36 ms·

Deep breaths. Probably experimental error. Extraordinary claims require extraordinary proof... God DAMN this is exciting.

pantalaimon 12y ago
As the article points out in 8., there have been previous, independent experiences that support the results.
- didgeoridoo 12y ago
  Well yes, without those it wouldn't even be worth talking about. I don't think the several experiments so far rise to the level of "extraordinary", but now that this is capturing so much attention, I don't doubt we'll get there soon.
- tobinfricke 12y ago
  These were other, earlier experiments, which the current experiment is attempting to duplicate. Importantly, while the new experiment has superficially "confirmed" the previous ones, it shows a much smaller effect. When the magnitude of the observed effect scales roughly with the margin of error of the experiment, one has very good reason to be skeptical ...
  - baq 12y ago
    they found 91 mmN of thrust and they claim their detector is sensitive to about 10mmN. that's almost an order of magnitude. this doesn't mean that it sounds too good to be true. edit: fixed units - dont have easy access to micro, thanks for pointing that out.
    - BugBrother 12y ago
      <Cough> You shocked me so much that I read the article! :-) (I follow the subject by browsing news now and then at http://talk-polywell.org/ http://talk-polywell.org/ which really is about the small fusion projects. That place should have more details then at Wired.) Use 'μ' for micro, 'm' is for milli.
    - tobinfricke 12y ago
      "u" is an acceptable replacement for "µ". I've never seen "milimili" (mm) before. You can spell it out, like "91 micronewtons". You can also use exponential notation like 91e-6 N or 91x10^(-6) N. To be fancy you can copy-and-paste unicode characters and write 91×10⁻⁶ N.
      - gambiting 12y ago
        I've seen "mm" used very frequently as millimetres. 1cm/2=5mm.
  - rsynnott 12y ago
    The previous tests were on an EmDrive, while the current one was a Cannae drive, which is a related but different design. The EmDrive guy claims the lower thrust is to be expected due to the design difference.
- keeperofdakeys 12y ago
  Just because something is able to be replicated multiple times, by different people, you still don't want to jump to conclusions. You just need to look back at polywater, http://www.slate.com/articles/health_and_science/science/2013/11/polywater_history_and_science_mistakes_the_u_s_and_ussr_raced_to_create.single.html http://www.slate.com/articles/health_and_science/science/201...
  - tobinfricke 12y ago
    And several other effects, like N-rays, filed by some under the category of "pathological science" (http://en.wikipedia.org/wiki/Pathological_science http://en.wikipedia.org/wiki/Pathological_science). There's also that nice graph of measurements of the speed of light versus time, in which experiments tended to reproduce the results of (erroneous) previous measurements, due to confirmation bias.
    - crusso 12y ago
      And Cold Fusion... ugh... I was at Georgia Tech in 1989 when they announced to the world that they had reproduced some aspects of the cold fusion experiment. So embarrassing. Reproducing an experiment, even with reputable scientists at NASA or reputable universities is in no way a guarantee.
- smackfu 12y ago
  The problem with these kind of unusual scientific results is often the experiment itself, not the results. It starts as "we do X, and it has a result of Z, and that makes no sense." Someone usually figures out that it's really "we do X (and Y), and it has a result of Z, and that is completely expected based on Y, and X is irrelevant as expected."
madaxe_again 12y ago
Indeed. As to the whole "we don't actually understand how it works" - we still can't make up our minds as to how wings work, so this isn't overly novel. Sure, we can explain the outcome, but whether it's Navier-Stokes or Bernoulli or something else, we can't make up our minds. I suspect this will be similar for a long while - although puts physics hat on I think this is likely a relativistic temporal quantisation effect.
- ColinWright 12y ago
  > ... we still can't make up our > minds as to how wings work, ... Interestingly, I recently spoke to an aerodynamicist and mentioned this, and I was severely lectured. In the follow-up he mellowed a little, but I suspect the "we" in your statement refers to laypersons who don't have advanced training in aeronautics, and yet claim to understand about flow pressure, Bernoulli, etc. I've been convinced that the people who genuinely work with these things and study them properly, actually do know how wings work. You may not, I may not, the mythical "man on the street" may not, but there are people who really, really do.
  - madaxe_again 12y ago
    No, I've a masters degree in Physics, and did several research projects on turbulent/laminar flow. We have a detailed understanding of a variety of theories which correctly represent the lift effect experienced on a body moving through a flow, yet none of them do it perfectly or completely. We can implement the technology well, but not without the aid of wind-tunnels and brute-force computer simulations in order to validate our designs - had we a perfect mathematical understanding of lift - we would not need to. Another example from Physics - quantum mechanics. We can describe the properties of a QM system, its outcomes based on inputs, the probabilities of states - yet we have not got the blindingest clue as to how it works. We have theories, but again, none are perfect - for instance see the Pilot Wave formulation of QM, which implies a deterministic universe, and isn't wrong, but isn't generally accepted - even though it describes QM systems well, for what little of it has been formulated in the last century.
    - 12y ago
tobinfricke 12y ago
I'd say that it's about on par with the faster-than-light neutrinos caper (tiny effect, violates known physics, probably result of experimental error, ...). Both would be very exciting if actually confirmed, but I personally found/find the chances too slim to (yet) get excited.
- antocv 12y ago
  Wasnt the faster-than-light neutrino myster solved? It was an optical cable not plugged in all the way.
  - ceejayoz 12y ago
    Yes. Unfortunately, that's likely to be a similarity here.
- deleted 12y ago
  [deleted]
- scott_s 12y ago
  Steven Novella (neurologist, active in the skeptical community) made a similar comparison: http://theness.com/neurologicablog/index.php/nasa-tests-em-drive/ http://theness.com/neurologicablog/index.php/nasa-tests-em-d...

