Uncertain Propulsion Breakthroughs?
centauri-dreams.org
centauri-dreams.org
I do think people miss one small aspect of this story. How long has it been since we've had a device built that we've no understanding of the principles of it's operation? I think that's an amazing fluke and (if the effect is genuine) something worth celebrating (just because it's so rare).
For example: for 30 years we had research blasting cholesterol and saturated fats as evil, because predecessors had that result, some arguments were completely circular (saturated fats are bad because they raise blood cholesterol, and blood cholesterol is bad because a bad thing raises it... with no research trying to find how much any of the two really affect health).
Another example is thyroid diagnosis, after discovery of TSH test, medics started to use it exclusively, and accuse patients with normal results but with severe and advanced symptoms of having psychological issues, also many thyroid doctors never bother in ever asking for other relevant tests, like t3 and antibodies, and the TSH tests frequently use outright dated target ranges, with medics skeptical of new research because the old way is mostly working in their experience (since by their definition, people with symptoms but normal values aren't sick, thus their treatment is 100% effective, since it helps all sick people, and the "non-sick" are delusional and thus it is failure of other medical fields that they are sick)
Other example is any medic that saw patients improve under certain treatment, and then start to always use that treatment in a cargo cult manner, without paying attention to any research that proves that it is misguided, like all those kids forced to take ADHD medicine in their early life.
November 2016 Sugar Industry and Coronary Heart Disease Research A Historical Analysis of Internal Industry Documents Cristin E. Kearns, DDS, MBA1,2; Laura A. Schmidt, PhD, MSW, MPH1,3,4; Stanton A. Glantz, PhD JAMA Intern Med. 2016;176(11):1680-1685. doi:10.1001/jamainternmed.2016.5394
The SRF sponsored its first CHD research project in 1965, a literature review published in the New England Journal of Medicine, which singled out fat and cholesterol as the dietary causes of CHD and downplayed evidence that sucrose consumption was also a risk factor. The SRF set the review’s objective, contributed articles for inclusion, and received drafts. The SRF’s funding and role was not disclosed. Together with other recent analyses of sugar industry documents, our findings suggest the industry sponsored a research program in the 1960s and 1970s that successfully cast doubt about the hazards of sucrose while promoting fat as the dietary culprit in CHD.
http://jamanetwork.com/journals/jamainternalmedicine/article...
(PS - I've known a Shaman or two, and they were quite sensible people, for the most part, except when they started mixing in miscellaneous white people's trashy magic.)
In this case, all the em-drive test only give a very weak force that is very difficult to measure and may be caused by other causes (probably thermal because the device gets hot or something equivalent to an electromagnet because it use a current).
"To date, the mechanism of action of paracetamol is not completely understood."
and:
"It is the most commonly used medication for pain and fever in both the United States and Europe."
"Not completely understood" is not the same as "we have no idea why it works", but still I find it telling for such a popular product.
edit: link
http://www.npr.org/templates/story/story.php?storyId=9700789...
[1] https://www.sciencedaily.com/releases/2006/03/060325232140.h...
> Thin superconducting films are predicted to be highly reflective mirrors for gravitational waves at microwave frequencies. The quantum mechanical non-localizability of the negatively charged Cooper pairs, which is protected from the localizing effect of decoherence by an energy gap, causes the pairs to undergo non-picturable, non-geodesic motion in the presence of a gravitational wave.
The issue is that distorting gravity has far more consequential effects due to generally relativity than just moving something. You are actually distorting time too.
That explains the significance of the floating hole-puncher confetti in the movie Primer.
"Proud to say that we have a partnership now - so the launch is already funded, and we hope to get a launch slot in 2017."
If this works by impelling against the Earth's magnetic field, provided it is more efficient than a simple magnet, it could still have a market with satellite manufacturers.
[1] https://en.wikipedia.org/wiki/Orbital_decay
[2] http://space.stackexchange.com/questions/9087/how-often-does...
To get a clear result we need something out closer to geostationary, flying for months well away from the earth's irregularities.
A recent paper [1] quotes this system's predicted efficiency at 1.2 mN/kW. Hall thrusters, a propellant-throwing electric engine, perform at 60 mN/kW. Non-propellant systems like light sails, laser propulsion and photon rockets perform around 0.0033 to 0.0067 mN/kW.
If this works, and that's a big if, a 50x performance improvement over the prototype is not unrealistic.
That's a completely different premise than the em-drive has, though. It's supposed to not depend on an external field; developing a force between two magnets wouldn't exactly qualify as (non-)rocket science today.
The people have been doing experiments on the EM drive and have been getting unexpected results.
Nobody really knows why yet, but that's kinda the point.
Is thermodynamics flawed? Is it pushing off of "dark matter"? Is it a completely new and novel scientific effect?
Any of these circumstances would be interesting.
That doesn't look like people trying to sell things to me. That looks like a lot of different people from different backgrounds playing around with an experimental setup that does something unexpected.
