Cannae/EmDrive

[Aethon]

rfmwguy test 2a.

"Misspoke in video, 500 mg weight simulates downward thrust but lifts laser spot. Thermal lift would be downward movement of laser spot with upwards movement of frustum on balance beam." Edited August 30, 2015 by Aethon

[Jolbucley]

I have largely been a bystander to this “debate†for nearly a year, having long tired of shouting at people who refuse to acknowledge how science works. Yet your impassioned rally against ignorance has reignited my little spark of hope for an informed future, so I’ll contribute my two cents, though I doubt I’m saying anything new.

The idea of pushing on quantum vacuum particles (the hypothesis to which I subscribe) has been around for a long time, as I assume most people who are even vaguely literate in particle physics have toyed with the idea in some form or another, and doesn’t really violate any laws of physics or common sense so far as I can tell; at most it bends the rules a little. I can understand why people would be (pleasantly) surprised to find out that something which fits the notion appears to work; I can’t fathom why anyone would be any more critical of this Cannae Drive than any other potential breakthrough in science, aside from a prescriptive notion of science coupled with extreme ignorance, the latter of which most of us have been guilty at some point or another but the former of which I can’t particularly comprehend. Criticism of this seemingly reactionless drive should be well-informed and limited to the cautious scrutiny with which one ought to approach ANY new technology.

Less than a week after the Cannae Drive hit the media, the discussions to which I was party had stopped being about the drive itself and concerned themselves entirely with how things work versus how they should work. Whether or not the drive works and whatever produced the thrust, it’s good to read something about the issue that actually makes sense for a change, other than the actual reports  you can only read those so many times.

[PB666]

I have largely been a bystander to this “debate†for nearly a year, having long tired of shouting at people who refuse to acknowledge how science works. Yet your impassioned rally against ignorance has reignited my little spark of hope for an informed future, so I’ll contribute my two cents, though I doubt I’m saying anything new.

The idea of pushing on quantum vacuum particles (the hypothesis to which I subscribe) has been around for a long time, as I assume most people who are even vaguely literate in particle physics have toyed with the idea in some form or another, and doesn’t really violate any laws of physics or common sense so far as I can tell; at most it bends the rules a little. I can understand why people would be (pleasantly) surprised to find out that something which fits the notion appears to work; I can’t fathom why anyone would be any more critical of this Cannae Drive than any other potential breakthrough in science, aside from a prescriptive notion of science coupled with extreme ignorance, the latter of which most of us have been guilty at some point or another but the former of which I can’t particularly comprehend. Criticism of this seemingly reactionless drive should be well-informed and limited to the cautious scrutiny with which one ought to approach ANY new technology.

Less than a week after the Cannae Drive hit the media, the discussions to which I was party had stopped being about the drive itself and concerned themselves entirely with how things work versus how they should work. Whether or not the drive works and whatever produced the thrust, it’s good to read something about the issue that actually makes sense for a change, other than the actual reports  you can only read those so many times.

Well the door should not have been shut so quickly as some would have liked. There is alot more work to be done to show its not an artefact, but its nice to see that some have backed a few microns off their original position.

[K^2]

The idea of pushing on quantum vacuum particles (the hypothesis to which I subscribe) has been around for a long time, as I assume most people who are even vaguely literate in particle physics have toyed with the idea in some form or another, and doesn’t really violate any laws of physics or common sense so far as I can tell; at most it bends the rules a little.

That's the problem, you "toyed" with the idea. As a person who actually studied Quantum Field Theory and knows what virtual particles actually are, how to make computations with them, and which rules for ordinary matter they do and do not obey, I can tell you that the idea of using virtual particles as propellant is complete and utter nonsense.

You cannot transfer momentum into quantum vacuum. This is a fundamental violation of conserved currents. I have written pages in this thread about how many things would be completely broken if this was possible, and I have only scratched the surface.

Idea that you can generate thrust from quantum foam is just as absurd as the idea that you can make a wheel generate infinite energy if you arrange magnets on it just right. And for many of the same reasons. We are simply dealing with more sophisticated fields.

The only thing that virtual particles can do is act as very short range intermediaries. They must transfer momentum to something else almost instantly. If no propellant is involved, then the net efficiency of a Q-thruster is that of a photon drive. EMDrive demonstrates efficiency at least an order of magnitude better. That means that a massive, on-shell (not virtual) propellant is involved. And if there is massive propellant, then all you have is a fancy ion thruster. Which is still neat, but it is going to be limited by the same delta-V cap as any other ion thruster. That's all there is to it.

