Its waiting on room temp superconductors I believe. Otherwise you have to cool a 1000km of cable and of course the material needs to be reasonable ductable. And dont hold your breath on room temperature superconductors, it may not even be possible...
I like the epilogue. I too wish I could go back to my younger self and describe this understanding. I would try to explain to myself that each pattern can be seen as an object in and of itself. That an algorithm is a way to move between these objects in a specific way that marries with a particular human goal. I would try to explain that each step of an algorithmic process combined can be seen independently of time as a pattern in and of itself and as such is itself an object. A process is a noun, a thing just as much as a chair or a lightbulb. I would say that in order to find an algorithm to solve a goal, all one needs to do is imagine the shape formed by this goal and construct that shape from the shapes that are readily available to you. Be them finger movements on an abacus or bitwise operations in a computer memory. And then I would explain that the universe can be seen in this way. The entire thing as a single object out there in phase space. I would tell myself that I suspected that all possible shapes exist, that the shape of your life exists only as much as the shape of a thing that you imagine while dreaming. This was the understanding I have been searching for since my early teens. It is such a joy to have found it, I like to think my younger self would have cherished it as much. But I may have discarded them as the ramnlings of an old fool.
Don't you think thinkers have always thought this at every point of time in history? The answer is yes they have. There have been large innaccuracies discovered in our models before. So what makes you think that it's so different this century? I'm not saying the these drives work, just that appearing to fundamentally violate our models makes it unlikely to be a real effect. But it isn't impossible, lets not be too self assured here. Pride makes you feel good, and bringing emotion into your reasoning is rarely a good thing where science is concerned.
I get really tired of these ignorant psuedo sceptic responses. It's so obviously a straw man attack it makes me cringe. Why are you so set on assuming that it is violating conservation of momentum? No one of import is claiming this. My god, authority must always be right! All who move beyond appeals to authority when constructing arguments must be decried as beyond the fringe! Heathens! Infidels! Traitors! Expell them from within the walls of science, from the walls of Freedom. Yeah muh Science/freedom/nationalism/whatever makes me feel safe by allowing me to feel like I belong and satisfies a psychological need to construct a them and us world. Ffs. Grow up. Seriously hacker news. Grow up. Please, please humanity, grow up. Arrrrgggghhhh. I cant even. - Edited to remove swear words
I honestly don't even know where to begin in responding to this. You've called me (or my words) "ignorant" and "pseudo-skeptic", you've suggested that I have relied on appeal to authority in making my arguments, and you've implied that I'm motivated by an ignorant "us vs. them" mentality. You've told me to "grow up". All of that seems like pure personal attack, rather than any sort of robust engagement with ideas.
The only actual point of science that I can find here is your claim that "No one of import is claiming" that these drives violate conservation of momentum. In my original comment, I explicitly addressed this: the EmDrive FAQ's own attempt to explain how their drive doesn't violate momentum conservation seems to imply a violation of momentum conservation. Maybe I'm mistaken about that somehow: if so, I'd very much appreciate knowing how! (At the very least, I find it perhaps telling that the site's authors don't understand that their attempted answer is no answer at all.)
As for the personal attacks, I'll just give one piece of context for the "ignorant" bit. I'm a tenured professor with a Ph.D. in theoretical high energy physics from the University of Chicago. That doesn't give me any special magical authority to declare truth about the universe, but it does mean that I've got a pretty solid base of knowledge for my statements and (I hope) decent judgement about how confident to be in my beliefs about questions in my area of expertise. I work on crazy theories that might or might not wind up describing our world at all, so I'm very aware of both the vastness of our ignorance and the importance of pushing at its boundaries in bold and unconventional ways. And with all that background, I think these drive ideas sound entirely unreasonable. If you've got equally solid reasons to believe otherwise, more power to you, and I'd love to hear them.