The only difference I see is that with the FTL neutrinos, folks were saying this breaks a mathematical model that we've proven over and over again. With the emdrive, folks are saying If this works, it's by some model we do not yet understand. It doesn't attempt to disqualify an existing model; it suggests there's some other model applicable that we don't quite understand yet.
For most folks, this is quite more upsetting than the FTL guys. I get that. Still, observe first, theorize second. I'm sure the theory folks will catch up, and it'll probably be some sort of EM leakage we're talking about. But maybe not. Maybe we've accidentally come up with a new kind of photon rocket. That's what makes the story fun.
It would very much disqualify conservation of momentum, which is another way of saying that the laws of motion are the same here and one meter down the road.
Conservation of momentum has been observed in countless experiments for centuries, in a broad range of conditions. It was indeed observed first; there's no catching up needed for the theory. It's always valuable, and in a sense exciting too, to test it again beyond the range where it's already been tested, even if you expect a negative result (the null hypothesis holding). But that's not what's happening:
If your goal is to learn, and you see momentum not being conserved in your prototype space engine, you start dismantling it, simplifying it, until you stop seeing it. And then go back one step to see it again. Your device might not be a space engine anymore! But now it's simplified; easier to reproduce, and easier to model and analyze. The laws of nature don't care about the purpose and coolness of your device, they apply the same. You also take your measurement apparatus and calibrate it against something unrelated, in many conditions, to make sure it's not lying.
You might have a different goal than learning: to achieve cheap space travel, which is a great thing. If then you build a prototype space engine with the hope that it won't conserve momentum, and you see a positive result, there's already the first red flag. If when you see that, what you do is trying to explain it with new (or with wrong) theory instead of questioning it, there's the second red flag. Healthy debates, and playing with technology in a lab, are good things. But not all good things are science. Our minds are too easy to fool, and people are doing this without condoms.
A summary of the parent article is "The experimenters did not do the obvious control experiments [e.g. testing under a null load], thus there are currently no results at all."
Yes you heard that right: guys who misunderstand physics go and design a reactionless thruster which, when measured in their shoddy experimental setup, produces a measurable thrust.
If there really is a measurable thrust, then the Laws of Motion are wrong and General Relativity is wrong. I'm disinclined to believe that long-held principles of physics will be upended by some guys who designed something based on a misunderstanding.
Pons and Fleischmann were straightforward in their error. This is bozo territory.
Outright dismissing new ideas, no matter how far-fetched, is very much the antithesis of the scientific principle. You mustn't forget that everything we take as indisputable fact today, was an outrageous far-fetched theory at some stage.
It was barely yesterday that Barry Marshall was ridiculed for proposing that stomach ulcers are bacterial, because everyone 'knew' that bacteria can't survive in such an environment.
Unfortunately it seems likely we won't learn much by finding the possible sources of error - the sources are already well understood by people doing low force experiments.
There's a hell of an experimental body that led to (and supports) our current laws of motion. These laws aren't "just theory", and they definitely aren't dogma. Are these experiments probing the laws in a region they haven't been tested before? Can these unexpected results be reproduced outside of the framework of a cool engine for space travel?
E.g. there's a difference between measuring for the first time the spectrum of antihydrogen, which we predicted with the strongest confidence would be the same as hydrogen's; and measuring the spectrum of hydrogen with Rock&Roll sounding within, because "we can't know if any specific music genre will have an effect until we test it".
So yeah, if people want to spend their own resources testing this, the more power to them. But the way it's been done makes it look like they're more interested in a cool positive result than in unveiling the truth, and that mindset leads to things like the N-rays.
This is wrong. There is a strong selection bias, where a many team tried this and only those that got a "successful" measurement get press.
It's very difficult to get the list of all the unsuccessful (unpublished) experiments, but someone recollected a list em-drive test http://emdrive.wiki/Experimental_Results The important column is the last one. More than 1 means that if it's correct the device is breaking the current laws of physics. Anyway, I count 5 zeros in that list. [And I think that the other are experimental errors.]
It's a subtle distinction, but an incredibly important one. But that same subtlety can sometimes be lost when it's discussed by the general public. The policy debate over climate change is an excellent example. Speaking strictly in terms of the often quoted statement that "97 percent or more of actively publishing climate scientists agree," [0][1] it's clear how different individuals can read very different meanings into that statement. For the scientists themselves, while the statement is referring to scientists as individuals, it's based on the published research that informed their views. Amongst the general public, particularly those who don't accept anthropogenic climate change, the statement is understood as referring to the beliefs of the individuals. It's taken as an appeal to authority (and it doesn't help that many politicians and activists who want to take action often use it as such). The same statement is understood in two very different ways based on the reader's background and understanding of what the scientific method actually is.
Returning to the subject of the em-drive, the reason for skepticism is precisely because it flies in the face of our basic understanding of the physical world. The more well-founded a theory is, the greater the burden on any new findings that would seem to contradict it. That's as it should be. But if those new findings hold up under scrutiny and are verified, even a basic, fundamental law can and will be revised. That's how the scientific method works.
Personally, I'd love for the em-drive to be proven if only because it would represent such a fascinating shift in physics. To say nothing of potential applications. But I'm inherently skeptical. Not because of a dogmatic acceptance of the laws of motion, but because those laws are already so well-supported.
