Deep breaths. Probably experimental error. Extraordinary claims require extraordinary proof...
God DAMN this is exciting.
God DAMN this is exciting.
As to the whole "we don't actually understand how it works" - we still can't make up our minds as to how wings work, so this isn't overly novel. Sure, we can explain the outcome, but whether it's Navier-Stokes or Bernoulli or something else, we can't make up our minds.
I suspect this will be similar for a long while - although puts physics hat on I think this is likely a relativistic temporal quantisation effect.
> ... we still can't make up our
> minds as to how wings work, ...
I've been convinced that the people who genuinely work with these things and study them properly, actually do know how wings work. You may not, I may not, the mythical "man on the street" may not, but there are people who really, really do.
Another example from Physics - quantum mechanics. We can describe the properties of a QM system, its outcomes based on inputs, the probabilities of states - yet we have not got the blindingest clue as to how it works. We have theories, but again, none are perfect - for instance see the Pilot Wave formulation of QM, which implies a deterministic universe, and isn't wrong, but isn't generally accepted - even though it describes QM systems well, for what little of it has been formulated in the last century.
Is the development of new programming languages evidence that we don't "understand" computers? In some very abstract sense, yes, but in a more practical sense - no.
Saying we can't decide how wings work is not at all in the same category as saying these guys don't know how Q works.
One "not knowing" is about not knowing exactly precisely how to model something perfectly because it has so much complexity.
The other not "not knowing" is about not having even a basic working theory that doesn't use mumbo jumbo and stands up to scrutiny.
By contrast, this "reactionless drive" posits both a completely unknown underlying physical mechanism and a major violation of physics-as-we-know-it (i.e. action without reaction).
We understand QM perfectly well in the only meaningful sense - we can predict the results of any experiment. There's plenty of arguing about "what it means" or "what's really happening", but that's not really physics in my book.
Is argue that understanding the "basement" is very much physics - sure, it can err into the philosophical, but it's still definitely a "real" physical process which drives this.
Once we have a theory of everything, then we can begin trying to form an accurate intuition underlying the model. Until then, there is no point trying to intuit probabilistic models which are designed to predict experimental results, and nothing else.
Imagine if they permeate everything and are generally nonreactive, but still have pressure and viscosity (however small). Maybe the engine is working like an airfoil, displacing the gas locally and using entrainment to create a pressure imbalance with the surrounding virtual particles to cause a larger flow (like in the Bernoulli and Coanda effects). A broken analogy would be the lift to drag ratio of a wing. If it’s 10:1, then you can lift a 1000 pound glider by pushing on the tail with just 100 pounds of thrust.
Maybe a black body is on par with light pressure because the radiation is concentrated like in a rocket, but other geometries are able to interact more strongly with the quantum foam or whatever you want to call it, because they don’t radiate energy in one direction but instead excite the foam enough that it becomes opaque to radiation and can be interacted with (like what happens when an inert gas becomes a plasma). Say the thruster excited the foam so that it was moving faster on one side of the chamber than the other, then that would work like the top and bottom of a wing (where the air on the top side moves faster) and create a pressure differential. The chamber would move to the side with the highest velocity. This might sound far fetched but there’s some evidence that the wave particle duality can be simplified to particles traveling along waves:
https://www.youtube.com/watch?v=fnUBaBdl0Aw
Probably what we’re eventually going to find is that empty space is filled with these virtual particles, weighing much less than say electrons, and because of the uncertainty principle, they are spread over large volumes. So imagine the vertices being shed off of an airliner’s wing. Even though the wing is only a few feet wide, the vortices might be 100 feet wide, so maybe if you could put special glasses on, you’d see a big vortex being shed around the chamber, and if the foam weighs orders of magnitude less than air, the vortex could be really big. It’s probably even possible to tie the size of the vortex to the “lift to drag” ratio of the chamber. Now it doesn’t seem so far fetched that the engine could work when it’s pushing off such a large number of virtual particles.
