The quest for a reactionless space drive
boingboing.net
boingboing.net
http://www.otherhand.org/home-page/physics/graduate-studies-...
As time progressed and the experimental apparatus more refined, the “effect” seemed to get smaller, and that’s a REAL bad sign. It was already well below what the theory predicted. That sets off alarm bells. After all this time, if something isn’t in hand to float around a table top, its should still at least be producing unequivocal results.
I am aware of only one positive replication attempt, and even that experimenter (Paul March) had concerns over its validity. All other replication attempts have either been negative or ambiguous. My own experiments were ambiguous.
It seems to make the effect happen, a lot of parameters for the test devices, some not clearly understood, need to be “just so”. The question remains, are the devices being dialed in to create a real effect, or do things need to be just so to cause merely a false positive?
In a world as big as ours, it's reasonable to diversify your investments and keep a few million to one long-shots going, but it's important not to lose sight of the odds. Buy a lotto ticket every now and again, but put the bulk of your money in a 401k or other solid investment.
In this case, I think we're giving this idea more or less exactly the right amount of attention: one dedicated crank (and I use that term lovingly) devoting his life to his crazy theory, and a handful of less invested others occasionally checking in on it. If he can make it work, fantastic, if he can't, well, we didn't waste too much on it.
I love this little anecdote:
I found Hamilton to be extremely bright and knowledgeable, although sometimes I wondered if there was more to him than it appeared. I knew he gave regular briefing sessions at the Pentagon, which seemed strange for an electric car guy. But there was also a time we were speaking on the phone about the possibilities of wormholes and the like. He asked me if I thought it would be possible to create a wormhole with one end being on the surface of the Sun and the other over an enemy on the battle field. I think I was stunned into silence for quite some time, but eventually regained enough composure to say while I had not thought about that before (an understatement!), I supposed it was theoretically possible.
Off topic rant:
Crazy conspiracy people have no idea about how this kind of stuff happens all the time. 99.99% of things never go anywhere, but 0.01% turn into DARPA projects, and 0.01% of those actually turn into better saucepans, and 0.01% of those turn into actual weapons.
1) "Foundations of Physics" is closer to a philosophy journal than a physics journal. It's full of fascinating stuff, but it's far more speculative than any other legitimate journal. When libraries were cutting budgets in the '80's and '90's it was generally the first to go.
2) When highly theoretical phenomena are talked about in engineering terms, the odds of confirmation bias are huge. Who wouldn't want a reactionless-ish thruster?
3) Measuring transient forces of the kind being applied here is extremely hard, and the number of confounding factors is extremely large. The article mentions a mu-metal shield, which will screen some of the Earth's magnetic field from the apparatus but which is useless for screening transient magnetic fields, which get generated by transient electric fields thanks to the magic of Maxwell. Ampere's law tells us CurlB = mu_0epsilon_0dE/dt. So the possibility of residual electro-magnetic forces is non-trivial to say the least, particularly in a room full of conductors and time-varying EM-fields (from the wiring, the pump, etc).
Putting the whole apparatus in a Faraday cage would help, but the history of measuring small (and transient) forces in physics in the past couple of decades (the fifth force mess, Joe Weber's coherent neutrino scattering work) argues that we take these experimental measurements with a large grain of salt, unless they can be shown to be in precise numerical agreement with the theory's predictions over an order of magnitude variation in power input and rate of variation.
The theory may not be wrong, but it needs a lot more experimental investigation and likely theoretical examination as well. Theorists tend not to spend a lot of time critiquing things that look really likely to be wrong, because proving something that everyone thinks is probably wrong, wrong can be incredibly time-consuming and utterly unrewarding. So the lack of theoretical disproof is not very compelling. So far as I know Joe Weber's coherent scattering theory was never dis-proven in publication, either: it was mostly dismissed by informal but compelling arguments at conferences (the best one was simply that there was nothing special about neutrinos in Weber's theory, so if what he said was correct single crystals would coherently scatter x-rays in exactly the same way, which would have shown up as an anomalous low-energy contribution to EM cross-sections that would have been an obvious problem for decades if anyone had observed it.)
