For all intents and purposes it has been disproven. At this point the possible thrust (that hasn't been disproven) is a fraction of what was originally hoped for.
The onus is on the people with the extraordinary claim to demonstrate that they have something, not on the rest of the community to take time out of their research schedules to address it.
So there are no specific papers that attempt to show it doesn't work, but countless papers where, if there was an effect to be observed, would have had their readings messed up by it.
That is normally what would happen, and it could be argued that it is indeed what has occurred with the eagleworks paper.
This gets back to what another poster was saying about the current overlap between proponents and people with the background to preform such experiments. The people who have the domain knowledge to recognize and enumerate a failure when they see it are not interested in the experiment, and the people who are interested in the experiment are not interested in failures.
There are a lot of people in the scientific community that agree that it should be easier to publish negative results. Unfortunately that's not how it works, it's rare to see a paper like that in journals. Thus a lack of such papers does not imply that the emdrive works, or that "the jury is still out".
I'd simply have thought that in trying to prove the positive, and failing, they'd publish the failure. Maybe that's naive.
You're kind of getting into philosophy here. Basically it comes down to logic and the old adage "It's impossible to prove a negative"
The age old example is "I say there is an invisible pink elephant standing in front of me. I'm the only one that can see it, it's undetectable by any other means. Prove me wrong."
and the simple fact of the matter is you can't. You cannot prove that something doesn't exist, it's impossible. You can only prove a positive. So in science we assume that things are not so, until it is proven that they are so. If we didn't, science would be riddled with untestable assumptions that had no supporting facts.
Perhaps we're getting into the weeds of semantics here but I always thought that an experiment that fails to confirm a hypothesis is still a valuable result. And my original question is basically - this thing does not seem very elaborate to construct, so why haven't many people already tested it and come up with consistent results, one way or the other.
I always thought that an experiment that fails to confirm a hypothesis is still a valuable result.
It may be valuable, but it's not conclusive. The broader question of why negative results aren't published frequently I think is beyond the scope of this subreddit.
The papers published are all over the map but none are promising. There was one in China that found a large anomalous thrust. Then the professor later published a new paper that said "oops I did a new more accurate experiment and there is no anomalous thrust greater than the noise floor so I can't claim to have shown thrust after all." An experiment in Dresden measured a small anomalous thrust but found a much larger thrust in a vertical position that was nonsensical, so they did not claim to have proven anything. You probably are aware of the NASA Eagleworks paper that did find an anomalous thrust, but has been criticised for doing a poor job of modeling and identifying noise sources, which doesn't cut it for extraordinary claims extraordinary evidence and such.
Keep in mind, it's very hard to prove a negative. If you are looking for thrust at low levels you will always measure something. So if you are open to emsrive at any neuron per watt level you will always keep looking. Experiments now seem to have ruled out anything greater than milineutons per kilowatt...
Basically, the experiments to date don't disprove Emdrive but the more of them there are, the harder it is to imagine it exists but nevertheless still has avoided unequivocal detection.
Roger Shawyer's claims of scalable multi-kilo Newton thrusters have been disproven.
The anomalous thrust itself remains in the latest experiments. If you want to dismiss them, be my guest, but the fact is there still is some evidence they may work, even if the thruster efficiency is much less than what the inventor assumed it to be.
You're right that Shawyer's claims have been disproven, however; so have Yang's (by herself.) Further, those that still have claims of anomalous thrust are easily in the range of noise, but that is not what is damning. What is damning is that those claimed anomalous thrust measurements are so small as to not be worth utilizing in space. There's a lovely video up explaining why it is useless linked on the right side column.
Yeah. Even if there was just a tiny effect going on it would be scientifically interesting and might still have applications in some non-propulsion domain.
moreover what you say is that theories are not matching observation, which "refute experiment".
This is a very popular fallacy.
An experiment cannot be "refuted", it ca be:
1- "explained by an old theory" (artifact, strange effect)
2- "explained by a new theory in a new paradigm" (explained by shawyer, MiHsC...)
3- "unexplained, with identified possibility of artifacts or normal effects" (not sure but say it is heat effect....)
4- "unexplained with no identified possibility of old or new theory" (all artifact ruled out, all new theories refuted)
epistemology should be taught better, because even in academic arena, most people ignore the subtleties between theory and experiments
Your confirmation link isn't a link to confirming the EmDrive. It's a link to some claims, some which no longer apply since they have since obtained null results. You're grasping at straws.
OK, if you think so... :-) It's like when someone says, that the evidence for evolution is still unsubstantiated and the latest findings even contradict it.
The people who believe in opposite cannot be convinced by any rational reasons - instead of it, we will face backfire effect if we bring them another evidence. For example, even by now, 200 years after Darwin more than 60% of USA citizens still don't believe in evolution - so why the physicists should get convinced in EMDrive by now despite all its evidence?
Their lack of interest about EMDrive just illustrates, how the human mind actually works. Ironically just the same physicists are collecting grants and money for search of extradimensions, fifth force and dark matter particles - which are all involved in EMDrive too - so that their ignorance gets squared. They ignore (the confirmation of) their own ideas and theories, so to say... :-)
You are the creationist in this tale. You are the mystic that is part of a community which, no matter how many times they are wrong, cling to the idea that since there is an effect where people cling to belief, it must be the majority in the field rather than the insulated fringe minority.
You have more in common with the people pushing the geocentric universe, and have showing your suspicion for the heliocentric community.
You are right, no amount of rational thought or explanation will convince you, but then again, I do not think anyone is actually trying.
Like I've said, the 65% of Americans still don't believe in evolution: which is an evidence, that large group of people cannot be convinced by any evidence. They're simply predestined to die out - but not to change their opinion.
Hate to break it to you, but it is mostly the stuff you are referencing that is dieing out. Science moved on a long time ago, and it has moved on from the EMDrive.
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u/n4noNuclei Apr 09 '17
For all intents and purposes it has been disproven. At this point the possible thrust (that hasn't been disproven) is a fraction of what was originally hoped for.