In fact he said pretty much the opposite to the interviewer asking about magnets in this well known video: https://www.youtube.com/watch?v=MO0r930Sn_8
"Once I asked him to explain to me, so that I can understand it, why spin-1/2 particles obey Fermi-Dirac statistics. Gauging his audience perfectly, he said, "I'll prepare a freshman lecture on it." But a few days later he came to me and said: "You know, I couldn't do it. I couldn't reduce it to the freshman level. That means we really don't understand it." David L. Goodstein, "Richard P. Feynman, Teacher," Physics Today, volume 42, number 2, February 1989, p. 70-75, at p. 75
I have frequently heard the quote without that section, that section seems flawed in that a layman would need to have all the underlying concepts explained to them also, indicating that application of the quote would not scale, as more underlying concepts were necessary to include.
[1] http://en.wikiquote.org/wiki/Talk:Richard_Feynman#Unsourced
[2] http://en.wikiquote.org/wiki/Talk:Richard_Feynman#Teaching_q...
What is it with Hacker News and anti-intellectualism?
http://www.grc.nasa.gov/WWW/K-12/airplane/lift1.html
> There are many explanations for the generation of lift found in encyclopedias, in basic physics textbooks, and on Web sites. Unfortunately, many of the explanations are misleading and incorrect. Theories on the generation of lift have become a source of great controversy and a topic for heated arguments.
There are lots of bits of science where we have "useful lies" used to explain things to people, but when you get more in depth things get trickier.
Clifford Stoll uses the question "Why is the sky blue?" as an example. You keep asking "Why?" as a response and see how far someone goes. Most people will say "light scatters"; some might say "Rayleigh scattering".
Of course, there is a difference between "Science knows but the general population hasn't learnt it" and "science doesn't know" but for a surprising amount of stuff science doesn't know, yet.
A nice blog post on the topic is Sean Carroll's article, "The Laws Underlying The Physics of Everyday Life Are Completely Understood" (http://blogs.discovermagazine.com/cosmicvariance/2010/09/23/...).
Feynman: "Magnets repel each other."
Interviewer: "What I want to know is what's going on ..."
Feynman: "Magnets repel each other."
Interviewer: "...between those two bits of metal."
Feynman: "Magnets repel each other."
Interviewer: "Well then, but what does that mean? Or why are they doing that? Or how are they doing it?"
Feynman: "Ah, [pause] uh you're asking ..."
Interviewer: "I must say that's a perfectly reasonable question to ask"
Feynman: "Of course! It's a perfectly reasonable question."
See also his quote about quantum mechanics - "There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics."
https://en.wikiquote.org/wiki/Talk:Richard_Feynman#.22If_you...
But even something we experience literally every moment of every day, like gravity or magnets, we haven't the foggiest idea of how it actually works. We can describe in great depth anything we wish about our models for these things and experiments can reproduce our theories with exquisite precision.
But these models are merely complex rituals, we don't actually know, at a deep fundamental level, what happens.
The Feynman answer to magnetism, for example, is deeply unsatisfying because he describes all the rituals we've discovered with science about magnetism, but never really answers the question. His answer, in 7.5 minutes are "all the electronics spin in the same direction in iron and that produces a magnified magnetic field large enough we can feel". But why do spinning electrons produce a magnetic field at all? And why does that field work the way it does?
We have built beautiful mathematical tools to describe this force, down to elementary particles, but why it exists at all is a completely mystery.
But what is your point, really?
By "understand" in physics, we really mean that we can predict what will happen in a given experiment to any desired accuracy based on the established "laws of physics".
"But even something we experience literally every moment of every day, like gravity or magnets, we haven't the foggiest idea of how it actually works."
I think this does a deep disservice to how much we actually do know about how the universe works.