That may be true, but you also mention that measuring tiny transient forces is incredibly hard. Thus, the only way to actually get an accurate measurement for this thing is to attempt to scale it up until the force is either unambiguous or the confounding culprit can be found. You've got to try to amplify the signal.
I also don't get the impression that these folks are dummies. I'd be surprised if they haven't done experiments to attempt to rule out electromagnetic effects. Simple ones would involve moving stuff around, doing this in the presence of various magnetic fields imposed by outside sources to see if the underlying effect is still there, etc.
Edit: some more info here:
https://en.wikipedia.org/wiki/Woodward_effect#Test_devices
In particular:
"In 2004, Paul March of Lockheed Martin Space Operations, who started working in this research field as of 1998, presented successful replication of Woodward's previous experiments at STAIF."
There are a few other less conclusive attempts at replication, but only one claimed negative result. But as you say, measuring forces this tiny is hard.
The description on the Great Wiki actually made me more suspicious of the device, not less.
anyone who understands that it's a device for turning bricks into weapons of mass destruction. not that a conventional nuclear reactor isn't one, it's just that it uses more sophisticated bricks.
A reactionless drive, if possible, would still require "effort" to produce thrust in the form of energy. It is not a "free energy" device. The only difference between a reactionless drive and a rocket is that a rocket must carry its own fuel with it, so that it can expel the fuel to generate thrust. The fuel adds additional mass to the whole rocket, so in a way, a rocket requires extra fuel to carry its fuel. Since a reactionless drive does not expel anything, a reactionless drive would not carry any fuel, and therefore could be more efficient by way of lower mass, but it would still need to carry an energy source of some type, such as a nuclear reactor, or a radioisotope thermoelectric generator.
Rockets are certainly capable of accelerating a mass to a significant fraction of the speed of light. However it is important to note that it becomes more difficult to accelerate an object as the object gets closer to the speed of light. You need more energy to add a constant amount of velocity as your current velocity increases. This applies regardless of what kind of method you are using to accelerate - doesn't matter if it's a rocket or a reactionless drive. The difference is only in efficiency - it is thought that a reactionless drive might be more efficient. However if a reactionless drive really is possible, it might provide a lot less thrust than you think.
So even if reactionless drives are developed, they might be more efficient than rockets, but far less timely. I think you'd be waiting quite a while for the reactionless vehicle to attain any sort of appreciable velocity - perhaps decades. As far as weapons go, humans have not met any aliens yet (to my knowledge) and our species currently only resides on planet Earth, so any weapon would be ballistic in nature, to strike targets on Earth's surface. A reactionless drive would be ill-suited for ballistic propulsion because it doesn't give enough thrust. If it was launched from the ground like an ICBM on a suborbital trajectory, it wouldn't be able to escape Earth's gravity, it would just sit on the launch pad. If it was placed into orbit using a rocket as a first stage, and then activated later, it would take a while to deorbit rather gently. The vehicle's velocity would slow down due to air resistance, and its kinetic energy would not be usable as a mass destructive weapon. This is why large explosions are used as weapons of mass destruction, and not kinetic energy alone. Kinetic energy is simply used for timely delivery of the explosive device from a great distance away.
Now, for interstellar warfare, a reactionless drive could be useful if you were extremely angry at another planet in another star system located many light-years away. The large distance between the aggressor and the victim allows the kinetic vehicle a lot of time to accumulate velocity. However the steering of such a kinetic weapon must be very precise in order to hit the target planet, so the vehicle must have the means to estimate its current location/speed/direction, compute the orbits of itself and its target, and apply the necessary course corrections in order to hit that target. It is possible that a reactionless drive might provide vectored thrust, but if it does not, then attitude adjustment thrusters would be needed (either reactionless or conventional.) Accurately steering a vehicle traveling near the speed of light does not seem like an easy task. If the target was missed, the vehicle would be traveling so quickly that it would escape the star system on a hyperbolic escape orbit.
Such a weapon would be quite the undertaking and would be a large energy expenditure for a civilization. It might be more worth it to focus that energy into colonization and defense instead.
