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So it's not huge output compared to propellant based drives (we're talking several orders of magnitude less ... which is somewhat mitigated by not needing to haul tons of fuel), but the results ranked it a couple of orders of magnitude more powerful than light sails.
If it is actually working. It violates Newton's third law (equal and opposite reactions). I'm pretty hopeful, though. Things get weird when you delve into quantum physics...
Next testing should be space based, so if it succeeds there, that should eliminate a good number of the sources of possible errors.
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Thank you!
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... waaaaaaaat?
Hm. Dotting for future.
Lol the media is going insane over this. "70 days to Mars!" What!
Despite the jovial nature of my post above, I'm not actually dismissing the idea out-of-hand... but it's definitely worth being skeptical of, if only because it requires what is currently deemed as (at best) pseudo-science to function in the way it seems to be functioning.
The concept of literally gaining energy ex nihilo* is... well...
Let's just say even the Plenipotent Dominion would be interested in such.
(I don't know enough about the Archailects to know if it would be significant to them, or not.)
*
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Simple solution: The third law of thermodynamics as science understands it is wrong. It's not the only one, but it's the most glaring example.
The third law? Thermodynamics? ("The entropy of a perfect crystal at absolute zero is exactly equal to zero.") What the frack does entropy have to do with it?
The laws that this breaks are Newton's third law and, perhaps more importantly, the law of conservation of momentum. The second is more important because conservation of momentum is tied to one of the Noetherian symmetries. We can prove mathematically that if the laws of physics are consistent across space, then momentum is conserved -- which means that if the Em-drive works as advertised, then the laws of physics are not the same everywhere in the universe. (And since space and time are hard to separate, the law of conservation of energy is likely to vanish, too.)
... and boy will that put the cat amongst the pigeons when the astrophysicists start working the implications of that one out.
I mean, yeah, it's possible that any given scientific theory as we understand it is wrong, but conservation laws are like a knitted sweater; when you start pulling seriously on a snag, the whole thing unravels.
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Two possible solutions: the third law of thermodynamics motion is not 100% right buts only crude approximation of how the actual reality works, and in certain conditions there becomes discrepancy between its math and actual results. We might be just used to live in conditions where that approximation is enough for our purposes and close to predict macroscale effects. (Gee, it's not like that happened with any of Newton's laws before)...
Second solution: the third law of thermodynamics motion was not violated, we just failed to detect the equal reaction.
EDIT: Third law this, third law that. Probably single article said third law, then another added "third law of thermodynamics" and so everyone repeated thinking of the right law ("each action causes equal reaction") using the wrong name.
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Simple solution: The third law of thermodynamics as science understands it is wrong. It's not the only one, but it's the most glaring example.
Speaking to the actual law you meant... It's also possible energy is coming from somewhere we're not aware of. At this point NASA has torn that thing apart and put it back together again a million times, so it's not complete crud. They've measure the output hundreds of times. They where correct to question it, and still are, but it's got enough evidence behind it that it's safe to say, "It seems to be outputting some energy but we're not sure how it's doing it." As I understand it, the article NASA released did suggest some possibilities using current theories (though not hugely popular ones). The more this thing works the more we'll dig to update our understanding of reality.
I'm glad NASA has the program to test out these sorts of inventions. A good deal aren't worth the investment or are straight up cons, but every once in awhile someone comes up with something good.
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Two possible solutions: the third law ofthermodynamicsmotion is not 100% right buts only crude approximation of how the actual reality works, and in certain conditions there becomes discrepancy between its math and actual results. We might be just used to live in conditions where that approximation is enough for our purposes and close to predict macroscale effects. (Gee, it's not like that happened with any of Newton's laws before)...
This wouldn't actually address the issue, since non-conservation of momentum, even if it only happens a little bit, still proves that the laws of physics are only local ordinances. It's not enough to say that momentum conservation is violated "under certain conditions," because those conditions themselves are place-dependent. (Unlike special relativity; that is a [presumably] universal description of what happens when something moves really fast, but it happens to any object, no matter where it's located.)
