather.I like the idea of research for it's own sake, and it's true that investors frown upon an inventor changing his direction without their assent. But I still don't get it. Is this technology at the proof of concep phase?Now to read IAC- 08 – C4.4.7.Woodward's thruster work is at the TRL 5-6. There have been many sorts of "proof of concept." The issue here is that science doesn't actually ever "prove" anything. More what it does is disprove all the alternatives. So point in fact, there is no one single standard of evidence that qualifies as 'scientific", etc. What we have are many people from many backgrounds who each individually think one level of evidence is convincing and another compelling, etc. So the goal is to compile as many sorts of evidence as possible. The rotator evidence is very compelling to me since I understand there are no other proposed effects found in anti-phase to electrostriction that can explain Jim's findings. So far as convincing the larger scientific community is concerned, there's no way to tell how physicists will respond. In general they don't like each other. :-)
Quote from: gospacex on 04/17/2009 08:57 pmQuote from: Star-Drive on 04/14/2009 07:14 pmSo what do you consider “substance” in regards to proving these observed M-E effects are REAL? Supporting experimental data from two or more different sources used to be considered substantiating support, but apparently that is no longer the case in 2009. So what will it take to prove the point to you and the rest of the skeptics in the world that the M-E or its QVF cousin is real and usable?I am not a sceptic, I would be *happy* if someone will prove that 3rd law of Newton can be worked around.It can be the case that the idea, being rather radical, does require verification by more than one team. Extraordinary claims do require extraordinary evidence, in this case, reproduction of the effect by multiple teams.Do not assume that "they" (meaning scientific community) have ill intentions. No amount of complaining that "they" don't take it seriously would help. Ony more independent verifications will.Firstly, please stop asserting that M-E gets 'around' Newtons third law any more than a game of tug-of-war does. The M-E reacts against the rest of the universe, period. While I understand thats a bit big of a concept for some folks, honestly though, it shouldn't be for anybody who has moved beyond the idea that anything outside our solar system is just little light bulbs on a big sphere.
Quote from: Star-Drive on 04/14/2009 07:14 pmSo what do you consider “substance” in regards to proving these observed M-E effects are REAL? Supporting experimental data from two or more different sources used to be considered substantiating support, but apparently that is no longer the case in 2009. So what will it take to prove the point to you and the rest of the skeptics in the world that the M-E or its QVF cousin is real and usable?I am not a sceptic, I would be *happy* if someone will prove that 3rd law of Newton can be worked around.It can be the case that the idea, being rather radical, does require verification by more than one team. Extraordinary claims do require extraordinary evidence, in this case, reproduction of the effect by multiple teams.Do not assume that "they" (meaning scientific community) have ill intentions. No amount of complaining that "they" don't take it seriously would help. Ony more independent verifications will.
So what do you consider “substance” in regards to proving these observed M-E effects are REAL? Supporting experimental data from two or more different sources used to be considered substantiating support, but apparently that is no longer the case in 2009. So what will it take to prove the point to you and the rest of the skeptics in the world that the M-E or its QVF cousin is real and usable?