Well, yes and no. The speed of a rocket is limited by the specific impulse of its engines. That means that hydrogen-oxygen rockets aren't going to go very fast. Ion thrusters will go a lot faster, but take a long time to get up to speed. If you want to go really fast you need something really exotic like antimatter, but the technical challenges are quite daunting. Theoretically you could use a flashlight, but the batteries would run out before you could get anywhere.
The allure of a reactionless drive is that you aren't limited by the the rocket equation. You may still need a big energy source, but your speed isnt limited by how fast you can spit stuff out your backend.
It's fun reading to look up things like specific impulse, the rocket equation, relativistic rockets, even project Orion.
IANARS.
There's nothing that theoretically prevents a hydrogen-oxygen chemical rocket from approaching the speed of light. But it would need an amount of fuel roughly the size of the Sun to do it with any appreciable payload.
A reactionless drive still needs to carry an energy source, but does not need to carry reaction mass to throw out the back. Hence the term "reactionless."
It does not accelerate at all! It allows you to move, but your net velocity is zero after each move cycle.
So you can shift your position in space, which is useful. But you do not speed up at all.
At this very movement Earth-dust is making its way into space and even leaving our solar system without fuel.
There's a group working on very low mass spacecraft to take advantage of this - http://www.spacecraftresearch.com/MII/MII_overview.html
Well, you actually can't do that. In special relativity when you change of reference frame, the momentum and energy mixes. If you break the momentum conservation in one reference frame, then you break the momentum conservation and the energy conservation in almost all the other reference frames.
If you do the experiment on Earth and in that reference frame the energy is conserved, then the astronauts from the ISS will see that the energy is not conserved, if Elon go to to Mars he will see that the energy is not conserved, even the people on the other side of the Earth will see that the energy is not conserved.
If you put two of these devices in opposite orientations in the opposite sides of a spinning carrousel (and assume that the angular velocity of the carrousel is small enough to ignore it in the calculations) you will see that each of the devices gain some energy and you can harvest it.
So they can't arrange for a capable student to take care of that as part of a work-study program? WTH. Perhaps I'm underestimating the amount of work involved, but it's not like they need to have contributor tiers with silly T-shirts.
You see, he needs more money to try to boost the signal and further test the effect. But since the effect is novel and controversial, attempting to raise such money means he's a con man and invites comparisons to that e-Cat dude from Bologna.
If I were him I would avoid publicity outside the scientific community simply to avoid the character assassination. I'd work with interested other scientists and publish in obscure journals until I could either find the flaw my measurements or generate data so unambiguous that it overcomes the howling.
You are standing in a field looking at the stars. Your arms are resting
freely at your side, and you see that the distant stars are not moving. Now
start spinning. The stars are whirling around you and your arms are pulled
away from your body. Why should your arms be pulled away when the stars are
whirling? Why should they be dangling freely when the stars don't move?
So either it does nothing and stays where it is, or it converts energy into movement at 100% efficiency?
It wouldn't be 100% since some energy would be lost due to internal friction and the need to actively cool the thing to maintain superconductivity (and pump away heat generated by friction). You'd also lose energy in the electronics in generating the oscillating signals, switching, power conversion, etc., and in EMF losses. If it really does work I could imagine it approaching the efficiency of a good motor, just one that creates directional force in a vacuum by pushing against... umm... something. That'd be a question for the theoreticians. :)
You can only shift your location, you can not develop any speed.
So charging the capacitor may make one plate slightly lighter, the other slightly heavier, but its overall mass is the same. Is it this mass change he's trying to use?
It requires no energy or momentum to just change position. Except it's impossible to do in space, but this machine makes it possible (supposedly).
I'm not 100% sure this thing actually is real, I'm just going by the description in the wired magazine, plus reconciling it with the statement that it doesn't violate Newton's laws.
If you're in Austin: http://atxhs.org/wiki/Main_Page
They have presented evidence and a proposed mechanism, have fully published the details of their work, and have invited others to attempt to replicate it or to show where they're wrong. Where's the "pseudo"? It's also important to note that in experimental physics it's more than enough to show an effect that can be replicated. Their currently proposed theoretical explanation could be wrong, but that wouldn't matter.