So, basically, if the Em-drive works as advertised, the laws of physics are merely local ordinances. Who knows what the fine structure constant is near a distant star?
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It's still far, far more likely that we're seeing experimental error here.
NASA has said as much, citing (IIRC) 9 possible sources for errors in their paper. However, space based testing, if successful should eliminate most if not all of those possibilities.
Really hoping the space based tests prove the EM Drive to be a valid propulsion system.
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Forget using it to travel anywhere. I want to slap two of these on opposite sides of a flywheel in space and let it slowly spin up until a few decades later it explodes. (It'll need some solar panels for power.)
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Forget using it to travel anywhere. I want to slap two of these on opposite sides of a flywheel in space and let it slowly spin up until a few decades later it explodes. (It'll need some solar panels for power.)
Actually, if the results are valid, it produces significantly more thrust than light sails (talking ~1.2 millinewtons/kW vs ~4.5-5 micronewtons/kW). Granted it is a far cry from an ion drive (~60 millinewtons/kW), but it does not require the massive amount of fuel an ion drive requires. With in the inner system, it could feasibly utilize solar power as a ready energy source; the further out you go though, the less efficient that becomes, so you would be looking at nuclear more than likely.
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So it's not huge output compared to propellant based drives (we're talking several orders of magnitude less ... which is somewhat mitigated by not needing to haul tons of fuel), but the results ranked it a couple of orders of magnitude more powerful than light sails.
If it is actually working. It violates Newton's third law (equal and opposite reactions). I'm pretty hopeful, though. Things get weird when you delve into quantum physics...
Next testing should be space based, so if it succeeds there, that should eliminate a good number of the sources of possible errors.
1. Remember National Geographic is now a Fox News organ, and it's run by a climate change denier.
2. Newton's laws date from the 18th century. The purpose of Einstein's relativity, Bohr's quantum mechanics, and the work of others is to cover the gaps that Newtonian Physics falls short in.
3. Even the best news organisations are absolutely horrible at reporting science. They frequently tend to overblow what is actually reported.
4. What has not been specified is whether or not the reported results are significantly higher than the range of error in measurement.
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Cone-shaped metallic object with particle impacts, interaction of energy state particles could be creating micro-magnetic resonance waves that would slightly shift nearby particles projected pathways, there by altering refraction of impacts enough that an imbalance occurs where vector force fails to cancel, and the cone shape helps to direct this now excess vector force.
That's not actually an explanation, though. (According to standard theory), momentum is conserved even at the quantum level. If this "micromagnetic resonance wave" is a thing capable of exerting force, it exerts force symmetrically, such that the net change in momentum across the system is zero.
Or, more bluntly, "where vector force fails to cancel" is literally impossible according to standard theory.
The alternative, of course, is that for some reason, momentum is not conserved and it's possible for some sort of interactions, quantum or otherwise, to generate non-zero net force. But in this case, math takes over and we're facing Noether's theorem again.
it seems possible.
Oh, sure, it's possible. It simply violates one of the core beliefs on which all of modern physics is based, including quantum mechanics itself. So one is not going to be able to get out of it simply by postulating spooky quantum effects, since the spooky quantum effects themselves say that it's not possible for this drive to work as described.
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4. What has not been specified is whether or not the reported results are significantly higher than the range of error in measurement.
So, do you think that the NASA engineers are idiots, or that the journal reviewers are? Because this is the sort of mistake that would be caught by a smart high school student.
1.2 +/- 0.1 mN/kW, so about twelve times greater than the error range.
Similarly, if for some reason National Geographic or the scientific press more generally bothers you, I've attached a link to the paper itself, as published in Journal of Propulsion and Power. As far as I can tell, NG got this one right.
