With WISE now on its way (a spectacular launch in the dark at Vandeberg Air Force Base), we now turn to the realm of exotica. Specifically, can we find ways to exploit the quantum vacuum to produce propulsion? I’ve seldom had such a flurry of interested emails than what followed the appearance of a paper by Alex Feigel, recently put up on the arXiv server. Feigel (Soreq Nuclear Research Center, Israel) discusses modifying the momentum of the quantum vacuum, an idea dear to that segment of the interstellar propulsion community that focuses on ‘propellantless’ propulsion.
Some background: Heisenberg’s uncertainty principle implies that it is impossible to achieve an absolute zero electromagnetic energy state in the vacuum of space. The measurement of the Casimir effect in 1997 demonstrated that a force would be exerted between two narrowly separated conducting plates. Indeed, at the micron scale, such plates are squeezed together as longer wavelength waves are excluded. The possibility of creating net propulsive forces using this energy was studied by NASA’s Breakthrough Propulsion Physics program during its all too brief lifetime at the agency.
A vacuum, then, is not free of energy, but seethes with electromagnetic waves coming into existence and popping back out of it again. We know these are measurable forces but what interests Feigel is the momentum associated with these electromagnetic fields. Learning how to manipulate that momentum could allow us to create a reaction we can use for propulsion. From the paper:
In this article we demonstrate that aggregating or rotating magneto-electric particles change[s] the momentum of [the] quantum vacuum and, as a consequence they acquire the resulting difference. It follows from momentum conservation: any change in momentum of zero fluctuations is compensated by a corresponding change in the momentum of a material object or electromagnetic field. These new occurrences of the vacuum momentum transfer do not require external means, such as previously proposed modification of the magneto-electric constant by applying external electric and magnetic fields or suppressing the quantum vacuum modes by cavity-imposed boundary conditions.
I don’t have the background to know whether what Feigel goes on to discuss is workable or not, but I do want to point you to the paper and the recent spate of comments on it. What I can do is farm Feigel’s work out to several Tau Zero practitioners whose expertise in the area of the quantum vacuum will allow them to make an informed judgment. Until then, let’s look at what Feigel says about what some are calling a ‘quantum propulsion machine.’
Feigel’s ‘magneto-electric quantum wheel’ would tap the forces in the quantum vacuum by introducing magneto-electric nanoparticles that would interact with them. Technology Review‘s physics arXiv blog discusses what Feigel is proposing:
The first method is to rapidly aggregate a number of magnetoelectric nanoparticles, a process which influences the boundary conditions for higher frequency electromagnetic waves, generating a force.
The second is simply to rotate a group of magnetoelectric nanoparticles, which also generates a Lorentz force.
Either way, the result is a change in velocity…
The magneto-electric quantum wheel would be what Feigel calls “…an addressable array of small magneto-electric particles or wires” which, upon rotation, would generate a force. Let me quote more fully from the paper:
…mechanical action of [the] quantum vacuum on magneto-electric objects may be observable and have a significant value. Rotation or self-assembly of the nanoparticles is enough to generate a back-action from zero electro-magnetic fluctuations. The amount of momentum that can be extracted from quantum vacuum by this effect may have in the future practical implications, depending on advances in magneto-electric materials.
The applications the author is talking about involve correcting the attitude of satellites in space. These are tiny effects, but the concept, which would involve propulsion that would occur without any loss of mass, is intriguing for that reason alone. Carrying propellant is a huge constraint as we look toward missions into deep space. Most of the vehicle is devoted to fuel tanks — consider Daedalus, or the ongoing Icarus project. Heck, consider Apollo, with its 600 to 1 mass ratio. Leaving the propellant at home is why concepts like Robert Forward’s lightsails can get to a star using known physics.
In the far future, what if we could harness the quantum vacuum to achieve significant propulsion without the huge mass ratio problem? We’re a long way from that, but if Feigel’s ideas are testable, let’s see where they may lead. I’ll hope to be posting further thoughts on this from Tau Zero practitioners soon. The paper is Feigel, “A magneto-electric quantum wheel,” available online.
There is debate about what the quantum vacuum fluctuations actually represent. QM says that there is a lot of energy in these. GR says there is not. That is one paradox. Another is the fact that whatever energy exists in these fluctuations is irrelevant because useful energy comes from a difference between two energy states and the quantum vacuum fluctuations offer only one energy state. The reality is that we still do not have a decent quantum vacuum theory and that, until we do get one, the current descriptions based on QM and GR are going to be incomplete.
There was a discussion of this idea here:
http://james-nicoll.livejournal.com/2173898.html
I thought comments by Matt McIrvin (“mmcirvin”) ought to be considered, but I lacked the background to reply. In that discussion, I did link to another paper, co-authored by Robert Forward, on an unrelated way to build a Casimir Effect spacecraft.
