Comment by Nomentatus | Hacker News Reader

Comment by Nomentatus | Hacker News Reader

Parent Full thread

Horsefeathers. To name two examples. The Einstein-Podolsky-Rosen's paper on entanglement “Can Quantum Mechanical Description of Physical Reality Be Considered Complete?” (Einstein et al. 1935) ignored as trash for decades. The Casimir effect was predicted from quantum theoretical calculations, but again, no-one did the experiment for decades because they felt it was a trash prediction that couldn't be true 'cause it ignored basic physical laws that everyone knew had always held and always would. Empty space just couldn't do that. And on and on and on - I've just covered this century a tiny bit, not all the time since Newton. Dark energy anyone?

Knowledge of the mechanisms behind X doesn't always precede discovery of X (why would anyone think it would always do so?) Lack of a known mechanism was why John Newlands version of the periodic table was greeted with contempt, and Mendeleev didn't find it easy sledding at first, either. But the contempt was unjustified. Birds were able to fly before the airfoil was discovered or airflow understood. Electricity was a broad field of study (Maxwell's equations, etc) long before the electron was discovered. The how usually trails the what in the history of science.

I won't be shocked if the Emdrive is a wrong turn, but the idea we could know that in advance is sciencism - the satanic inversion of science - not empirical science.

There is still some place for using theoretical predictions to guide experiments. For example, I have developed a rune that may be used to cast Fireball - it consists of three triangles carved in to a very expensive gold-titanium laminate. If that test fails, I suppose we also ought to try four triangles, a triangle and a circle, the word 'fireball' engraved on the perimeter of a hexagon, three triangles engraved onto a momentum-nonconserving cone...

More seriously, there was a good reason to strongly suspect that the EM drive wouldn't overturn physics: we have probed electromagnetic interactions at energy densities far higher (gamma ray scattering) and far lower (radio telescopes) and everything in-between, and they all seem to be points on a continuous surface defined by Maxwell's equations applied to quantum mechanics. A working EM drive would actually be very close to the magic rune I described above: a wildly noncontinuous point where the laws of physics became massively different for one particular arrangement of matter, and then go right back to normal if you step in any direction around it.

The general use of experiments in science (as opposed to a Homo Erectus experimenting with rock types when making hammers) is to test what we think we know, to see if it's really so. IIRC the "inventor" of the Emdrive had a theory of his own to go by that led him to his device. We probably agree that it's the use of theory to preempt and prevent any experimentation that is pernicious.

(reply to below comment) While not all experiments are equal, there's no right answer, and plenty of room for good and bad luck. The marketplace of ideas ensures enough variety that we don't miss toooo much (maybe.) Yet very often, it's those with the most eccentric and false ideas, such as Keplar, who stumble onto the right path because at least they're looking where nobody else is, for correlations no-one else thought to! So my bias is toward the most novel experiments that are still extremely likely to fail, as I think you agree.

Just this week I was reading up on the Stern-Gerlach Magnet experiment, which discovered spin; something the experimenters absolutely weren't looking for. The idiots (or recipients of blind luck) win a lot of rounds in science, 'cause they're at least trying something genuinely new.

Slightly different alloy = slightly different string theory?

>We probably agree that it's the use of theory to preempt and prevent any experimentation that is pernicious.

So, there's a point about philosophy of science to be made here. If you test one bronze alloy for antigravity, and then test a slightly different bronze alloy for antigravity, and so on, finding all of them to fall when dropped, how can you know when it's reasonable to stop testing bronze alloys for antigravity? Presumably, you should eventually say "this idea has already been tested," and then stop. However there will always be a new ratio of metals to try: the only way to say "this has been tested" or "this hasn't" is to establish enough of a theory to make predictions about the effect of gravity on every bronze alloy, and then trust it when it says it will not become negative (at least, trust it enough to let it rule out potential experiments from grant approval.) When we say, "a new arrangement of photons will still conserve momentum," we are performing exactly the kind of interpolation from other experiments involving photons in cavities that, previously, stopped us from making more and more bronze bars in the search for antigravity.

Sure, but is that line of reasoning similar to the situation with the EMDrive? I thought the interesting part was that there was an actual as-yet unexplained result / measurement. So, going back to the bronze alloys, it's more like "crazy person X has found a bronze alloy that almost seems like antigravity, and it seems to break all fundamental laws of physics". Should we disregard, or humour it look into it? It was always very likely to be some kind of error, but it's a fundamentally less silly exercise.

there was an actual as-yet unexplained result / measurement

  1. "actual" isn't that actual if enough independent 
  scientists aren't duplicating it using scientifically 
  accepted testing procedures.

  2. "actual" isn't that actual when the quantity is down 
  at around noise level.

crazy person X has found a bronze alloy that almost seems like antigravity

You're using words like "almost seems" that just don't match up to the results seen, especially considering the flawed testing methods used.

