That being said, I still think it's wrong of mainstream science immediately reject Cold Fusion/LENR or even Em Drive research.
Just take it for what it is, an anomaly. Which may or may not lead to a breakthrough.
All the reports of the Em Drive are not conclusive. The force that they are measuring is very small and very close to the experimental error. It looks more like involuntary p hacking that a good incontrovertible experiment.
I was not following the resents advances of the LENR. IIRC they heat a device with an electric current and they estimate how much heat it release. Measuring heat is a very difficult task, so the measurements are problematic. The additional heat is not too much. They don't have a device that can autosubstain the reaction, and that can silence all the critics.
If you want an to see how the physic community reacts to an anomaly, consider the high temperature superconductors. They are clearly impossible, well at least unbelievable, and the old theory forbid them. But 20 years ago they gave a foolproof method to build a high temperature superconductors in a good lab. The experiments were conclusive. You can even tweak the recipe and get a better superconductor. You can put them under high pressure and get more temperature. You can make many experiments with them. But still there is no good theory to explain how they work. Someone told me that the explanation was flux pinning, but apparently it still disputed and perhaps that explanation is wrong. But anyway, in spite there is no good theoretical explanation, you can make conclusive experiments with an relatively easy to build superconductor and some liquid nitrogen.
Mainstream physics love anomalies. You can get a Nobel price for confirming or explaining it. You can enclose a few graduate students to study it. You can get money from grants. But you must have to ensure a minimal probability that the anomaly is real, because you must release the graduate students someday ...
I believe what makes it so hard to tell is the labelling of any cold fusion researcher as a crackpot, which seems to have forced it 'underground'. Certainly a valid social experiment in physics if nothing else!
In my opinion any empirical data that has no currently obvious explanation should be called an "anomaly" until one is found. It doesn't matter how unlikely the Em Drive interacting with some ether or how low the thrust might be, the observed thrust is still an anomaly until you can find and confirm the actual cause. In the case of cold fusion, it was a mistake to (impolitely!) dismiss that anomaly without any obvious proof of the real cause. I have no idea about the current state of this research or whether it will ever pan out, but I am confident in saying that much.
And yes, this means we all need to have a much healthier, more skeptical, and less emotional response to reports of "anomalies" in the news.
There's something in the data that you don't understand, and you don't know where it comes from. Sometimes you find it's a bug in the setup, and other times you realize it's already known physics. Part of the time you just don't pursue it further, because there's no time and money to do this for everything. Especially, if it's a small signal down at the noise floor and you are not in full control of the measurement so that it's likely to be a bug in any case, there's no point to pursue it further.
There's nothing to get excited about in emdrive. There's no theoretical reason to expect the device does anything. The experimental data is likely to be just systematic error. Other groups that published results (TU Dresden, NWPU) in the end failed to reproduce the effect, and concluded they found zero result within the bounds of measurement error. It is very plausible this is the case also for the eagleworks measurement, so saying there is "observed thrust" is likely scientifically misleading.
And the way you solve that is by experimenting, experimenting again and trying new approaches to the problem
Once it survives a couple of experiments, then you can say there might be something there
(Besides analysis of the experiment to try to eliminate errors on the design, but that's not possible for all kinds of errors)
The downfall of many interesting lines of inquiry.
They've also tested joining segments of tape together in joints, and found it doesn't add enough resistance to matter. So their design is modular and can easily be taken apart every year to replace the core, which basically solves the problem of damage from neutron radiation.
If the Em Drive works, it invalidates a lot of mathmatical equalities that are derived from the fact that electro-magnetism works through fields. So you're basically invalidating the fundamental nature of electro-magnetism, not "just" conservation of energy
I think a lot of those rejections are coming from the crazy claims the EM drive inventor is making, everything from free energy to flying cars.
If you stick to the pure experimental aspects of "we put a microwave in a can and obtained these anomalous results" and ignore everything else, there's something interesting there that bears investigation.
This kind of "ringdown" effect can be observed at human-compatible timescales at low HF frequencies in crystal resonators. But only a fast oscilloscope will let you observe it in a cavity.