Feynman also addresses this, https://www.youtube.com/watch?v=05WS0WN7zMQ
The next Monday, when the fathers were all back at work, we kids were playing in a field. One kid says to me, “See that bird? What kind of bird is that?” I said, “I haven’t the slightest idea what kind of a bird it is.” He says, “It’s a brown-throated thrush. Your father doesn’t teach you anything!” But it was the opposite. He had already taught me: “See that bird?” he says. “It’s a Spencer’s warbler.” (I knew he didn’t know the real name.) “Well, in Italian, it’s a Chutto Lapittida. In Portuguese, it’s a Bom da Peida. In Chinese, it’s a Chung-long-tah, and in Japanese, it’s a Katano Tekeda. You can know the name of that bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird. You’ll only know about humans in different places, and what they call the bird. So let’s look at the bird and see what it’s doing—that’s what counts.” (I learned very early the difference between knowing the name of something and knowing something.)
Models are just a complicated way of calling something, not a way of understanding it. Getting experimental results just means you've used the correct name, not that you understand anything in particular about it.
Calling a hot bright thing "fire" doesn't mean you understand it at all -- no matter how many complex tribal dances you do around an open flame. Knowing what fire actually is gave us modern civilization. For many fundamental everyday things like gravity or magnetism, on the scale from "calling an open flame 'fire'" to "rocket ship", we're charitably somewhere around "learning to cook meat".
No! It just means that we know vast amounts about the Universe, but we still have more to learn.
So I would suggest you to begin by explicitly defining [1] what your particular notion of "understanding" is, so that you can then clarify what exactly is it that you find unsatisfying about modern physical law.
I think Feynman handles the question incorrectly. The question is about his understanding of magnetism, but he places the burden on the receiver of the explanation. If they don't understand the explanation then it doesn't matter. I do get his point in this and I'm not entirely saying it's wrong. But I think also that it's a deflection.
Lets assume a "presently omniscient" listener asking the question, somebody who may not have the knowledge before it is presented to them, but will understand the explanation perfectly as it's provided.
Suppose a Feynman or some other physicist has such a listener and they go on a deep dive into all the myriad and intricate details, the sum of all human knowledge on the matter -- this kind of listener would be able to follow along entirely with every last detail.
This listener would still not have an answer to the question "how do magnets work?" Because science doesn't actually know the answer to this. We have excellent descriptions of what magnets do, and what produces magnetism. We can predict to some nth decimal point of precision the outcome of just about any given experiment such that we don't really bother much with experimental physics about most of the day-to-day magnetism.
But why do those things produce magnetism at all?
The answers to this is basically "it just does". And that's as good as all our knowledge is. That's all we've arrived at. For all we know, every time an electron starts circling something, invisible universe fairies produce "magnetism" magic that does what we observe.
We don't know why magnetism does what it does, only that it does it.
But imagine if we actually understood it, at a fundamental level, if we "groked" magnetism and were the masters of it...
Your final sentence is actually nonsense.
If you assume that time is quantisable (big assumption, I know), and that the planck time is lorenz invariant (not as much of an assumption), then an EM wave at a fixed frequency moving from one reference frame to another could experience quantisation due to the shifting time-base, resulting in an apparent net deceleration - resulting in a measurable acceleration of the system as a whole.
And now I'll take off my fringe hat and get back to the day job.
Accepting a flaw in conservation of momentum is already hard enough without you (and the original paper) imposing a flaw on the relativity principle to explain it.
People used to say that about Newton - until experiment proved that he didn't have the full picture.
It's highly improbable that relativity is any different. Yes, it gives demonstrably correct answers, but that doesn't mean that it holds in all cases.
I mean, why would we be even talking about LQG if we thought relativity gave the full picture?
You're right that I was wrong to say it moved from one reference frame to another, which is clearly bollocks - the EM undergoes an acceleration to relativistic mass, then a deceleration.
Now, you do a huge amount of handwaving to try to explain the results, and in your handwaving you break another basic, unrelated principle. This time, no, I just won't accept your conclusions, you have no reason to break two principles when your experiments support only one.
By the way, the relativity priciple was first stated by Galileo, not Einstein.
Time to trot out my favorite quote about how airplanes fly, from Stick and Rudder by Wolfgang Langewiesche, page 9, published 1944:
»The main fact of all heavier-than-air flight is this: the wing keeps the airplane up by pushing the air down.