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The EM drive certainly seems a million times more viable than the 1989 cold fusion claims. :)
4. What has not been specified is whether or not the reported results are significantly higher than the range of error in measurement.So, do you think that the NASA engineers are idiots, or that the journal reviewers are? Because this is the sort of mistake that would be caught by a smart high school student.
1.2 +/- 0.1 mN/kW, so about six times greater than the error range.
Similarly, if for some reason National Geographic or the scientific press more generally bothers you, I've attached a link to the paper itself, as published in Journal of Propulsion and Power. As far as I can tell, NG got this one right.
What I think is that the state of science reporting in this country generally runs a range from abysmal to outright fraud.
The fact that NASA itself isn't saying anything on it's own sites, should give one pause.
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The fact that NASA itself isn't saying anything on it's own sites, should give one pause.
Not really. Have you actually looked at their website? They don't include any papers; it's all PR fluff about "Spacecraft 'Nuclear Batteries' Could Get a Boost from New Materials" and the material is pretty out of date by the time it gets posted (today's headline technology article is dated October 13, 2016, more than a month before the paper we're discussing was even released as a prepublication). NASA's "own sites" are not channels for technical publication -- which makes sense, because they use the journals like other real scientists. It's actually considered pretty poor form to publish stuff through your own web page.
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What I think is that the state of science reporting in this country generally runs a range from abysmal to outright fraud.
Well (shrug) you're wrong, at least in this instance. As you could confirm for yourself with thirty seconds of research.
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It's still far, far more likely that we're seeing experimental error here.Simple solution: The third law of thermodynamics as science understands it is wrong. It's not the only one, but it's the most glaring example.The third law? ("The entropy of a perfect crystal at absolute zero is exactly equal to zero.") What the frack does entropy have to do with it?
The laws that this breaks are Newton's third law and, perhaps more importantly, the law of conservation of momentum. The second is more important because conservation of momentum is tied to one of the Noetherian symmetries. We can prove mathematically that if the laws of physics are consistent across space, then momentum is conserved -- which means that if the Em-drive works as advertised, then the laws of physics are not the same everywhere in the universe. (And since space and time are hard to separate, the law of conservation of energy is likely to vanish, too.)
... and boy will that put the cat amongst the pigeons when the astrophysicists start working the implications of that one out.
I mean, yeah, it's possible that any given scientific theory as we understand it is wrong, but conservation laws are like a knitted sweater; when you start pulling seriously on a snag, the whole thing unravels.
For what it's worth, I agree, but the guys in the lab (and as far as I can tell, yes, they were all "guys") did a pretty good job of listing potential sources of error [section 8] and discussing why they don't think that any of them could have produced the effects shown. For example, number 1 is "air currents affecting testing apparatus," but they tested the thing in a vacuum (or near-vacuum, anyway) and got the same results. Number 6 is "electrostatic interaction," but everything was confirmed to be well-grounded.
If you think there's any source of error that they missed, I'm sure they'd be happy for your feedback. Otherwise saying "experimental error" isn't particularly helpful.
Simple solution: The third law of thermodynamics as science understands it is wrong. It's not the only one, but it's the most glaring example.The third law? Thermodynamics? ("The entropy of a perfect crystal at absolute zero is exactly equal to zero.") What the frack does entropy have to do with it?
The laws that this breaks are Newton's third law and, perhaps more importantly, the law of conservation of momentum. The second is more important because conservation of momentum is tied to one of the Noetherian symmetries. We can prove mathematically that if the laws of physics are consistent across space, then momentum is conserved -- which means that if the Em-drive works as advertised, then the laws of physics are not the same everywhere in the universe. (And since space and time are hard to separate, the law of conservation of energy is likely to vanish, too.)
... and boy will that put the cat amongst the pigeons when the astrophysicists start working the implications of that one out.