[SuperFastJellyfish]

rfmwguy's Flight Test 2B. Preliminary results seem to show thrust according to a few on the NSF forums. I haven't watched it yet as I'm at work, sadly. Edited September 25, 2015 by SuperFastJellyfish

[Frozen_Heart]

We have a tons of experiments showing thrust, but its the same experiment over and over with no progression or following up.

[PB666]

That's the problem, you "toyed" with the idea. As a person who actually studied Quantum Field Theory and knows what virtual particles actually are, how to make computations with them, and which rules for ordinary matter they do and do not obey, I can tell you that the idea of using virtual particles as propellant is complete and utter nonsense.

You cannot transfer momentum into quantum vacuum. This is a fundamental violation of conserved currents. I have written pages in this thread about how many things would be completely broken if this was possible, and I have only scratched the surface.

Idea that you can generate thrust from quantum foam is just as absurd as the idea that you can make a wheel generate infinite energy if you arrange magnets on it just right. And for many of the same reasons. We are simply dealing with more sophisticated fields.

The only thing that virtual particles can do is act as very short range intermediaries. They must transfer momentum to something else almost instantly. If no propellant is involved, then the net efficiency of a Q-thruster is that of a photon drive. EMDrive demonstrates efficiency at least an order of magnitude better. That means that a massive, on-shell (not virtual) propellant is involved. And if there is massive propellant, then all you have is a fancy ion thruster. Which is still neat, but it is going to be limited by the same delta-V cap as any other ion thruster. That's all there is to it.

This (http://phys.org/news/2015-09-quantum-entanglement-goldilocks-effect.html?quarkcolor=mauve) may have some bearing on how the thruster works.

"Our findings suggest that the universe was 'cooked' at just the right speeds," said Neil Johnson, professor of physics in the University of Miami College of Arts & Sciences and one of the authors of the study. "Our paper provides a simple model that can be realized in a lab on a chip, to explore how such defect structure develops as the speed of cooking changes."

[SuperFastJellyfish]

We have a tons of experiments showing thrust, but its the same experiment over and over with no progression or following up.

What do you think this test is? It's a follow up of his last test with improvements to his balance beam and measurement methods. Here's the walkaround video he did before the latest flight test:

[Scotius]

I did a quick trawl through the following posts. Apparently force is calculated by other users at 90 mg (176 microNewtons). It's not much - but it's already a lot more than photon drive could produce.

[sgt_flyer]

If his results of having net thrust while using a copper meshwire fulcrum can be confirmed in vacuum, it might lead to better understanding on how the fulcrum's shape / structure affect performance of those canae / em-drives. (Even if we still don't know the full physics / quantum physics behind it - making variants of the system can help giving small clues which could help to better understand what's at play there.

Still, with microwaves bouncing inside a metallic structure is bound to generate quite some heat - so his wiremesh approach might help for manqging this heat (at least, within atmospher - (and might allow a better surface for radiative cooling within vacuum)

Edited September 25, 2015 by sgt_flyer

[sal_vager]

Most of the heat is actually in the magnetron and associated hardware rather than the drive itself.

[Scotius]

At least two other users on NASA forum are building their own versions on EmDrives and test rigs. One of them will be a rotary table - in such case thermal effect should have minimal effect on observed behaviour.

[PB666]

Most of the heat is actually in the magnetron and associated hardware rather than the drive itself.

Right, and there is another problem, for the closed end - bell shaped devices there is simply no way for material inside the bell to be ejected through the end plate (other than accelerating particles to the speed of light, not possible in such a short device), and no good reasoning for degassing of copper or copper oxides on the outside face of the plate. This really is getting spooky. All they are doing is creating a resonating electron field inside and apparatus.

In the garage apparatus the RF generator (i.e. microwave) is separate and arbitrarily placed relative to the 'drive' so that its heat and electronics could, with a long enough conductor be rotated 360 degrees, in the XY and 360 degrees in the YZ or any rotation in the XYZ. This is of course a critique and a potential benefit of the crude apparatus, because its modular design means the generator can be directed separately than the copper resonator.

[Albert VDS]

Paul March confirmed over 100µN thrust for 80W power with less than 1µN of EM interaction + thermal characterization on new EmDrive test

[prophet_01]

So they ruled out another possible error? That's good news I guess.

