3 ms·

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."

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."