The article also sets off various other pseudoscience alarm bells, such as the fact that their paper is published in a philosophy journal, and the guy having a history degree instead of a physics degree. But that goes against the naive rebellious spirit of HN that dictates that anybody can overthrow fundamental physics with an experimental setup in his basement, so downvote away!
The article is very much written in the second form, at least as far as I can tell.
"ninety-nine percent convinced" That's not "hmm, that's funny, let's investigate more".
"The theory has been sitting in peer-reviewed literature for more than fifteen years" (a single paper in a philosophy journal...)
"Those who are players in the field of advanced propulsion," he says, "feel obligated, for whatever reason, to dissuade people from considering seriously alternatives to their particular scheme. I think they may genuinely feel they are doing a public service when they say, 'Don't spend money on that, it can't possibly work.'" He gives me a wry smile. "But their own schemes have all failed." Implying that the space industry should invest in it.
She became "ninety-nine percent convinced." She started out skeptical until she investigated it thoroughly.
"Sitting in peer-reviewed literature" only applies to "something obviously wrong with it." He's saying that, if there's a flaw, it must be subtle. That's not saying "therefore it must be right" but merely that there are no obvious flaws.
And for space industry investment, I really don't see the problem here regardless of the context. Imagine, for a moment, that this was a completely legitimate thing that failed to attract any investment. Why would he not say those exact words? If this is something that could be said both by a kook and a legitimate scientist working on a legitimate theory, does that not mean the statement has no deciding power?
It looks to me like this fellow has quite a few peer-reviewed papers out there. Most are indeed in that weird journal, but not quite all.
And I just flat-out disagree with your supposed implication about investing.
Let me be clear: I doubt this effect is real. The difficulty of reproducing the experiment and the fact that the observed effect got smaller as they refined their technique both imply that there's some confounding factor at work. But I don't see any "pseudoscience" here.
"such as the fact that their paper is published in a philosophy journal, and the guy having a history degree instead of a physics degree." -- argument from authority, very unscientific. If an unemployed poodle shaver publishes a replicable experiment, it is science.
"naive rebellious spirit of HN that dictates that anybody can overthrow fundamental physics with an experimental setup in his basement" -- if the experiment works and can be replicated, they certainly can.
There's also a misunderstanding of scientific epistemology in your last statement. Theories are seldom overthrown, but they are often extended. Einstein didn't overthrow Newton -- he provided an extension. Newton's equations still work, but with a very tiny error that only becomes visible at high velocities or with unbelievably precise measurements unavailable in Newton's day. A theory is not an absolute dogma, but a model that is deemed correct within its context -- namely all data and experiments available at a given time. New data or new experiments can extend the context, requiring an extension of theory. If this effect is real, it would not "demolish" or "overthrow" relativity, but would likely require some sort of extension to the theoretical framework. Who knows? Perhaps such a thing could point in the direction of the elusive quantum / relativity synthesis?
I am skeptical (lower-case S) of this, in that I wouldn't really believe it unless the effect could be reliably amplified. So far that hasn't been the case. But I don't consider it at all psuedoscientific to try it out. Even if the effect is a result of something else, doing so will refine your skill at measuring tiny forces and possibly advance the field of experimental technique.
The character assassination and arguments from authority are completely unwarranted, and is a major reason I am not a Skeptic (upper-case S).
P.S. a tangent:
Part of why I think CS advances so fast is that the unambiguous nature of computer "experiments" leaves little room for arguments from authority or character either pro or con. Either something works or it does not. Politics -- that age-old enemy of truth -- are clearly irrelevant.
Except for the fact that he says: "The theory has been sitting in peer-reviewed literature for more than fifteen years, so if there was something obviously wrong with it, the odds are, more than one person would have said that it's not right.". I'm just counting that claim.
> if the experiment works and can be replicated, they certainly can.
And guess what, it wasn't replicated!
> There's also a misunderstanding of scientific epistemology in your last statement.
