EmDrive

[crazyewok]

I agree its not hard to look smarter than US government!

To be fair I think the reason NASA is in the state it is now is because of the interfering the fools in congress. When decision making is made by people who think the universe is 6000 years old and spending 60 billion on a fighter program that produces fighters that randomly catch fire is ok, then scientific departments will suffer.

Edited August 5, 2014 by crazyewok

[Jackissimus]

That doesn't make any sense whatsoever. That's a pretty obvious side-effect to account for, so why would anyone be testing it in air? It wasn't even designed for that.

From wikipedia: "Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a sealed stainless steel vacuum chamber, but at ambient atmospheric pressure, because the RF power amplifier used an electrolytic capacitor not capable of operating in hard vacuum."

[Aghanim]

Well, this is what really happens.

NASA found an anomalous thrust in their experiment, just like CERN found an FTL neutrino. They posted the result in a paper, saying that we don't know where this thrust come from, and they are trying to replicate this in other places. Then, as CERN found out, those 'FTL' neutrino is because a fiber optic cable is installed incorrectly, and so the speed of light measurement is wrong. But because this 'discovery' is amazing, the journalists are jumping to it, making up hype.

Of course, the original paper is paywalled, so the best thing that we can do is hope someone is leaking the real paper, not this

Just like it doesn't make any sense to write huge headers in news media about "impossible drive working" while in their experiment non-functional metal box produced exactly the same results as the "drive" they were testing.

Hype in media and on a forums over this whole thing went waaaay over the board.

This is why we need the paywalled paper to resolve this thing once and forever. How do they even know what to remove so the drive will not work, assuming that they doesn't know what makes the unknown force? Looking back, I do agree with you. The journalists are sensationalizing something that they doesn't have enough information on, making mistakes all the way

EDIT: Link to the real research paper is here: http://arc.aiaa.org/doi/book/10.2514/MJPC14

The bad news? It costs $240 (Nibb31 I know you can buy it for the sake of the entire world, I will give you money to do it)

And here is an example. Lets say you are eating a strawberry cake. And you got sick. Then you eat a strawberry waffle. And then you got sick. So you think that the strawberry is the thing that makes you sick, so you make a waffle without strawberry. And then you still got sick. You make the strawberryless waffle witht the expectation of it doesn't make you sick, so you are making it the control. But the control and the tested strawberry waffle makes you sick.

Edited August 5, 2014 by Aghanim

[Nuke]

From wikipedia: "Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level, within a sealed stainless steel vacuum chamber, but at ambient atmospheric pressure, because the RF power amplifier used an electrolytic capacitor not capable of operating in hard vacuum."

the solution to that problem is to use a solid state capacitor instead. or you absolutely need to use an electrolytic you can seal it in a can with 1 atmo of argon or some other inert gas. this is a solvable problem and the fact that they didnt do this sounds rather fishy. they probibly already sell milspec caps for this kind of application. in which case spend a few bucks on parts.

[Mazon Del]

From my understanding they built the rig kinda out of stuff they just had sitting on shelves. It was cheaper to use the electrolytic capacitor because that is why they had. I'm sure they will be investigating this more thoroughly, trying to figure out both how to make the engine, and how to make it fail.

[The Jedi Master]

Does anyone actually know how this thing works? Or are the folks at NASA just saying "MAGIC"?

[ZetaX]

They obviously want(ed) to show it doesn't, and very likely it won't in more rigid tests.

[ThesaurusRex]

Does anyone actually know how this thing works? Or are the folks at NASA just saying "MAGIC"?

In quantum mechanics, small particles are theorized to pop in and out of existence. The drive, hypothetically, is propelling these particles before they pop out of existence, imparting momentum into the hypothetical craft.

[crazyewok]

In quantum mechanics, small particles are theorized to pop in and out of existence. The drive, hypothetically, is propelling these particles before they pop out of existence, imparting momentum into the hypothetical craft.