0. http://climate.nasa.gov/scientific-consensus/ 1. http://iopscience.iop.org/article/10.1088/1748-9326/11/4/048...
[1] https://en.wikipedia.org/wiki/Physical_theories_modified_by_...
With enough proof you can convince the physics community, even if the result is initially weird. My favorite examples are https://en.wikipedia.org/wiki/Wu_experiment and https://en.wikipedia.org/wiki/High-temperature_superconducti... .
I think you can push a little against the magnetic field to rotate and change your orientation, but to gain height the magnetic field is not useful.
[Edit: Mmmm I'd change "but to gain height the magnetic field is not useful." to "but to gain height pushing against the magnetic field is not efficient."]
Another way it might work is by freeing atoms from the backplate of the resonant cavity, like an ion thruster. I hope they include a method of measuring the degradation of the backplate.
I suspect it just won't work, though.
> First, I cannot stress enough that there is no new EmDrive “effect” yet about which to theorize. The physical evidence on the EmDrive is neither defensible nor does it include enough operating parameters to characterize a new effect. The data is not even reliable enough to deduce the force-per-power relationship, let alone any other important correlations.
> Do you want to know our conclusions without any regard to how we reached those conclusions? ... If you answered “yes” to any of those questions, then you, like me, have natural human cognitive dysfunctions.
What else can I do?
That sounds to me like a "regard to how they reached those conclusions" (maybe a regard to how they reached a subset of their conclusions, and extrapolating to the rest). It's not the most regard you could possibly have, but it's lots.
> ...take the time to notice both the pros and cons of the article, not just the parts you want to be true. Deciphering reality takes time instead of just listening to reflexive beliefs. It requires that one’s mind be open to the possibility you might be right and equally open to the possibility you might be wrong.
Very frustrating.
Tube filaments are quite different than lamp filaments - tubes need a material where electrons are easily emitted from the surface. Tungsten is good for lamps but terrible for tubes. A little thorium oxide or barium oxide helps a lot. But there was no theory to indicate in what direction to go, and it took 30 years before trial and error produced results.
Its mainly the need to carefully characterize and document all the test equipment and EM Drive support equipment to make sure its not caused by the test setup. This would involve testing with a dummy load so things like interactions with chamber wall can be ruled out or if there are, the effect can be mitigated or accounted for.
Basically they proved their test setup produces thrust, but haven't proven the thrust was a direct result of the EM Drive. They need to more rigor to prove its only the EM Drive and not a setup error (eg: something like the FTL neutrinos turning out to be a poorly tightened connector).
I had always wondered about something there, though it isn't related to the EM Drive. The original pages posted a few numbers claiming that even with a Fusion rocket-based propulsion system, interstellar travel was still wildly impractical, like thousands of supertankers of propellant to send a Space Shuttle-sized capsule past the nearest star system in 900 years without stopping. Yet many Sci-Fi and semi-scientific sources make it seem as if nuclear rockets are a viable interstellar propulsion. I always wonder who's right, and if I can find some more detailed numbers to back it up either way. Thought about it enough that I might actually try and calculate it myself one of these days.
*more properly said "beating to windward" https://en.wikipedia.org/wiki/Tacking_(sailing)
After all, they've made the same claim repeatedly for 15 years after their first experiments were demonstrably not what they claimed.
Let the experiments decide what is right or wrong.
Low earth orbit isn't perfect either. You still have micro gravity. And the experiment requires a lot of power, and very sensitive instruments to measure the phenomenon. How do you get sensitive instruments which are expected to be operating near their error threshold into orbit without damaging them?
Orbital experiments will have to be smaller, and use less power, so the effects will even be smaller. But the instruments will have to be tough enough to withstand 5G. And the apparatus could still be introducing other errors, like coolant momentum, which also isn't magically eliminated by being in space.
You put the engine in space, with solar panels, and you see if it stays there or falls back to earth.
There is no experimental error, or even measurement devices.
It is a space engine. Either it flys or it doesn't.
Over the course of a year, it will be obvious if it works or not. Because if it doesn't work it will fall to earth.
Not just repeatable, but in different physical configurations of the drive test bed. Right now the tests are using a rotating base that has little to no calibration, much less the hardware, if I understood the link correctly.
We have a thing, it's owner claims it works by either Method_A or Method_B, science is about taking the thing, testing the crap out of it, and being able to say at the end of all if it, "actually it turns out it works by Method_C"
It seems you have some wires crossed somewhere. Science and Rational behaviour are unrelated, they are quite well correlated but as separate concepts they are not causally linked. Historically connected obviously, but not causally linked.
Extraordinary claims require extraordinary evidence, which is why every good scientist expects this effect to go away (regardless of hope as to whether it is a real effect or not).
"...we must begin a more in-depth experimental program using qualified and impartial labs, plus qualified and impartial analysts."
Maybe humans don't really belong in labs in the same way that they don't belong in factories.
It's amazing people are still giving this bollocks the time of day.