pantalaimon 12y ago

As the article points out in 8., there have been previous, independent experiences that support the results.

didgeoridoo 12y ago
Well yes, without those it wouldn't even be worth talking about. I don't think the several experiments so far rise to the level of "extraordinary", but now that this is capturing so much attention, I don't doubt we'll get there soon.
tobinfricke 12y ago
These were other, earlier experiments, which the current experiment is attempting to duplicate. Importantly, while the new experiment has superficially "confirmed" the previous ones, it shows a much smaller effect. When the magnitude of the observed effect scales roughly with the margin of error of the experiment, one has very good reason to be skeptical ...
- baq 12y ago
  they found 91 mmN of thrust and they claim their detector is sensitive to about 10mmN. that's almost an order of magnitude. this doesn't mean that it sounds too good to be true. edit: fixed units - dont have easy access to micro, thanks for pointing that out.
  - BugBrother 12y ago
    <Cough> You shocked me so much that I read the article! :-) (I follow the subject by browsing news now and then at http://talk-polywell.org/ http://talk-polywell.org/ which really is about the small fusion projects. That place should have more details then at Wired.) Use 'μ' for micro, 'm' is for milli.
  - tobinfricke 12y ago
    "u" is an acceptable replacement for "µ". I've never seen "milimili" (mm) before. You can spell it out, like "91 micronewtons". You can also use exponential notation like 91e-6 N or 91x10^(-6) N. To be fancy you can copy-and-paste unicode characters and write 91×10⁻⁶ N.
    - gambiting 12y ago
      I've seen "mm" used very frequently as millimetres. 1cm/2=5mm.
- rsynnott 12y ago
  The previous tests were on an EmDrive, while the current one was a Cannae drive, which is a related but different design. The EmDrive guy claims the lower thrust is to be expected due to the design difference.
keeperofdakeys 12y ago
Just because something is able to be replicated multiple times, by different people, you still don't want to jump to conclusions. You just need to look back at polywater, http://www.slate.com/articles/health_and_science/science/2013/11/polywater_history_and_science_mistakes_the_u_s_and_ussr_raced_to_create.single.html http://www.slate.com/articles/health_and_science/science/201...
- tobinfricke 12y ago
  And several other effects, like N-rays, filed by some under the category of "pathological science" (http://en.wikipedia.org/wiki/Pathological_science http://en.wikipedia.org/wiki/Pathological_science). There's also that nice graph of measurements of the speed of light versus time, in which experiments tended to reproduce the results of (erroneous) previous measurements, due to confirmation bias.
  - crusso 12y ago
    And Cold Fusion... ugh... I was at Georgia Tech in 1989 when they announced to the world that they had reproduced some aspects of the cold fusion experiment. So embarrassing. Reproducing an experiment, even with reputable scientists at NASA or reputable universities is in no way a guarantee.
smackfu 12y ago
The problem with these kind of unusual scientific results is often the experiment itself, not the results. It starts as "we do X, and it has a result of Z, and that makes no sense." Someone usually figures out that it's really "we do X (and Y), and it has a result of Z, and that is completely expected based on Y, and X is irrelevant as expected."

madaxe_again 12y ago

Indeed. As to the whole "we don't actually understand how it works" - we still can't make up our minds as to how wings work, so this isn't overly novel. Sure, we can explain the outcome, but whether it's Navier-Stokes or Bernoulli or something else, we can't make up our minds. I suspect this will be similar for a long while - although puts physics hat on I think this is likely a relativistic temporal quantisation effect.

ColinWright 12y ago
> ... we still can't make up our > minds as to how wings work, ... Interestingly, I recently spoke to an aerodynamicist and mentioned this, and I was severely lectured. In the follow-up he mellowed a little, but I suspect the "we" in your statement refers to laypersons who don't have advanced training in aeronautics, and yet claim to understand about flow pressure, Bernoulli, etc. I've been convinced that the people who genuinely work with these things and study them properly, actually do know how wings work. You may not, I may not, the mythical "man on the street" may not, but there are people who really, really do.
- madaxe_again 12y ago
  No, I've a masters degree in Physics, and did several research projects on turbulent/laminar flow. We have a detailed understanding of a variety of theories which correctly represent the lift effect experienced on a body moving through a flow, yet none of them do it perfectly or completely. We can implement the technology well, but not without the aid of wind-tunnels and brute-force computer simulations in order to validate our designs - had we a perfect mathematical understanding of lift - we would not need to. Another example from Physics - quantum mechanics. We can describe the properties of a QM system, its outcomes based on inputs, the probabilities of states - yet we have not got the blindingest clue as to how it works. We have theories, but again, none are perfect - for instance see the Pilot Wave formulation of QM, which implies a deterministic universe, and isn't wrong, but isn't generally accepted - even though it describes QM systems well, for what little of it has been formulated in the last century.
  - 12y ago

tobinfricke 12y ago

I'd say that it's about on par with the faster-than-light neutrinos caper (tiny effect, violates known physics, probably result of experimental error, ...). Both would be very exciting if actually confirmed, but I personally found/find the chances too slim to (yet) get excited.

antocv 12y ago
Wasnt the faster-than-light neutrino myster solved? It was an optical cable not plugged in all the way.
- ceejayoz 12y ago
  Yes. Unfortunately, that's likely to be a similarity here.
deleted 12y ago
[deleted]
scott_s 12y ago
Steven Novella (neurologist, active in the skeptical community) made a similar comparison: http://theness.com/neurologicablog/index.php/nasa-tests-em-drive/ http://theness.com/neurologicablog/index.php/nasa-tests-em-d...