So basically we don't know so magic particles do it? Rrrrrrrrriiiiiiiiiiggggggghhhhhhhtttttt

May as well say its powered by magic fairy farts.

[Kerbart]

So basically we don't know so magic particles do it? Rrrrrrrrriiiiiiiiiiggggggghhhhhhhtttttt

May as well say its powered by magic fairy farts.

If it works NASA will give a ***** if the thrust comes from quantum bibaglion frupturts or from Unicorn farts; it would allow them to launch probes to nearby stars.

Mind you, I highly, highly doubt it works.

[Sky_walker]

If it works NASA will give a ***** if the thrust comes from quantum bibaglion frupturts or from Unicorn farts; it would allow them to launch probes to nearby stars.

No it wouldn't. It's not enough thrust even for a station keeping. And these things don't scale well - just to give you a rough idea: Small solar sail on IKAROS satellite produces ~22 times as much thrust as this thing, yet: it only weights a tiny fraction of what that metal box does.

BTW: grats for 600 posts.

[Rickenbacker]

Sounds kind of impractical, even if it does work. And that's yet to be proven, if I read the short report on NASA's page correctly, they tested it in normal atmospheric pressure, where the effect might have come from pushing air molecules, or something similar.

[Z-Man]

So basically we don't know so magic particles do it? Rrrrrrrrriiiiiiiiiiggggggghhhhhhhtttttt

Well, to their credit, those particles do exist and their effects have been experimentally demonstrated... It's just

1. They are just a pretty picture of what the nontrivial vaccum of QED looks like; it is useful for some problems, but not all.

2. They pop into existence with zero combined momentum and to vanish again, they need zero combined momentum. You can't just let them show up, dump momentum into them, then bugger off. You either need to dump enough energy into them to turn them into real particles (nothing gained then) or they use their power of quantum precognition (complaining that this is not a thing? See point 1.) and not turn up in the first place or refuse to interact with your device.

And none of the original explanations for the EMDrive and Cannae Drive even use virtual particles. They're purely classical (relativistic) electrodynamics. It's at this point massively unclear to me what kinds of devices were tested, though.

[Sky_walker]

[YNM]

http://scienceblogs.com/principles/2014/08/04/impossible-thruster-probably-impossible/

Some links pointed by the guys at Explain XKCD.

Safe to say, also the same to those pendulum thrust thing, there're simply too many fluctuations. The only reason why you can't see individual asteroids (because α PsA have an observable disk) orbiting other stars by transit method (yet, least) is due to the noise - until it get sorted out by other observations (like visual method, or comets coming back to a PN).

[Mazon Del]

No it wouldn't. It's not enough thrust even for a station keeping. And these things don't scale well - just to give you a rough idea: Small solar sail on IKAROS satellite produces ~22 times as much thrust as this thing, yet: it only weights a tiny fraction of what that metal box does.

It certainly is enough thrust for station keeping of satellites, right now that is the primary application people are interested in. As far as scaling, I have heard mixed reports on scaling, some saying its a problem (without any citation) and others stating it isn't a problem (also without citation). Regardless, if the system works to any degree comparable to a solar sail it will be utilized over them. Solar sails have a few problems that tend to get overshadowed by the idea of just making them bigger. Primarily the fact that deep within a solar system (where we are) there is enough stuff floating around that they will degrade noticably over time. If you are lucky your degradation will tend towards a general degradation of capability, if you are unlucky then you are going to need to 'constantly' (every couple weeks?) need to recalibrate how the sail operates. The bigger the sail, the more degradation you can sustain and still be mission capable. And they are heavily dependent upon a local source of energy (sun or laser platform). Once you start getting to the far outter sections of the solar system or places with no infrastructure, the use of a solar sail quickly becomes problematic. If we identify a specificed size/power input for the thrusters that makes them even partially comparable to a solar sail in terms of thrust abilities, it would be FAR better to just have a large bank of these. You can keep them inside your protective hull, thus reducing degradation over time. They work as long as you have electricity, etc.

