6 ms·

As always, the relevant XKCD: https://xkcd.com/955/ https://xkcd.com/955/ While I don't really believe it, I am intrigued by the possibility. It has been a lon

As always, the relevant XKCD: https://xkcd.com/955/ https://xkcd.com/955/ While I don't really believe it, I am intrigued by the possibility. It has been a long time since we learned anything truly new in physics. The recent breakthroughs (Higgs boson, gravitational waves, for example) were satisfying, but not surprising. I would desperately like to be surprised.

boyhowdy 10y ago
1. studies consistently are showing that this seems to produce thrust without expelling any matter 2. we know that can't be possible I think most people are excited about this not because they think we just proved 2 to be wrong, but instead because we know 2 must be true, so what the hell is going on with 1??? Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way.
- goodcanadian 10y ago
  By far the most likely scenario is that something subtle but utterly mundane is happening and no useful thrust is actually being produced. You say that: 1. studies consistently are showing that this seems to produce thrust without expelling any matter but this is in fact the first peer reviewed study, so we really only have a sample size of one (not to say other experiments are invalid, just that we have no reason to trust them). Even assuming it is down to subtle experimental error, we may still learn something interesting, of course. Far less likely is that this is actually producing useful thrust, and regardless of how it is doing it, that would be extremely interesting, and in all probability, new physics. Even if true, I don't expect it to completely overturn our understanding of physics, but it would be very exciting.
  - Fjolsvith 10y ago
    Here's another article that proposes to explain why it works: http://aip.scitation.org/doi/full/10.1063/1.4953807 http://aip.scitation.org/doi/full/10.1063/1.4953807
  - indolering 10y ago
    Others have tried to replicate the results but got thrust in the null position[0]. This indicates that the amount of thrust being generated is so small that it's likely the result of instrumentation error. [0]: https://tu-dresden.de/ing/maschinenwesen/ilr/rfs/ressourcen/dateien/forschung/folder-2007-08-21-5231434330/ag_raumfahrtantriebe/JPC---Direct-Thrust-Measurements-of-an-EM-Drive-and-Evaluation-of-Possible-Side-Effects.pdf?lang=en https://tu-dresden.de/ing/maschinenwesen/ilr/rfs/ressourcen/...
- flukus 10y ago
  > Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way. Most likely is still some sort of experimental error. I'd like it to be real but there is still tonnes of room for skepticism.
- indolering 10y ago
  >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 correct me if I am wrong, but that's ~1/100 the weight of a penny[0]. Even if they can produce these tiny amounts of of thrust reliably, they still need to eliminate other sources of error. Other false-positive results of similar devices have either generated thrust in the null condition or were later retracted after correcting for measurement error. >I think most people are excited about this not because they think we just proved 2 to be wrong, but instead because we know 2 must be true, so what the hell is going on with 1??? The EM drive literally entails perpetual motion. We know that's impossible, yet someone always manages to sell a new version of it every few years. >Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way. There is a reason this is in a journal dedicated to publishing experimental results from aerospace engineers and not a physics journal. Peer review isn't magic, it just means two out of three people signed off on a paper being published. [0]: Seems crazy small, math may be wacky off due to lack of sleep.
  - flukus 10y ago
    > The EM drive literally entails perpetual motion. We know that's impossible, yet someone always manages to sell a new version of it every few years. Well the universe was created, so that seems to imply the energy can be created. We don't know that energy can't be created, just that the current laws of the universe don't allow for it, as far as we know. Not that I believe this will violate that law in anyway. Even if the drive turns out to be real I suspect it will be something like photon entanglement, where it appears data is travelling faster than light but it's in no way helpful.
  - boznz 10y ago
    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.
Fjolsvith 10y ago
In case you missed it, the theory behind the EM Drive is also being used to explain galaxy rotation: https://www.researchgate.net/publication/313580454_Low-acceleration_dwarf_galaxies_as_tests_of_quantised_inertia https://www.researchgate.net/publication/313580454_Low-accel...
- fenollp 10y ago
  I don't know anything about this field but the language seems sound to me. Is there a consensus on this interpretation v. "just adding more dark matter"?
  - Fjolsvith 10y ago
    It is unfortunate that the theory of Dark Matter doesn't have a cute parlor trick like the EM Drive.
    - deleted 10y ago
      [deleted]
  - wfunction 10y ago
    > Is there a consensus on this interpretation v. "just adding more dark matter"? This reminded me of https://xkcd.com/1758/ https://xkcd.com/1758/
- the6threplicant 10y ago
  Why is it that EM advocates always seem to be dark matter-deniers? There's observational evidence for DM, a lot more than for the EM drive.
  - phs318u 10y ago
    > There's observational evidence for DM Um. Isn't that a contradiction in terms? By definition, DM is stuff whose existence is inferred by observations that contradict what we previously presumed to know. Hence postulate the existence of DM to close the gap between what we observe and what we "know".