I was angry at a great deal of posts like yours over a range of topics. Perhaps in this instance the anger was missplaced. In a previous post I have worked out how to articulate my concerns: A lot of the time posts with an overtly negative tone that claim to come from a place of rationality, are in fact reactionary. They claim to be defending a core of rationality from encroaching confusion, when in fact they are a symptom of irrationality, a result of the innapropriate application of emotional reasoning to areas of life where it has no explicative power. I believe that the rigidity of the models to be found within the minds of certain kinds of folks has less to do with the defense of rationality and more to do with the defense of identity. I find it extremely irritating to deal with people who are irrationally certain in an uncertain world - especially when they justify themselves by claiming they are just being more reasoned than the next man. Having said that I can hardly claim my post was anything but an emotional outburst.
I got the same response when I informed /r/science that "No, no one in the OPERA Experiment actually believes that neutrinos are actually going faster than light and breaking special relativity, they're asking for input on what went wrong with their observations"
I got a tirade of responses just like yours informing me that I'm a biggot, childish, close minded, backwards thinking, co-dependent on authority, cretin who will be the responsible for the downfall of humanity. ect. ect. ect.
I believe I got down to -45 karma on that post, my lowest score ever, and I wasn't being aggressive or hauty or anything. I was just saying "they're just looking for explanations on their observations, there's no way it's actually happening."
I never got an apology for that, strangely enough.
> Why are you so set on assuming that it is violating conservation of momentum?
Because the EmDrive experimenters themselves are saying that thrust is being produced without any exhaust--i.e., momentum is being added to the cavity in one direction, without any compensating momentum being ejected in the other direction. That violates conservation of momentum.
> No one of import is claiming this.
Not directly, perhaps, but that is the clear implication of the results they are claiming. No exhaust, no momentum conservation. If they were saying "oh, we did see some radiation being ejected in the other direction", that would make a huge difference. But they're not.
> All who move beyond appeals to authority when constructing arguments must be decried as beyond the fringe!
It's you who are appealing to authority: you are saying there can't be violation of conservation of momentum, simply because the experimenters said there wasn't any. That's not how science works. You're supposed to question what they're saying; you're supposed to look at logical implications to see if what they're saying is all consistent. You're not supposed to just take them at their word.
'You're supposed to question what they're saying; you're supposed to look at logical implications to see if what they're saying is all consistent.' What you are doing here is saying - I will take my model of the world and check that their observations are consistent with what it predicts are physically possible. Then saying I found their observations to be inconsistent with how I expect the world to behave given my model. A natural follow on step from this is to conclude that they have missunderstood how their experiment is constructed - there is something about the way they are performing their experiment which is not accurately reflected in the model of their experiment. For instance there might in fact be conventional exhaust escaping from the device in a manner they had not anticipated. This is fine, this is also my interpretation. But where we differ is that I am very able to imagine a world where my model is innacurate and I appreciate that sometimes things that appear to require radically different models can in fact be produced by relatively minor ammendments. And that many people I meet seem to be very unwilling to question their own models and ammend them where necessary, upsets me. It upsets me because I believe in many instances it is born of the same kinds of irrationality that the whole enterprise of rational thought was designed to fix in the first place. At times, to me, it feels like it has become just another church for people to cling to. The rigid models I percieve within public discourse on these topics are a symptom of the very same creeping irrationality that they are purportedly defending against.
> What you are doing here is saying - I will take my model of the world and check that their observations are consistent with what it predicts are physically possible.
Conservation of momentum has been confirmed by many, many experiments; it's not just a feature of my or anyone's "model" of the world.
> there might in fact be conventional exhaust escaping from the device in a manner they had not anticipated.
Yes, that's quite possible. But as far as I can tell, the experimenters are not even considering that possibility, or checking for it.
> I am very able to imagine a world where my model is innacurate
Sure, imagining a world in which momentum is not conserved is easy. But, as I said above, experiments have shown us that we do not live in such a world.