[RuBisCO]

A crude summary of the stages of scientific turthiness:

Someone makes a claim = "BS"

Someone makes a claim and reports it in a peer review journal = "Intresting, but probably BS"

Someone test that claim and comes up with the same or similiar results = "Fascinating, perhaps this is not BS"

Someone repeats testing of claim with variation and gets similiar results with a model showing what variation does = "Well this appears to be the scientific consensus"

Someone repeats the testing of the testing of testing of the claim and gets the same results that fit within the model = "Established Scientific theory"

Someone with limited education can be instructed to test and can validate the claim that has been tested, re-tested and modeled = "Fact"

EMdrive appears to be at stage 2 or even 3. Of course to make it to stage 4 requires more 3rd parties to test and validate and publish their validations in peer review journals, if no one manages to validate or many manage to disprove it, then it falls back to BS. I like the dramatic though: because of the extraordinariness needed to accept this, for it appear to violate conservation of momentum and energy, something that has been stage 6 for centuries now. I think they are going to need a spacecraft run laps around the solar system before most everyone accept this as fact. A couple more labortory experiements are simply not going to do it to convince the scientific community or most of humanity.

How it manages to work despite appearing to violate conservation of momentum, explain that to me after you have shown me it fly out of earth orbit and back, else why should I listen to BS?

Edited August 6, 2014 by RuBisCO

[Z-Man]

http://scienceblogs.com/principles/2014/08/04/impossible-thruster-probably-impossible/

Splendid read. Also two links in (via Baez, also always worthwile), the full article (may no longer work by the time you click it):

http://rghost.net/57230791

So yes, the information in Wikipedia is essentially correct. They tested the Cannae Drive, a dummy modified Cannae Drive without the slots, and a device very similar to the EMDrive (though never referenced as such), key difference being that this one also was half filled with a dielectricum. And test loads to verify they got no thrust/torque from cables and stuff. Power levels were 17 Watt, tops, a rare case of XKCD getting numbers wrong. That the dummy device produced the same results as the real device is not terribly surprising: The slots are way too small to have a significant effect on waves of that frequency.

One more little observation: They do not say which way the thrust went when they mounted the devices the other way round. I'd assume it also changed direction, but I also would assume you put things into a vacuum chamber to test them in a vacuum, so there.

And on the pictures, you see that the devices are almost touching the vacuum chamber walls. If it's not thermal effects from the air inside the chamber, definitely near field effects are next on the suspect list of perfectly normal explanations.

[Albert VDS]

Did NASA Validate an “Impossible†Space Drive? In a Word, No.

http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.U-KYHVJNfFo

[vger]

So basically we don't know so magic particles do it? Rrrrrrrrriiiiiiiiiiggggggghhhhhhhtttttt

May as well say its powered by magic fairy farts.

Ah, stereotypical skeptic rage, with the most predictable of terminology.

As if other aspects of particle physics as any less 'crazy' in how they work.

Edited August 6, 2014 by vger

[Northstar1989]

If something sounds too good to be true...

You must remember that airplanes would have sounded too good to be true to cavemen.

Clarke's Third Law:

"Any sufficiently advanced technology is indistinguishable from magic."

http://en.wikipedia.org/wiki/Clarke%27s_three_laws

Regards,

Northstar

Edited August 7, 2014 by Northstar1989

[Northstar1989]

Did NASA Validate an “Impossible†Space Drive? In a Word, No.

http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.U-KYHVJNfFo

The article is little more than stereotypical skeptic rage. It doesn't actually raise a single point about the data or science itself.

All it does is take the author's arrogance in assuming a single friend of his at Caltech know everything (I've talked with actual elderly physics PROFESSORS, with a lot more experience in physics than his friend, who described the Quantum Vacuum in a way that made something like a Q-drive/EmDrive seem plausible years ago...) and combine that arrogance with a hefty dose of "if it's too good" pseudo-logic.

