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this thrust was not predicted by physicists. We have a repeatable non zero result where the prediction was zero. We also don't know how much it can be scaled o

this thrust was not predicted by physicists. We have a repeatable non zero result where the prediction was zero. We also don't know how much it can be scaled or improved.

ceejayoz 10y ago
Experimental errors are very much predicted by physicists, though. https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly https://en.wikipedia.org/wiki/Faster-than-light_neutrino_ano...
danbruc 10y ago
No, we don't have a non-zero measurement where the prediction was a zero measurement. There are all kind of possible source of parasitic effects, especially because the measured signal is so close to the noise floor. The prediction for the ideal experiment is zero, actually it probably is not due to the impulse of the emitted photons, but for the real experiment the prediction is certainly not zero and the paper discuses and compensates for various parasitic effects.
- kashkhan 10y ago
  i assume that this result is notable because they made all the needed corrections and took into account all known phenomena. Like serious scientists would.
  - danbruc 10y ago
    They accounted for everything they could think of an that the experimental setup allowed to. It is still very much more likely that they missed at least one source of error than that our understanding of physics is wrong in such a serious way. Not that it is totally impossible that the effect is real, it just is still very, very unlikely.
    - taneq 10y ago
      Well that's why you publish research, isn't it? They accounted for everything they could think of, now they're giving everyone else a chance to spot mistakes.
      - danbruc 10y ago
        Yes, of course. I never wanted to attack the paper in any way, I am just trying to say that this positive result will almost certainly turn out to be wrong and one should not draw the wrong conclusion that this is any kind of proof.
  - cygx 10y ago
    As did the OPERA guys, and yet a fiber optic cable attached improperly slipped through.
lutusp 10y ago
> We have a repeatable non zero result ... Yes, but they aren't sure what they're measuring. Remember that science (and Occam's razor) requires us to apply the most pedestrian explanations first, like some overlooked experimental error, not new physics. The "new physics" explanation should be the last possibility considered, not the first. This similar study comes to a much less encouraging conclusion (the abstract acurately summarizes the study): 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/...
- kashkhan 10y ago
  the only reason HN is discussing this result is that it is unexpected. The point of the experiment is to zero out all pedestrian explanations. Occam's razor is a good guide, but it is not a rule the universe is obliged to follow.
  - TeMPOraL 10y ago
    > Occam's razor is a good guide, but it is not a rule the universe is obliged to follow. It seems to be, actually, because the rule follows straight from probability theory :). > The point of the experiment is to zero out all pedestrian explanations. Doesn't mean they did account for all of them. But that's why they're publishing. They've done all they could, they still get the unexpected effect, so it's time for other researchers to try it and at some point we will finally determine whether it's an error or new physics :).

this thrust was not predicted by physicists. We have a repeatable non zero result where the prediction was zero. We also don't know how much it can be scaled or improved.

ceejayoz 10y ago

Experimental errors are very much predicted by physicists, though. https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly https://en.wikipedia.org/wiki/Faster-than-light_neutrino_ano...

danbruc 10y ago

No, we don't have a non-zero measurement where the prediction was a zero measurement. There are all kind of possible source of parasitic effects, especially because the measured signal is so close to the noise floor. The prediction for the ideal experiment is zero, actually it probably is not due to the impulse of the emitted photons, but for the real experiment the prediction is certainly not zero and the paper discuses and compensates for various parasitic effects.

kashkhan 10y ago
i assume that this result is notable because they made all the needed corrections and took into account all known phenomena. Like serious scientists would.
- danbruc 10y ago
  They accounted for everything they could think of an that the experimental setup allowed to. It is still very much more likely that they missed at least one source of error than that our understanding of physics is wrong in such a serious way. Not that it is totally impossible that the effect is real, it just is still very, very unlikely.
  - taneq 10y ago
    Well that's why you publish research, isn't it? They accounted for everything they could think of, now they're giving everyone else a chance to spot mistakes.
    - danbruc 10y ago
      Yes, of course. I never wanted to attack the paper in any way, I am just trying to say that this positive result will almost certainly turn out to be wrong and one should not draw the wrong conclusion that this is any kind of proof.
- cygx 10y ago
  As did the OPERA guys, and yet a fiber optic cable attached improperly slipped through.

lutusp 10y ago

> We have a repeatable non zero result ... Yes, but they aren't sure what they're measuring. Remember that science (and Occam's razor) requires us to apply the most pedestrian explanations first, like some overlooked experimental error, not new physics. The "new physics" explanation should be the last possibility considered, not the first. This similar study comes to a much less encouraging conclusion (the abstract acurately summarizes the study): 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/...

kashkhan 10y ago
the only reason HN is discussing this result is that it is unexpected. The point of the experiment is to zero out all pedestrian explanations. Occam's razor is a good guide, but it is not a rule the universe is obliged to follow.
- TeMPOraL 10y ago
  > Occam's razor is a good guide, but it is not a rule the universe is obliged to follow. It seems to be, actually, because the rule follows straight from probability theory :). > The point of the experiment is to zero out all pedestrian explanations. Doesn't mean they did account for all of them. But that's why they're publishing. They've done all they could, they still get the unexpected effect, so it's time for other researchers to try it and at some point we will finally determine whether it's an error or new physics :).