Of course it is logically possible that momentum is conserved almost all the time, instead of absolutely all the time, and these experiments just happened to be the first ones anyone ever ran that poked reality in a place where momentum was not quite conserved. But in Bayesian terms, my prior for that being the case is much, much lower than my prior for the experimenters having made a mistake somewhere. Experimenters make mistakes all the time; but nobody has yet discovered any violation of a conservation law.
'it's not just a feature of my or anyone's "model" of the world.'
This may just be semantics, but I dont see how you could argue that it isnt a feature of a model of the world. A neural representation of the world shared amongst a group of humans. Tested against reality in the best ways we can imagine. But it is still just a model, it is not actual reality. Are you really so sure about those priors? You are also have a very influential prior there which supposes that that if the device functions, it does so because it violates conservation of momentum. Surely you cant know this? Are there really no other explanations which fit more neatly with our current models?
> it is still just a model, it is not actual reality.
We have a model that includes conservation of momentum. But experiments have shown that reality also includes conservation of momentum--that that feature of the model is an accurate representation of reality.
> Are you really so sure about those priors?
Yes.
> You are also have a very influential prior there which supposes that that if the device functions, it does so because it violates conservation of momentum.
That isn't a prior; it's a hypothesis--the one the EmDrive proponents are claiming.
> Are there really no other explanations which fit more neatly with our current models?
"The experimenters have made a mistake somewhere" is another explanation which fits in more neatly with our current models. Their mistake could be that the device isn't actually producing thrust, or it could be that it's producing thrust because it's ejecting radiation out the back end which they aren't detecting. Either one of those invalidates the EmDrive proponents' claims.
Oh no no. Thats not how it works at all. People only look in places where they expect to find things. Thats why we dont rub sticks together all day when building a nuclear reactor. Its also why it can take centuries to correct mistaken scientific conclusions. While I fully expect homeopathy to be bunk, if it is not then I would not be surprised that it has not been scientifically verified. Market forces/darwian selection/distributed search algorithms that we tend to find in the real world are not finding global minimums, only local minimum. This makes it tricky to construct arguments of the form, well if we havent found a solution of form x then x must be impossible within frame y.
That's not entirely fair. D wave is attempting to use quantum effects anneal to solutions faster than a classical computer would. It's not what we would usually think of as a quantum computer, but its in the right ball park. No?
Well my desktop also uses quantum effects. So did valve computers at the time, thus, I don't think anybody ever built a "classical computer".
Yes, that's the definition they use on their site. No, I don't think applying it verbatim to my computer is unfair.
Ok, they created a different kind of classical computer. One that may be able to solve some kinds of problems better, like a specialized computer often does. Yes, it could have been huge (but wasn't - too bad). But it's not a quantum computer, and their marketing is dishonest.
They claim to make use of quantum effects -- in an abstract sense, quantum tunnelling across potential peaks in the solution space to access classically unreachable absolute minima. If that claim is true, then I agree that D-Wave is a type of quantum computer. What is disputed, I believe, is the truth of the claim.
Im slightly concerned about having ~5w of beam formed ultrasound tracking my mobile phone as I clamp it against my ear to make a phone call. I will need convincing!
The really dangerous part is you can't tell until it starts damaging your hearing, and sometimes not even then, depending on decibels.
You won't hear the sound, so you're depending on it meeting your pain threshold to be warned that something is happening. If it's "merely" 100db or so (a loud drill), you won't feel a thing, and could be exposed for hours without noticing.
These are the lasers of hearing. Without really good studies to back up the safety of this amount of energy, I might just end up avoiding all starbucks.
Depends on the frequency, if it's something like 30kHz I would worry, but for MHz range I think it's pretty harmless (in the "loud sound" item, which doesn't mean these are all the issues that might arise)
I saw it in london once. I failed the test so badly that the interviewer refused to believe that I had written the demo project which got me a first interview. He said it was one of the best he had ever seen. But then said I couldn't have written it because I was failing the interview so badly. People who dont get that nervous just dont understand how debilitating being really nervous is. Also the white board code challenge was a total waste of time.