I'm not saying the "Cannae Drive" that's been circulating the news will turn out to be valid/reproducible. In fact, it's probably less likely than not. But articles like that don't do anybody any good, and just muddy the water further.

Good thing it was little more than an editorial.

Regards,

Northstar

Edited August 7, 2014 by Northstar1989

[Northstar1989]

http://scienceblogs.com/principles/2014/08/04/impossible-thruster-probably-impossible/

Some links pointed by the guys at Explain XKCD.

Safe to say, also the same to those pendulum thrust thing, there're simply too many fluctuations. The only reason why you can't see individual asteroids (because α PsA have an observable disk) orbiting other stars by transit method (yet, least) is due to the noise - until it get sorted out by other observations (like visual method, or comets coming back to a PN).

Pendulum and torsion thrust-measuring devices are commonly used to measure ion engine thrust. There's nothing unconventional or unproven about the measuring equipment- there's a reason NASA had the equipment in the first place (it works).

Aide from criticizing the motivation of the scientists themselves on rather fuzzy logic, the only REAL criticism is that the "null" and "experimental" devices both produced thrust- a criticism that popped up once on the internet, and seems to have been mirrored many times since.

Unfortunately, what the people making that criticism did NOT understand, is that the "modification" (slots/roughening on the end of the device) was controversial in the first place. While Fetta (the American scientist to build HIS OWN version of the EmDrive and re-name it the "Cannae Drive") included these slots, and thought they were necessary, other previous versions of the drive included no such slots, and appeared to work perfectly fine. Thus, the "null" version of the drive (the use of the term null comes mainly from the critics, not the article itself) was not actually a null-version. It was an alternative, simpler version of the drive that was proven to work just as well.

The ACTUAL null version of the drive was the "RF load" the abstract of the data talks about. THIS TEST was an actual null version of the drive designed to replicate the same electricity consumption, RF frequency emissions, etc., and produced no thrust- thus validating the test of thrust production.

Being an actual scientist in real-life, with experience in an equally controversial area of research (Stem Cell Research- you could actually find my name in the scientific literature if you knew my real last name...), I can tell you from stories I've heard from a number of professors that critics have an extreme tendency to twist the words in your abstract to mean things they were never meant to mean. One little ambiguity, and it will be taken as proof that nothing you say is valid, if the reader doesn't want to believe your data/results. This is a VERY good reason to take the criticism with a grain of salt, just as the critics are taking the abstract with a whole boat-load of it...

Regards,

Northstar

[Scotius]

One good thing should come from this debate - more science teams should be willing to test Em\Cannae Drives. With bigger sample we should come closer to finding if it works or not. And how it works if more tests give positive results.

[KerbMav]

Aide from criticizing the motivation of the scientists themselves on rather fuzzy logic, the only REAL criticism is that the "null" and "experimental" devices both produced thrust- a criticism that popped up once on the internet, and seems to have been mirrored many times since.

Unfortunately, what the people making that criticism did NOT understand, is that the "modification" (slots/roughening on the end of the device) was controversial in the first place. While Fetta (the American scientist to build HIS OWN version of the EmDrive and re-name it the "Cannae Drive") included these slots, and thought they were necessary, other previous versions of the drive included no such slots, and appeared to work perfectly fine. Thus, the "null" version of the drive (the use of the term null comes mainly from the critics, not the article itself) was not actually a null-version. It was an alternative, simpler version of the drive that was proven to work just as well.

Ah, I was only today reading an article that mentioned this.

So basically they are wondering why the red car drives as well as the blue one?

that critics have an extreme tendency to twist the words in your abstract to mean things they were never meant to mean. One little ambiguity, and it will be taken as proof that nothing you say is valid, if the reader doesn't want to believe your data/results.

Coming from the right scientific field you might be able to answer this question: Do critics in the scientific world and forum/comments posters share more or less than 90% or their genetic code?