But it's premature to speculate on what might be happening at that level of detail.
Just speculating.
You could get similar charts between the EM drive cooling off as a boat slows down.
The graphed shape of how that thrust tails off is just a little part of that. Pointing at it does not help resolve the big problem.
At this stage I don't think you can claim the measurements are obviously wrong without actually calculating heat loss rates and how heat expansion would affect measurement with the given equipment asymmetries.
For sure, we should spend money to validate the EM-drive, but push back against funding going to all-out "free energy" without a lot more proof.
Einstein GR postulate number one: microscopic physics is background-independent.
These experiments' microscopic details behave the same on Earth, on the moon, and in the ISS, but their macroscopic behaviours sure don't. You have to input details of the local structure of spacetime into each of them if you want to predict their results (e.g., what trajectory the walk takes, or how long it takes for a ball to reach the bottom of a depression in the rubber sheet) successfully.
Heck, TQFTs in 2+1D are still under active research (and are behind Microsoft's quantum computer efforts).
General relativity would also be incomplete in this sense. It fails to describe quantum phenomena.
A better approach is to say that, to describe fundamental things in nature, what we have now is a patchwork of independent theories that are not quite meshing with each other.
Study of perturbatively quantized gravity is precisely why we know that General Relativity is not renormalizable by power-set counting in strong gravity, and precisely why we have a good definition for strong gravity (more than one loop of gravitons in a Feynman diagram) and also why we have a good idea about where to expect strong gravity (very close to the centre of mass-momentum of a black hole, and very close to the big bang).
Although the behaviour of arbitrarily high energy and high density matter may be found in a very different theory from General Relativity, there is no presently known reason why approaches involving renormalization group flow (e.g. asymptotically safe gravity) cannot "save" perturbatively quantized gravity by providing a renormalization scheme that works into the UV limit. One could likewise point to GUT programmes and say that at those energy scales a theory very different from the Standard Model will be more useful.
In the meanwhile, perturbatively quantized gravity is a perfectly good effective field theory, in the sense of the work by Kenneth G Wilson.
The point you're replying to is better addressed this way: the Standard Model doesn't even properly consider gravity, and it simply does not need to if in the UV completion of General Relativity you can recover the Minkowski metric in sufficiently tiny regions of spacetime. That's because the Poincaré group, the symmetry group of region of spacetime with the Minkowski metric induced on it, is baked right into the group theory of the Standard Model, and into General Relativity. One can read this as the Standard Model subsuming Einsteinean gravitation into it at that level, and thanks to perturbatively quantized gravity one could equally pencil in a gluon on the particle zoo tables and do gauge theory on that, and expect consistent results outside strong gravity as described above.
Finally, even if other symmetries are added (or the three matter ones are unified) in a Beyond the Standard Model Yang-Mills group theory, the couplings with the graviton outside strong gravity will be straightforward.
So, I don't agree that the fundamental theories of gravity and matter are a patchwork, nor that they mesh poorly, even though we do not have a meshing that works to arbitrarily high energy levels. But crucially, those arbitrarily high energy levels might not even be physically observable; we aren't certain about that yet.
Finally, whatever dark energy and dark matter are, how they generate the metric and how they interact with the rest of the Standard Model are subjects of various research programmes competing with radically different ideas for a theory of quantum gravity.
In response to you, "unlikely" is not the same as "may be".
A couple of times in this discussion, you've argued about the definitions of words, and your definitions have been... at least different from the way the words are normally used. It's kind of distracting from the actual discussion, without adding much.
What, in your usage, is the difference between "unlikely" and "may be"?
(By the way, I'm not arguing against "unlikely" wrt any of these things...)
When you're talking about an extraordinary claim, it's a good idea to use "unlikely" and not "may be". The moon "may be" has deposits of green cheese, we just haven't found them yet. It is unlikely that the moon has deposits of green cheese. It is likely that the EM Drive thrust measurement is measurement error.
These usages convey fairly subtles signals about one's understanding of, and confidence in, a physical phenomenon.
This is typically only learned by people who write papers and have advisors who can guide them.