It shoves the air down with its bottom surface, and it pulls the air down with its top surface; the latter action is the more important. But the really important thing to understand is that the wing, in whatever fashion, makes the air go down. In exerting a downward force upon the air, the wing receives an upward counterforce--by the same principle, known as Newton's law of action and reaction, which makes a gun recoil as it shoves the bullet out forward; and which makes the nozzle of a fire hose press backward heavily against the fireman as it shoots out a stream of water forward. Air is heavy; sea-level air weights about 2 pounds per cubic yard; thus, as your wings give a downward push to a cubic yard after cubic yard of that heavy stuff, they get upward reactions that are equally hefty.
That's what keeps an airplane up. Newton's law says that, if the wing pushes the air down, the air must push the wing up. It also puts the same thing the other way 'round: if the wing is to hold the airplane up in the fluid, ever-yielding air, it can do so only by pushing the air down. All the fancy physics of Bernoulli's Theorem, all the highbrow math of the circulation theory, all the diagrams showing the airflow on a wing--all that is only an elaboration and more detailed description of just how Newton's law fulfills itself--for instance, the rather interesting but (for the pilot) really quite useless observation that the wing does most of its downwashing work by suction, with its top surface. ...
Thus, if you will forget some of this excessive erudition, a wing becomes much easier to understand; it is in the last analysis nothing but an air deflector. It is an inclined plane, cleverly curved, to be sure, and elaborately streamlined, but still essentially an inclined plane. That's, after all, why that whole fascinating contraption of ours is called an air-plane.«
Now consider a hovercraft. It sits on air. It does not push as much air downward as an airplane of equal weight would push. The amount of air it has to displace is probably proportional to the length of its perimeter (around the sides) multiplied by the height of the cushion of air it sits on multiplied by the air pressure underneath. Double the size of the hovercraft in both horizontal linear dimensions, and you've got double the perimeter, same air pressure (the machine's weight growing proportionally to area) and same cushion height, meaning you're holding four times the weight up with twice the air displacement.
Now consider a low-flying airplane. This is like an inefficient hovercraft, with the ground effect in play. Less air gets "pushed downward" than the same plane flying higher off the ground.
Consider a high-flying airplane. The ground effect is gone, but air's still got viscosity. Fly around the world forever and you'll notice that the amount of air beneath the plane is not actually increasing.
Hovering helicopters have to push more air downward than moving helicopters because they have to fight the stream of downward moving air that they've created for themselves.
If air had virtually no viscosity (suppose atoms were really tiny) then you'd have to fly by somehow forcing air to move downwards. If air had an extremely high amount of viscosity (relative to the mass and power of human-scale mechanical devices) then you wouldn't move it downwards at all -- planes would move around in the air like an amoeba or have a cylindrical conveyor belt surface. Our atmosphere is somewhere between these extremes.
Edit: and of course it doesn't help at all that the silly and trivially disproven equal transit time theory continues to be the go-to explanation for how wings work for so many attempts to teach it.
So when schools teach this kind of BS, you can expect that the confusion will last a long time..
When the magnitude of the observed effect scales roughly with the margin of error of the experiment, one has very good reason to be skeptical ...
this doesn't mean that it sounds too good to be true.
edit: fixed units - dont have easy access to micro, thanks for pointing that out.
(I follow the subject by browsing news now and then at http://talk-polywell.org/ which really is about the small fusion projects. That place should have more details then at Wired.)
Use 'μ' for micro, 'm' is for milli.
You can spell it out, like "91 micronewtons".
You can also use exponential notation like 91e-6 N or 91x10^(-6) N.
To be fancy you can copy-and-paste unicode characters and write 91×10⁻⁶ N.
There's also that nice graph of measurements of the speed of light versus time, in which experiments tended to reproduce the results of (erroneous) previous measurements, due to confirmation bias.
Reproducing an experiment, even with reputable scientists at NASA or reputable universities is in no way a guarantee.