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> Lots of people make extraordinary claims about new theories or perpetual motion machines. Such claims don't often get replicated by multiple, independent lab

by maaku 10y ago

> Lots of people make extraordinary claims about new theories or perpetual motion machines. Such claims don't often get replicated by multiple, independent labs, as is the case here.

moron4hire 10y ago
And they seem to be basing their work on "Einstein was right, we just didn't fully understand what it meant."
crusso 10y ago
I'm not up on every instance of "replication" -- but so far, the ones I've read about have been really shoddily performed. http://io9.gizmodo.com/no-german-scientists-have-not-confirmed-the-impossibl-1720573809/1720737686 http://io9.gizmodo.com/no-german-scientists-have-not-confirm... I'd love for this phenomenon to be real, but the Technology Review article did not present a realistic picture of the verification attempted to date.
- austinz 10y ago
  I am skeptical about the EmDrive (although I would very much like it to be real), and my opinion on the drive or its theoretical underpinnings is not really relevant, given my lack of knowledge about the field. But I don't think that writeup is very good either: From the IO9 article: > The experimental setup is so flawed that it’s continuing to produce measurable “thrust” while in null mode when it should do nothing. From the Wikipedia page on RF resonant cavity thrusters (and corroborated by the citations): > the 'null test article', was designed without the internal slotting that the Cannae Drive's creator theorised was necessary to produce thrust > The null test device was not intended to be the experimental control. The article's author seems to fundamentally misunderstand the purpose of the null test setup. Setting everything else aside, if the null articles did produce thrust, this would disprove the Cannae theory (which requires the slotted configuration), but would say nothing about the efficacy of RF thrusters in general. Their quotes from various physicists about why the drive is probably nonsense are a lot more compelling.
  - DavidSJ 10y ago
    Pardon my ignorance, but I don't think anyone seriously doubts that the null article produces no thrust. So it's not a question of whether the null article's production of thrust disproves the efficacy of anything. It's a question of whether the experimental setup which measured that thrust is trustworthy.
    - taneq 10y ago
      Holy triple negative batman! Do you mean that nobody thinks the null article produces thrust? Or did I parse that wrong?
      - DavidSJ 10y ago
        You have the right parity but there is a slight semantic difference between that and what I said. Sorry that I wasn't so clear. I'll try again. There's a difference between "I don't believe X" (which allows for ambivalence) and "I believe not X" (which does not). There's also a difference between "I believe not X" and "I have no doubt of not X". I was pointing out that there is no dispute or even doubt about the null article's inability to produce thrust (and this would have been a better phrasing). So the question is not "what does the null article's thrust imply about various hypotheses?" It's "what does the apparatus' measurement of thrust from the null article imply about the apparatus?" GP seems to have missed this point.
        taneq 10y ago
        Agreed on the semantic differences, I missed that one. > "What does the apparatus' measurement of thrust from the null article imply about the apparatus?" That makes sense, and I think it's a good question. Thanks for clarifying!
    - austinz 10y ago
      I'm not saying the experiments were trustworthy or conducted properly. Only that the author of the article misunderstood the experimental setup. (To be precise, the comment about the null thruster was made by the author in a comment on this article, and by a previous article written by the author, which this one references. It is not in the article itself.)
mcnamaratw 10y ago
If you read the papers, the claims are not very well backed by independent experiment. (The claims are 'replicated' meaning lots of people repeat them!) There's little data and what there is is right at the limit of measurement error. Results from different groups conflict wildly. Tech Review is a PR rag, not a scientific publication.

by maaku 10y ago

> Lots of people make extraordinary claims about new theories or perpetual motion machines. Such claims don't often get replicated by multiple, independent labs, as is the case here.

moron4hire 10y ago

And they seem to be basing their work on "Einstein was right, we just didn't fully understand what it meant."

crusso 10y ago

I'm not up on every instance of "replication" -- but so far, the ones I've read about have been really shoddily performed. http://io9.gizmodo.com/no-german-scientists-have-not-confirmed-the-impossibl-1720573809/1720737686 http://io9.gizmodo.com/no-german-scientists-have-not-confirm... I'd love for this phenomenon to be real, but the Technology Review article did not present a realistic picture of the verification attempted to date.

austinz 10y ago
I am skeptical about the EmDrive (although I would very much like it to be real), and my opinion on the drive or its theoretical underpinnings is not really relevant, given my lack of knowledge about the field. But I don't think that writeup is very good either: From the IO9 article: > The experimental setup is so flawed that it’s continuing to produce measurable “thrust” while in null mode when it should do nothing. From the Wikipedia page on RF resonant cavity thrusters (and corroborated by the citations): > the 'null test article', was designed without the internal slotting that the Cannae Drive's creator theorised was necessary to produce thrust > The null test device was not intended to be the experimental control. The article's author seems to fundamentally misunderstand the purpose of the null test setup. Setting everything else aside, if the null articles did produce thrust, this would disprove the Cannae theory (which requires the slotted configuration), but would say nothing about the efficacy of RF thrusters in general. Their quotes from various physicists about why the drive is probably nonsense are a lot more compelling.
- DavidSJ 10y ago
  Pardon my ignorance, but I don't think anyone seriously doubts that the null article produces no thrust. So it's not a question of whether the null article's production of thrust disproves the efficacy of anything. It's a question of whether the experimental setup which measured that thrust is trustworthy.
  - taneq 10y ago
    Holy triple negative batman! Do you mean that nobody thinks the null article produces thrust? Or did I parse that wrong?
    - DavidSJ 10y ago
      You have the right parity but there is a slight semantic difference between that and what I said. Sorry that I wasn't so clear. I'll try again. There's a difference between "I don't believe X" (which allows for ambivalence) and "I believe not X" (which does not). There's also a difference between "I believe not X" and "I have no doubt of not X". I was pointing out that there is no dispute or even doubt about the null article's inability to produce thrust (and this would have been a better phrasing). So the question is not "what does the null article's thrust imply about various hypotheses?" It's "what does the apparatus' measurement of thrust from the null article imply about the apparatus?" GP seems to have missed this point.
      - taneq 10y ago
        Agreed on the semantic differences, I missed that one. > "What does the apparatus' measurement of thrust from the null article imply about the apparatus?" That makes sense, and I think it's a good question. Thanks for clarifying!
  - austinz 10y ago
    I'm not saying the experiments were trustworthy or conducted properly. Only that the author of the article misunderstood the experimental setup. (To be precise, the comment about the null thruster was made by the author in a comment on this article, and by a previous article written by the author, which this one references. It is not in the article itself.)

mcnamaratw 10y ago

If you read the papers, the claims are not very well backed by independent experiment. (The claims are 'replicated' meaning lots of people repeat them!) There's little data and what there is is right at the limit of measurement error. Results from different groups conflict wildly. Tech Review is a PR rag, not a scientific publication.