A really nice example of this which is also immediately readable is Watson and Crick's 1953 DNA structure paper.
http://www.nature.com/nature/dna50/watsoncrick.pdf
It's a classic understated style, with a small amount of boastful brilliance. The passive tone is a bit dated, but you can clearly see little was known about how DNA worked, and they were very careful not to make any strong claims without qualifiers.
The actual mechanism as you'd know bears barely a passing resemblance to that, since you've got the whole DNA replication complex assembly orchestrating it. So yes "suggests a replication mechanism" - but it doesn't remotely work as the suggestion would imply.
The replication complex is just an enzyme, it only speeds up things that are thermodynamically favored (replication can occur spontanteously because the dsDNA is lower energy, but it's rare because forming the phosphodiester bond requires a high activation barrier).
Then why did they go to such extraordinary lengths to find the source of it? Why didn't they just shrug and work around it?
Keep in mind they initially had no knowledge of the theoretical prediction of CMB, which was fairly recent and controversial. They just had a weird observation and busted their butts trying to figure out what it was.
> It was a classic example of being the first measurement of a thing.
Yes, now we know that. At the time it was not clear that it was a phenomenon worth measuring at all. I mean, they thought it was pigeons. It looked like a dumb error at first.
> Excellent discovery, and easy and inexpensive to replicate.
The "emdrive" is also easy and cheap to replicate.
I'm not saying that the emdrive works, I'm saying that experimental results matter. They should not be dismissed just becaus me they seem to violate theory. Violating theory is why people experiment in the first place.
For the emdrive, the effect is so small that it's suggested that the next step is to launch a powerful satellite costing $100mm or more. Uh, really?
From your comment, you seem to be tangled up in results being "dismissed". That's not what's going on, when people make comments about extraordinary claims and extraordinary results. A tiny, hard to measure result is not an OH MY GOD THE THEORY IS WRONG result. It is likely an experimental error.
For the satellite, there is atmosphere drag, magnetic fields, outgassing, etc, all probably bigger effects than the claimed drive effect!
Earth bound labs have much greater control of variables, reproducability, possibility to measure related quantities, possibility to run variations on experiments.
The reasons to do the satellite are (1) PR (2) wanting to NOT disprove the effect.
So? What if there was such a theory? It could still be false or incomplete, like Newtonian physics.
:P
Something that's 1% likely and something that's 75% likely require different amounts of evidence to get to 95%.
It might be an error, in fact it almost certainly will be. But it is not yet certainly an error.
Stand back: science still in progress!
“Whatever Nature has in store for mankind, unpleasant as it may be, men must accept, for ignorance is never better than knowledge.” ― Enrico Fermi
Unfortunately, you have to look into it carefully to find out whether it's experimental error or something more interesting.
And, to return to Everhusk's first post: Experimental error can result in an "anomaly". The experiment is not returning the results we expect. That's an anomaly. An anomaly doesn't have to be new physics.
You have to focus on something - there are only so many grant and R&D dollars to go around
Of course, most apparently whackadoodle ideas really are whackadoodle ideas, but occasionally you get one that isn't, and when that happens, it's usually big. Perhaps a (small) budget randomly assigned to whackadoodle ideas might be a good thing. Like venture capital for science -- most of the theories are going to crater, but once in a while you might get a unicorn.
(The little wet-behind-the ears dears manage to write up six kinds of impossible things just to look at the arithmetic, never mind actual reality. Without batting an eyelid.)
One of them is that of limited funding, there's almost definitely better places to spend money if the goal is progress
Another is how these claims set back scientific literacy of the general public And how it can erode their trust in science Look at how the ftl neutrino debacle did damage, even though no actual claims were made
Chemistry has a concept of a catalyst - Something that lowers the activation energy of a reaction thus increasing reaction rate. Why couldn't nuclear catalysts exist?
A chemical cataylst is a bit different because it doesn't require overcoming the coloumb barrier. If a nuclear catalyst existed, it would have to lower to almost no energy or even bypass the coloumb barrier for a D-D fusion reaction to occur at NTP. Do you know of any situations were the coloumb barrier has been altered?
They are supposedly very energy intensive to be produce, but it proves the concept of lowering the barrier.