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NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

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Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#61

Post by consp »

simonh wrote: post #33
Sanddancer wrote: post #32

Earlier quoted context omitted.

Those forces are actually pretty well behaved and can be readily measured and accounted for. Also, light sails have a order of magnitude less power, and the Pioneer Anomaly [1] was smaller yet. Space is probably the best place to test something like this. [1] https://en.wikipedia.org/wiki/Pioneer_anomaly

The Pioneer Anomaly was only detectable over several decades and a journey to the furthest reaches of the solar system. I'd expect a useful propulsion system to produce effects quite a bit more detectable than that. This effect is about 1/25 the power efficiency of the lowest power ion thrusters. Output at this level over a very long period might be useful at the interplanetary level and maybe at geostationary altitu…

Wouldn't variations in atmospheric drag negate any possibility of detecting the actual thrust component in leo? The trusts are small, as is the device, but any variation would be extremely hard to detect and measure. Please correct me if my line of thinking is wrong though, I'm not an aerospace engineer.

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#62

Post by DanielBMarkham »

akvadrako wrote: post #59
DanielBMarkham wrote: post #47

Earlier quoted context omitted.

I've been following along on reddit on several subs, including the EMDrive sub. This is a fascinating study about the politics and social aspect of science -- i.e., how it's actually done. I'm just a layman, but so far it looks like this is experimental error. I never knew there were so many ways to screw something like this up! Having said that, this is a win either way. It teaches all of us about rigorous science,…

I agree this incident has educational value, because it's like a toy research project. The science behind the EM drive and the means to understand why it could never work are accessible to laymen who only have to trust our most well-tested physical laws. If you're curious, you can find an easy to understand theory about why breaking the conservation of momentum lets you build a perpetual-motion machine, creating infi…

Yeah, but it's more than just getting the natural laws out and beating people over the head with them -- there's emotional involvement from the public, and that's terrific.

For instance, there are quite a few hobbyests that are building their own rigs. There's discussion about noise control, radiation leakage, resonance, and so forth.

For the more theory-minded, there's a great discussion about empirical data versus theory, which you allude to. At the end of the day, of course, if you've got data, you've got data. Once the errors are taken out of the system, observation beats theory hands-down.

I know scientists would probably much rather have a conversation around "This is science, dang it, go read a book!" but for us layman schmucks, the really cool part is a conversation around "This is why science is what it is"

(Note: I'm not addressing you directly. I've just noticed a lot of mockery and impatience from some of the scientific community, and that's a shame. Better to use this as a teaching moment in my opinion)

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#63

Post by akvadrako »

boznz wrote: post #52
indolering wrote: post #27

Earlier quoted context omitted.

>studies consistently are showing that this seems to produce thrust without expelling any matter Nope, others have been unable to reproduce their results. As for Eagle Works ... their data is crap. The paper consists of 18 data points and large amounts of variance. The largest thrust measurement comes from the middle power setting. Furthermore, they are measuring (at most!) 120 micro-newtons of thrust. Someone correc…

I'm not a scientist but it begs the question, how is 1.2milinewtons for 1KW input perpetual motion ? The only way it could be Perpetual motion I can see is if I could somehow generate 1KW with that 1.2milinewtons which would be science fiction.

Basically, it's because as the drive keeps accelerating without losing mass, the velocity is proportional to the energy expended. However, it's kinetic energy increases with the velocity squared. Eventually, there is a cross-over point.

You can create infinite energy by placing a bunch of drives on the spokes of a huge flywheel.

See this paper for a more detailed answer:

https://arxiv.org/abs/1506.00494

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#65

Post by Jedd »

throwanem wrote: post #56
f4rker wrote: post #43

Earlier quoted context omitted.

This is the worst part of the internet. Amateurs and 2nd year college students dismissing months/years of hard work by actual professionals​. They take all this work and "hand wave" it away in less time than it takes to make coffee. The internet is full of amateurs and they are very very confident about their abilities.

Professionals don't always get things right, either, and reactionless thrust doesn't really fit into our best current physical model. That doesn't mean it can't exist - but, given the general usefulness of our current model in predicting how things will behave, there's reasonable cause for extraordinary skepticism in response to claims that one of its "can't happen" conditions is inaccurate. Maybe the paper's conclus…

I totally understand some scepticism, but there appears to be the archetypal response of 'Oh, I bet NASA hasn't thought of this ...' when it's inconceivable that NASA hasn't, in fact, thought of that.

Some of the most sensible comments I've seen here have basically said 'It seems to violate what we know of physics, so hopefully it's right and we have some interesting times ahead'.

It's the dismissal, out of hand, after a relatively extensive amount of research and study -- especially compared to what the armchair critics can supply -- that I find frustrating.