I mean, yeah, it's possible that any given scientific theory as we understand it is wrong, but conservation laws are like a knitted sweater; when you start pulling seriously on a snag, the whole thing unravels.
Newton's laws are not inviolate, especially on the quantum level. Violations ARE allowed as long as the sum and time of those violations do not exceed the Planck constant. No matter what the EMDrive is (or is not doing) nothing has changed the way those laws operate on the macro level.
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Newton's laws are not inviolate, especially on the quantum level.
But conservation of momentum and of mass/energy are. (At least according to our standard theories at the moment, which are backed up by rigorous mathematical proof that if they aren't, then the "laws of physics" don't actually exist since they vary with place and time.)
No matter what the EMDrive is (or is not doing) nothing has changed the way those laws operate on the macro level.
Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.
Newton's laws are not inviolate, especially on the quantum level.But conservation of momentum and of mass/energy are. (At least according to our standard theories at the moment, which are backed up by rigorous mathematical proof that if they aren't, then the "laws of physics" don't actually exist since they vary with place and time.)
No matter what the EMDrive is (or is not doing) nothing has changed the way those laws operate on the macro level.
Even conservation of matter and energy CAN be violated on the quantum level. Newton's Laws simply are not ironclad when you are operating in the realms of quantum mechanics or relativity... which is why those mechanics had to be invented. The easiest macro observation of this is the timing of the orbit of Mercury.
Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.
That in itself is not an issue, the accleration of the expansion of space is an example of a force without a counterforce. What you have to keep in mind is that Newtonian mechanics ARE NOT ABSOLUTE. They get kicked to the curb at the quantum or relativistic spheres. And there may yet be other spheres of operation besides quantum and relativity, it would be foolish to assume that we've discovered them all.
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Even conservation of matter and energy CAN be violated on the quantum level.
Nope. That's one of the key insights of Noether's theorem.
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Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.Okay, for those of us whose science education was American public school and we didn't even do well at that (yes, I am counting the voices in my head), could you explain this in more detail?
Not a foundation for an argument. I'm actually kinda lost at this point. Thought I had the thread earlier.
As far as we know, there's no way to accelerate without having something to push against or having something push against you (because those are the same thing). Rockets work by throwing light stuff "really, really fast" to move heavy stuff "fast". But because you have to throw stuff away, you run out of stuff. (Bonus problem, you had to move that stuff part way as well.) This, if correct, lets us move something faster by bouncing stuff around inside it. It's not free- you still have to provide power- but you don't have to throw anything away or count on stuff hitting you from outside.
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Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.Okay, for those of us whose science education was American public school and we didn't even do well at that (yes, I am counting the voices in my head), could you explain this in more detail?
Drahliana Moonrunner is pointing out, using rather loose terms, that on a small enough (Planck) scale, momentum itself is uncertain and that (depending upon how you interpret QM), there can be extremely small, extremely short-lived variations in the momentum of a system (or of parts of a system). However, by the same math, these variations disappear when you measure a change over a larger system, and the relationship between system size and variations in measurements is very well understood.
As this web site puts it (well): "Heisenberg's uncertainty principle has nothing to do with it, as it is just a statement about standard deviations, not expectation values, and hence has no influence on the quantum version of conservation."
If you read the paper (which I linked to upthread), the researchers used a piece of fairly ordinary lab equipment, a torsion balance, to measure the thrust generated by the EM-drive. Any measured thrust, especially a thrust in the range of milliNewtons, would be produced by the combined effects of many, many quantum interactions (in this case, "many, many" is a number large enough that I don't even know the name, something like 10^18).
So when we're dealing with a system this large, the variance in individual photon behavior disappear (well, more formally, they have an effect roughly equivalent to 1/10^18th of the overall system behavior). Essentially, it's the argument that if you roll a die twice and get two sixes, that's interesting. If you roll a die two hundred times and average 5.87, that's not interesting, that's a finding and probably a weighted die.. If you roll a die 10^18 times and average anything measurably different than 3.500, it's not a fair die.