"Experiments of destroying Mites by several Fumes: of the equivocal Generation of Insects: of feeding a Carp in the Air: of making Insects with Cheese, and Sack: of killing Water-Newts, Toads, and Sloworms with several Salts: of killing Frogs by touching their skin, with Vinegar, Pitch, or Mercury: of a Spiders not being Inchanted by a Circle of Unicorns-horn, or Irish Earth, laid round about it." [Thomas Sprat: from The History of the Royal Society, 1667]

You're misunderstanding my post, so I'll try to put it another way. Suppose I tell you I have proof I created a perpetual motion machine. You'd probably laugh me off as a crank, or at least demand an extremely high level of evidence, to even listen to me.

The EMDrive breaks the known laws of physics as much as any potential perpetual motion machine would, so for it to be correct would imply as much is wrong as our knowledge of physics as the existence of a perpetual motion machine would.

And indeed, you can build a perpetual motion machine out of a reactionless drive.

"any device with a thrust-to-power ratio greater than the photon rocket would be able to operate as a perpetual motion machine" https://arxiv.org/abs/1506.00494

The Casimir effect already produces perpetual motion (in that sense.)

Which raises the specualtive question of whether the Emdrive exploits the Casimir effect to obtain a tiny thrust (in which case a drive subdivided into a vast number of really small trapesoidal sections might produce much more thrust.

There's a simple way to get free energy out of a working em-drive: "at some point, the kinetic energy of the device-driven mass exceeds the energy input, and if this energy is collected via decelerating the mass (via regenerative electromagnetic braking, for example), then there would be a net gain in energy." How do you get a net gain in energy out of the Casimir effect?

Vibration is continuous. Free energy you can get - whether we'll ever harness it to obtain thrust or electric power I don't know - but endless minor amounts of heat, yes.

How do you produce vibration with a force that makes two metal plates stick together? Once they're stuck together, the force goes away. There's no repulsive Casimir effect, and insofar as they bounce, they will quickly come to rest. It's like trying to extract free energy by dropping a ball to the ground.

Let accept that there is Ether, and Ether is like water. In such case, Casimir effect may depend on the flow of Ether, so if plates are in free space and exposed to unbound Ether, then Casimir effect may happen when plates are oriented perpendicular to flow (as usual), and may NOT happen when plates are parallel to flow (my prediction).

The Casimir effect was both predicted by quantum field theory and observed to behave more or less exactly as predicted, so there's very little room for supposed etheric effects. If they were observable, we probably would have seen them just by accident already.

But Ether Wind was disproved by Special Relativity theory, not by Quantum Theory. I see no conflict between Quantum theory and Ether theory. But, if you wish, let accept that there is Quantum Field, ...

The conflict is simple: quantum fields are conservative, which means you can't arrange mass/energy in one way, and then rearrange it another way, and end up with more energy than you started. Gravity is conservative: if you drop a ball, friction aside, it will bounce back into your hand. It can't go higher, and there's no magic you can do by arranging matter to come up with a path where it ends up with more energy than it started with (unless you steal the energy from elsewhere).

Any such effect that exists, would not be called the "Casimir effect" because it would have to obey completely different laws than the actual observed Casimir effect seems to. The Casimir effect is actually evidence against such an effect, insofar as it's perfectly explainable in terms of conservative forces.

I see no word "Ether" in your post. LIGO (which is basically Michelson–Morley experiment at much higher scale and precision) already demonstrated waves in Ether/QF(Quantum Field)/PV(Physical Vacuum)/Space caused by merges of black holes, so I see no point to play this word game anymore.

I'm unsure about why you think that laws of conservation will not hold for Ether, AKA Quantum Field, AKA physical vacuum. If we will be able to get energy from QF, QF will lost that energy and will cool down, so Casimir effect will be smaller until it will vanish. However, there is no shortage of PV in space, and Sun is pretty good at heating it.

However, because of wave-particle duality, and because waves are propagating without moving, and because waves are propagating at speed of light, Casimir effect may be unaffected by rotation even when exposed to raw vacuum for speed less than 50% of speed of light.

You misunderstand the Casimir effect. It's a relativistic analogue of the van der Waals interaction, with a very curious alternative derivation from zero point energies. It is not free/negative energy, it is not free momentum, it was never a controversial subject, we only didn't have the practical means to measure it.

Exploiting the Casimir effect can't give free momentum, because the derivation of the force is rooted in quantum field theory, which like any other physical theory of the last 400 years contains conservation of momentum at its very core.

> The Casimir effect was predicted from quantum theoretical calculations (...)

Thank you. That led me to learning about:

https://en.m.wikipedia.org/wiki/Alcubierre_drive

And:

https://en.m.wikipedia.org/wiki/Krasnikov_tube

Reply on news.ycombinator.com