Yeah, sure, I get that it seems implausible, but it transcends hubris to know that it's simply experimental error.

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#66

Post by Oletros »

Jedd wrote: post #40

NASA has published this paper. These guys presumably know what they're talking about. Moon landing, space shuttle, Voyager, etc. They ran actual experiments on this drive. Why are half the comments here saying 'They must be wrong' - seemingly based on nothing more than a strong belief that NASA must be wrong.

> Why are half the comments here saying 'They must be wrong' - seemingly based on nothing more than a strong belief that NASA must be wrong.

Nothing more than a strong believe?

Extraordinary claims need extraordinary proof and the paper doesn't have too much quality regarding the data.

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#67

Post by colorint »

DanielBMarkham wrote: post #62
akvadrako wrote: post #59

Earlier quoted context omitted.

I agree this incident has educational value, because it's like a toy research project. The science behind the EM drive and the means to understand why it could never work are accessible to laymen who only have to trust our most well-tested physical laws. If you're curious, you can find an easy to understand theory about why breaking the conservation of momentum lets you build a perpetual-motion machine, creating infi…

Yeah, but it's more than just getting the natural laws out and beating people over the head with them -- there's emotional involvement from the public, and that's terrific. For instance, there are quite a few hobbyests that are building their own rigs. There's discussion about noise control, radiation leakage, resonance, and so forth. For the more theory-minded, there's a great discussion about empirical data versus…

>Once the errors are taken out of the system, observation beats theory hands-down.

But how do you go about distinguishing signal from noise? That's ultimately the reason data say far less, on their own, than they seem to: because interpretation of data is at least as important as how you collect them, but interpretation brings in all the gooey things people really want to wish away. Or put more bluntly, observation can't "beat" theory, because theory is the way you decide which observations to make, how to carry out those observations, and how to understand the products of the observation. Theory and observation are inseparable; in a sense, all observation is at once theoretical, and all theory is at once observational.

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#68

Post by Oletros »

DanielBMarkham wrote: post #62
akvadrako wrote: post #59

Earlier quoted context omitted.

I agree this incident has educational value, because it's like a toy research project. The science behind the EM drive and the means to understand why it could never work are accessible to laymen who only have to trust our most well-tested physical laws. If you're curious, you can find an easy to understand theory about why breaking the conservation of momentum lets you build a perpetual-motion machine, creating infi…

Yeah, but it's more than just getting the natural laws out and beating people over the head with them -- there's emotional involvement from the public, and that's terrific. For instance, there are quite a few hobbyests that are building their own rigs. There's discussion about noise control, radiation leakage, resonance, and so forth. For the more theory-minded, there's a great discussion about empirical data versus…

> Once the errors are taken out of the system, observation beats theory hands-down.

But it seems that not all errors have not been taken out of the system

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#69

Post by vorotato »

f4rker wrote: post #43
Jedd wrote: post #40

NASA has published this paper. These guys presumably know what they're talking about. Moon landing, space shuttle, Voyager, etc. They ran actual experiments on this drive. Why are half the comments here saying 'They must be wrong' - seemingly based on nothing more than a strong belief that NASA must be wrong.

This is the worst part of the internet. Amateurs and 2nd year college students dismissing months/years of hard work by actual professionals​. They take all this work and "hand wave" it away in less time than it takes to make coffee. The internet is full of amateurs and they are very very confident about their abilities.

Lets be clear here, the people who ran published this test are also skeptical about this. However they did everything possible to reduce and remove errors from their calculations. This means one of two things, either our present understanding of physics is incorrect, or our present understanding of experimental physics and the ways errors creep into our experiments is incomplete. The scientists who did this test suspect the latter, however they've done everything they know to remove mistakes. Much like when we are troubleshooting why our computer won't start we don't jump to the CPU is dead, they also don't just jump to the big conclusion. It's still neat though because we'll still learn something meaningful, and you never know it really could open new understanding of reality.

Re: NASA's Peer-Reviewed EM Drive Paper Has Finally Been Published

#70

Post by boznz »

akvadrako wrote: post #63
boznz wrote: post #52

Earlier quoted context omitted.

I'm not a scientist but it begs the question, how is 1.2milinewtons for 1KW input perpetual motion ? The only way it could be Perpetual motion I can see is if I could somehow generate 1KW with that 1.2milinewtons which would be science fiction.

Basically, it's because as the drive keeps accelerating without losing mass, the velocity is proportional to the energy expended. However, it's kinetic energy increases with the velocity squared. Eventually, there is a cross-over point. You can create infinite energy by placing a bunch of drives on the spokes of a huge flywheel. See this paper for a more detailed answer: https://arxiv.org/abs/1506.00494

My argument still stands you cannot ever reach such a cross-over point at the milli-newton/KW scale. If they call a much bigger fraction then we can call BS
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