So if the EM-drive generates any measurable thrust due to quantum interactions, then the expected net momentum of the quantum interactions in the drive must be different than zero. But standard quantum theory demands that the interactions be zero exactly.
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As far as we know, there's no way to accelerate without having something to push against or having something push against you (because those are the same thing). Rockets work by throwing light stuff "really, really fast" to move heavy stuff "fast". But because you have to throw stuff away, you run out of stuff. (Bonus problem, you had to move that stuff part way as well.) This, if correct, lets us move something faster by bouncing stuff around inside it. It's not free- you still have to provide power- but you don't have to throw anything away or count on stuff hitting you from outside.Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.Okay, for those of us whose science education was American public school and we didn't even do well at that (yes, I am counting the voices in my head), could you explain this in more detail?
Not a foundation for an argument. I'm actually kinda lost at this point. Thought I had the thread earlier.
The Acubierre effect does not rely on impulse either. It does have it's operational issues, mainly that you can't navigate, you can't steer, and that once it's invoked, there isn't a way to turn it off.
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{whispers into cellphone:} Yeah, MP, your plan was a genius. This is really f!cking with their minds. Hm? Oh, right now I'm planting evidence that the drive screws with reality... replacing their lab's coffee creamer with whiteout, replacing all the lifesavers in the vending machine with pre-licked green ones, hiding all the red staplers... yeah, it's going great.
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As far as we know, there's no way to accelerate without having something to push against or having something push against you (because those are the same thing). Rockets work by throwing light stuff "really, really fast" to move heavy stuff "fast". But because you have to throw stuff away, you run out of stuff. (Bonus problem, you had to move that stuff part way as well.) This, if correct, lets us move something faster by bouncing stuff around inside it. It's not free- you still have to provide power- but you don't have to throw anything away or count on stuff hitting you from outside.Er, no. At the macro level, it apparently produces a force without a counterforce, which again violates the various conservation laws -- it produces a measurable force on the (macroscopic) equipment.Okay, for those of us whose science education was American public school and we didn't even do well at that (yes, I am counting the voices in my head), could you explain this in more detail?
Not a foundation for an argument. I'm actually kinda lost at this point. Thought I had the thread earlier.
One way to think about it -- can you move your car by sitting in the driver's seat and pushing on the steering wheel? More accurately, why can't you?
The answer, according to conventional physics, is that when you push on the steering wheel, the wheel pushes back on you in exactly the same manner, so the net effect is nothing. You can push your car from outside the car, because you're pushing against both the ground and the car simultaneously, so the ground moves backwards slightly and the car moves forwards slightly. Similarly, when you shoot a firearm, the energy of the propellant pushes the bullet forward and the firearm itself backwards, which is why the gun "kicks."
The same holds true at a quantum level as well. When an electron emits a photon, the photon carries momentum away, so the electron changes direction slightly; the photon goes off to the left, and the electron heads off to the right.
In the EM-drive, there are lots of photons hitting the walls of the chamber. The photons that hit the front wall of the chamber should push the chamber forward slightly (and the photons bounce backwards, like a basketball hitting the backboard). Similarly, the photons that hit the back wall of the chamber will push the chamber backwards, while the photons bounce forward. Standard QM predicts that, like the man pushing on the steering wheel, the net effect should be zero exactly. But since the EM-drive seems to generate thrust, the forward pushing effect, which is (may be?) the combined effect of zillions of microinteractions, is greater than the backwards pushing effect. Which just shouldn't happen.
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The Acubierre effect does not rely on impulse either. It does have it's operational issues, mainly that you can't navigate, you can't steer, and that once it's invoked, there isn't a way to turn it off.
It also involves "stuff" that's not known to exist and is not compatible with quantum mechanics (it only uses general/special relativity). I'm not sure I'd rely on Alcubierre's [sic] work in a discussion of quantum effects.