boyhowdy 10y ago

1. studies consistently are showing that this seems to produce thrust without expelling any matter 2. we know that can't be possible I think most people are excited about this not because they think we just proved 2 to be wrong, but instead because we know 2 must be true, so what the hell is going on with 1??? Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way.

goodcanadian 10y ago
By far the most likely scenario is that something subtle but utterly mundane is happening and no useful thrust is actually being produced. You say that: 1. studies consistently are showing that this seems to produce thrust without expelling any matter but this is in fact the first peer reviewed study, so we really only have a sample size of one (not to say other experiments are invalid, just that we have no reason to trust them). Even assuming it is down to subtle experimental error, we may still learn something interesting, of course. Far less likely is that this is actually producing useful thrust, and regardless of how it is doing it, that would be extremely interesting, and in all probability, new physics. Even if true, I don't expect it to completely overturn our understanding of physics, but it would be very exciting.
- Fjolsvith 10y ago
  Here's another article that proposes to explain why it works: http://aip.scitation.org/doi/full/10.1063/1.4953807 http://aip.scitation.org/doi/full/10.1063/1.4953807
- indolering 10y ago
  Others have tried to replicate the results but got thrust in the null position[0]. This indicates that the amount of thrust being generated is so small that it's likely the result of instrumentation error. [0]: https://tu-dresden.de/ing/maschinenwesen/ilr/rfs/ressourcen/dateien/forschung/folder-2007-08-21-5231434330/ag_raumfahrtantriebe/JPC---Direct-Thrust-Measurements-of-an-EM-Drive-and-Evaluation-of-Possible-Side-Effects.pdf?lang=en https://tu-dresden.de/ing/maschinenwesen/ilr/rfs/ressourcen/...
flukus 10y ago
> Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way. Most likely is still some sort of experimental error. I'd like it to be real but there is still tonnes of room for skepticism.
indolering 10y ago
>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 correct me if I am wrong, but that's ~1/100 the weight of a penny[0]. Even if they can produce these tiny amounts of of thrust reliably, they still need to eliminate other sources of error. Other false-positive results of similar devices have either generated thrust in the null condition or were later retracted after correcting for measurement error. >I think most people are excited about this not because they think we just proved 2 to be wrong, but instead because we know 2 must be true, so what the hell is going on with 1??? The EM drive literally entails perpetual motion. We know that's impossible, yet someone always manages to sell a new version of it every few years. >Most likely we will find out that we are NOT violating the known laws of the universe, but we're "not violating" them in a very interesting way. There is a reason this is in a journal dedicated to publishing experimental results from aerospace engineers and not a physics journal. Peer review isn't magic, it just means two out of three people signed off on a paper being published. [0]: Seems crazy small, math may be wacky off due to lack of sleep.
- flukus 10y ago
  > The EM drive literally entails perpetual motion. We know that's impossible, yet someone always manages to sell a new version of it every few years. Well the universe was created, so that seems to imply the energy can be created. We don't know that energy can't be created, just that the current laws of the universe don't allow for it, as far as we know. Not that I believe this will violate that law in anyway. Even if the drive turns out to be real I suspect it will be something like photon entanglement, where it appears data is travelling faster than light but it's in no way helpful.
- boznz 10y ago
  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.

Fjolsvith 10y ago

In case you missed it, the theory behind the EM Drive is also being used to explain galaxy rotation: https://www.researchgate.net/publication/313580454_Low-acceleration_dwarf_galaxies_as_tests_of_quantised_inertia https://www.researchgate.net/publication/313580454_Low-accel...

fenollp 10y ago
I don't know anything about this field but the language seems sound to me. Is there a consensus on this interpretation v. "just adding more dark matter"?
- Fjolsvith 10y ago
  It is unfortunate that the theory of Dark Matter doesn't have a cute parlor trick like the EM Drive.
  - deleted 10y ago
    [deleted]
- wfunction 10y ago
  > Is there a consensus on this interpretation v. "just adding more dark matter"? This reminded me of https://xkcd.com/1758/ https://xkcd.com/1758/
the6threplicant 10y ago
Why is it that EM advocates always seem to be dark matter-deniers? There's observational evidence for DM, a lot more than for the EM drive.
- phs318u 10y ago
  > There's observational evidence for DM Um. Isn't that a contradiction in terms? By definition, DM is stuff whose existence is inferred by observations that contradict what we previously presumed to know. Hence postulate the existence of DM to close the gap between what we observe and what we "know".