I understand that, but conservation of momentum is one of the most fundamental facts of physics, maybe even THE most fundamental fact of physics, certainly as fundamental as conservation of energy (in relativity it's basically the same thing -- both are components of the energy-momentum 4 vector). It holds in Newtonian mechanics, general relativity, and in quantum mechanics. It is at the very basis of those theories. Finding something that contradicts that would completely destroy that foundation. It would be the single biggest discovery in the history of science. To present that with such confidence as the article does is just ludicrous. If the article was about creating energy from nothing, should that be taken seriously too, with similarly weak evidence?
Yeah, it'd be pretty huge, but it wouldn't "overturn" anything. All the science we've done to date remains quite valid.
Our current theories all state that momentum is conserved. That's because all our current experimental data shows that momentum is conserved.
Now let's say we had a new experiment that showed what appeared to be a violation of conservation of momentum?
This would mean we'd need a new theory explaining how this experiment worked. But this new theory would also have to explain all our previous experimental results -- in precisely the same way that Einsteinian mechanics encompasses, explains, and agrees with all of Newton's results. In other words you'd have to answer the question of "if momentum isn't always conserved, why does it almost always look like it's conserved?"
There's another possibility too. What if this thing works and momentum is still being conserved? What if it's pushing against something, such as some kind of dark matter field, WIMPs (weakly interacting massive particles), neutrinos, virtual particles, ...??? I'd start by asking questions like that before I'd toss conservation of momentum. Even the hardest vacuum is full of particles ejected from stars and other things flying all over the place and even "popping into and out of existence" (in quotes because that's only an analogy) as shown by things like the Casimir effect. What if it's a "WIMP thruster" or something weird like that? An interesting experiment would be to send one flying on a one way trip to nowhere out of the solar system and see if it works as well in interstellar space as near the sun. The sun's throwing out a lot of particles, could it be pushing against those? Has he ever tried running it at night (far side of Earth) vs. during the day (sunward side of Earth)?
Of course it'd still be really useful as a space drive if it could be scaled up, regardless of the mechanism.
I'd build two and have them push against or toward each other. Must be something funky in there.
I wonder if the thing, or a part of the thing, changes thermal energy more/faster than it changes kinetic energy? That would be an interesting conservation solution. If it would be energetically cheaper to just heat something up that has differential IR emission on each side...
That's what they are claiming: gravitational waves travel back in time, and move all the other matter in the universe a little bit so that momentum is conserved. Or something.
My reading is that this thing, assuming it worked, would have the same problem as ion drives in that it would require a massive power plant. It solves about 1/3 the technical problem of a star drive: where to get the mass. But about 2/3 of the problem of star travel is where to get the energy. High-power-density fusion and antimatter-matter annihilation are the only sources I know of that make star travel thinkable on anything like a human time scale.
Which, funnily, leads back to a point others and I were making in a different subthread[0] - that any device that allows interplanetary travel in timespans reasonable for humans is at the same time a weapon of mass destruction.
Humanity needs to get its act together if we're ever to get out of this rock :).
We already have plenty of weapons of mass destruction -- sufficient to eradicate modern civilization if not human life entirely -- so its hardly as if not developing technologies necessary for interplanetary travel protects us from such weapons.
That's a good indication that the effect isn't real. But it has nothing to do with whether this thing is "pseudoscience." Proper science produces negative results all the time.
"-- argument from authority, very unscientific. If an unemployed poodle shaver publishes a replicable experiment, it is science."
Not only is it an unscientific argument, it's just wrong. The guy did his undergraduate and masters in physics, then switched to history of science for his doctorate because he realized that nobody was going to fund what he wanted to work on and he needed a job. He also works with other physicists who do have doctorates in physics.
That's very logical -- it's incredibly hard to fund anything speculative.
My underlying point is that being honestly wrong doesn't make you a pseudoscientist, and should not result in character assassination or claims of being a fraud or a quack. That sort of thing contributes to a climate of dogmatism and extreme risk aversion in science that more or less guarantees that nothing new will ever be discovered.
The data can't 'go against' general relativity because it's agreed by everyone--the researcher included--that he hasn't got all the variables controlled, and so the data doesn't 'go' at all.
It'd be pseudoscience if he was cherry-picking data that shows his theory to be correct, or ignoring existing data that conclusively shows that his theory is incorrect. He doesn't seem to be doing the former; I don't really have a way of telling if he's doing the latter.