I'll take it seriously the day they actually stick it on a probe and try it out...
And then if it works, I'll start demanding a Pluto orbiter.
I'd love to see that world close up again before I die.
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~looks at my math and scratches my head~ ! + 1 = 3 ? What am I missing? Did I forget to carry the imaginary cosine?
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Oh wonderful, here is was finally grasping the fact the light is and is not matter and does and does not have mass. Stupid science making us not smarts confused and such.
I'd not worry about it. Richard Feynman is famously supposed to have said "If you think you understand quantum mechanics, you don't understand quantum mechanics." Niels Bohr is documented as saying "hvis man kan sætte sig ind i kvantemekanik uden at blive svimmel, har man ikke forstået noget af det," which roughly translates as "if you understand quantum mechanics without getting dizzy, you don't understand anything about it."
One of the major issues of the public understanding of science, especially of physics, is that people latch onto simplifications and judge new findings against their simplified understanding instead of against what the actual theories and models are, and quite often there are huge differences.
Drahliana Moonrunner is doing something like that. She keeps insisting that violation of conservation of momentum is possible because "Newtonian mechanics ARE NOT ABSOLUTE," not realizing that the case for conservation of momentum in quantum physics is, if anything, even stronger. She's misunderstanding the Heisenberg uncertainty principle to include uncertainty in the mean instead of the variance. Actually, these are quite sophisticated errors and bespeak a high degree of scientific literacy on her part. But ultimately, in QM, it's all about the math precisely because even the experts don't fully trust their intuitions, and so we keep getting back to Emmy Noether and her symmetries. (Unfortunately, the math behind those is extremely advanced, and I don't know a good way to simplify it.)
This isn't confined to physics, by the way. Economics suffers a similar problem. Almost everyone has an intuitive understanding of microeconomics, the kind of economic problem you run into in a household budget or setting prices for a store. Very few people without training understand macroeconomics, the kind of problem you run into in, for example, setting national funding levels. That's one reason, for example, that people are worried about excessive government spending in the United States; a lot of people think that the government will run out of money to pay off the national debt. This is ridiculous, since the government can conjure money at will, and so is no more likely to run out of money than the NBA is likely to run out of points in mid-season. ("I'm sorry, you just made a basket, but we can't give you two points for it because we're out of points.") But because people understand their household budget, they think the US federal budget runs the same way.
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They won't do that until they figure out how it works. After all, the last thing you want is to find out too late that the engines you just sent up generate black holes in zero gravity. And when you can't explain the physics behind how something works, you can't rule that out.I'll take it seriously the day they actually stick it on a probe and try it out...
And then if it works, I'll start demanding a Pluto orbiter.
Nah, you can rule that one out, no problem. There's still no such thing as a free lunch, and even if there is, that lunch is not going to weigh more than the sun.
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But ultimately, in QM, it's all about the math precisely because even the experts don't fully trust their intuitions, and so we keep getting back to Emmy Noether and her symmetries. (Unfortunately, the math behind those is extremely advanced, and I don't know a good way to simplify it.)From what I heard, Noether's equations are the simplified version.
If you think Noether's equations are simple, then I congratulate you.
Is it possible this is an area where quantum mechanics and relativity are acting in a manner that can only be modeled with a unified theory? Eventually, we would have to stumble across something like that.
Well, sure, it's possible, but I don't see any reason why this would be such an area.
There's not actually any indication that one is dealing with relativity-level speeds, energies, or forces in this experiment. I mean, I can generate milliNewtons of force -- substantially more milliNewtons of force than this drive -- simply by lifting my coffee cup, and I don't need relativity to explain it.
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I'm willing to bet it'll get vetoed because people who make the decision will jump to absurd conclusions about what's possible. Like I did. Just look at the LHC's controversies if you want an example of how far beyond reason people will jump.
And did the LHC get vetoed? Spoiler: It did not.