[PB666]

So they ruled out another possible error? That's good news I guess.[/quote']

Unfortunately that website sucks in the rendering, at least with my ipad. Read the letter carefully, they appear to deal with two sources, one having to do with the magnetic field/lorentz interaction, and the other havingdeal with heat interactions.

They have 100 uN of thrust 10 could be explained by EM, 2 by magnetic/lorenze interaction, 1 by heat interaction......leaving 87 uN of thrust unaccounted fo by known physics.

[Streetwind]

So they ruled out another possible error? That's good news I guess.

Yep, checking them off one by one. Paul March's post also mentions that they're already on track to eliminate another one in the next iteration of the test rig.

I'm also quite intrigued by his eagerness to get a test article launched. I didn't think they'd be quite that far yet - usually, test flights in space are done at a fairly advanced stage. But Paul seems convinced that they could stuff everything needed into a 3U cubesat and just toss it up there. He's even been asking people to comment on typical launch prices... while also disclaiming at the same time that there is absolutely no budget for any such thing, not even the cubesat itself. So don't expect anything like that to actually happen. I'm just pointing this out because I find it impressive enough all in itself to know that an involved scientist is saying "the only thing keeping us from throwing this up into orbit right now is money".

[Frozen_Heart]

I thought NASA was meant to be putting out a paper on this around the end of summer? Did they stop work on it?

[Scotius]

According to a recent post from Paul March, that paper will be out in the first half of the 2016. Let's hope this delay was caused by new findings, or increase in financing allowing Eagleworks to get more tests done

[Mazon Del]

Hooray! More data! It's been so long...Good to see though that Paul March has worked out something of a deal with his...censors?...to be able to tells us something at least.

[PB666]

Hooray! More data! It's been so long...Good to see though that Paul March has worked out something of a deal with his...censors?...to be able to tells us something at least.

Not censorship, peer review, they probably asked for major revisions (i.e. you have to go back to the bench and do more work). The most critical referee that does not eventually reject your paper, in the long run, is your best friend. The last place you want to see a mjor error revealed is in the headline of some newspaper after yor work is published.

[Mazon Del]

Indeed it is the proper way of doing things. I'm still just bitter because every day I got to come into work and in the inevitable 3 hours of nothingness that happen, I got to sit and read up on/participate in what was going on there rather directly. Positing questions, discussing possibilities, etc. And then suddenly the iron curtain descends and I'm cut off. T_T

[Streetwind]

Not censorship, peer review

He doesn't mean the paper, but rather the stipulation that scientists involved in the project may no longer share information about it outside of approved press releases.

Originally they started out with a perfectly open information policy, and scientists like Paul March provided what was almost a daily play-by-play reporting of what was going on in the lab. And then the press picked up on it and told the public that NASA was building a spaceship with a miracle warp drive. Considering that (contrary to what the press says) this isn't even an officially funded project, this caused so much confusion and so many problems for NASA, for Eagleworks and for the invovled people that at some point everyone was called into a room and issued a gag order. No more talking about EMdrive testing, period.

That Paul March is even saying anything at all right now can probably be attributed to the fact that the press stopped paying attention when they could no longer get any scoops on their imaginary warp drive. I get the impression from his posts that he wants to say more, but needs to stick to what's been cleared for release.

[passinglurker]

moral of the story "The press ruins everything"

[PB666]

He doesn't mean the paper, but rather the stipulation that scientists involved in the project may no longer share information about it outside of approved press releases.

Originally they started out with a perfectly open information policy, and scientists like Paul March provided what was almost a daily play-by-play reporting of what was going on in the lab. And then the press picked up on it and told the public that NASA was building a spaceship with a miracle warp drive. Considering that (contrary to what the press says) this isn't even an officially funded project, this caused so much confusion and so many problems for NASA, for Eagleworks and for the invovled people that at some point everyone was called into a room and issued a gag order. No more talking about EMdrive testing, period.

That Paul March is even saying anything at all right now can probably be attributed to the fact that the press stopped paying attention when they could no longer get any scoops on their imaginary warp drive. I get the impression from his posts that he wants to say more, but needs to stick to what's been cleared for release.

I know of editors that won't take manuscript if the information has been published anywhere else, peer reviewwed or not. The real experimental stuff needs to be kept hush-hush until publication.