Assuming this idea works, what happens to the momentum absorbed by the vacuum? I can’t imagine that the vacuum would be an infinite momentum sink, absorbing it forever without any noticable effects. Does any energy go into the vacuum in this process? Could the vacuum eventually spit out some particles containing the absorbed momentum and energy?
There are also some additional comments on this paper at:
http://badphysics.wordpress.com/2009/11/15/how-to-time-travel-4/#comments
The whole paper is based on “magneto-electric particles change the momentum of quantum vacuum and, as a consequence they acquire
the resulting difference.” However going through the following paper which references Feigel’s earlier work:
http://arxiv.org/abs/0908.4390
“To our knowledge nor the classical contribution to magneto-electric momentum, neither the QED correction have ever been observed.”
Who’s going to spend the money to test it out?
Cheers, Paul.
I think with respect to energy, things are quite clear. The vacuum, by definition, is the lowest energy state. Useful energy can only be produced by transitioning to a lower state. Thus, no useful energy can be produced from the vacuum, unless it isn’t the vacuum. The logic is quite inescapable, really.
If indeed the vacuum were not a true vacuum, but only a local minimum, we would be foolish to mess with it (assuming we could), because the entire universe might just eagerly switch to the “better” vacuum once we found it, and obliterate us along with everything else. Hey, there would be an elegant solution to the Fermi paradox ….
With respect to momentum, I am not so sure.
The situation could well be analogous to the ocean, where despite the great depth and gigantic weight of the water, we can not extract energy because there is nowhere deeper than the surface for the water to go. However, we can extract momentum at will, and we do, with the help of ship’s propellers.
Another thing that needs to be considered how far this would go in solving the problem. To accelerate to near light speed, we still need a lot of energy. We need to take that energy with us, and the energy itself would be just as massive as any reaction mass. Eliminating the latter still leaves the former, which may yield less of an advantage than we would have hoped. In particular, we would still be constrained by the rocket equation.
After reading around a little, I am now convinced that “taking momentum from the vacuum” is exactly equivalent to the photon rocket. In the ocean analogy, a vacuum momentum propulsion ship must leave a wake. The simplest such wake is light. As one of the commenters referenced above says: I have such a device, it is called a flashlight.
And Larry Niven’s reactionless drive moves one step closer to reality. Awesome.
it is sooo good to see so much intelligent thought going into one of my favorite subjects! imho the very best means of propulsion to move space craft around the galaxy/universe right now are those that seek to develop warp drive,wormholes, – and or the fantastic benefits that could be derived from harnessing the energy of the vacuum!! hope to get alot more concepts advanced soon and right here on the site! looking very much forward to reading and commenting on them. a subject like this is the very heart and soul of a place like tau zero!thank you very much one and all your friend george ps just finished reading,yet again, lol for about the 8th time arthur c clarkes fantastic masterwork “2001 a space odyssey” in it an advanced (to say the least) – alien race defeats the vast cosmic distances by having in operation a grand central terminal type operation of wormholes.what might anyone have to say? by the way as you may know there are 4 books in the 2001 series i currently have them neatly lined up to re read also! i’m about 4 chapters into 2010 right now. again thank you… george
You can not extract any energy from vacuum because it is the lowest energy state, so no vacuum energy perpetuum mobile. and also you can not dump any momentum to vacuum because that would violate lorentz invariance of the vacuum. So no reactionless drive either.
Yeah, I remain highly sceptical, even though my heart knows such a concept would be just the ticket we need to *really* get around our neighbourhood.
However, I’m ready to be impressed (awed, actually) when someone demonstrates a *working* prototype of a reactionless drive. Perhaps a drive pushing a toy train around a track? Show me that, and then show it to me again operating in a near vacuum, and then I’ll eat two hats. And a pair of gloves.
Ric
But it’s not exactly a reactionless drive, is it, if it leaves a wake of light that has the opposite momentum.
Unless light sails / photon drives don’t work…
Well then, how is it different from any other, you know, light source ?
ok guys as usual,with all respect to what i have always found to be a brilliant bunch of guys, T U T – correct me if i am wrong but i thought that it was well established the the vacum is seething with energy in a quantum physics sense.tell me if i am wrong and why please.might i be wrong? it surely can happen. – ric,as to what you said,for some reason it struck me as just the sort of thing that actually happens! i can see the headline now,”princeton professor claims to run lionel train with vacuum energy’!!! tobias,once again correct me if i am wrong but as long as a thing like that did work who cares if it leaves a wake or not? i see it as i am sure alot of others do as “just” a spacecraft moving through space like a red hot knife through butter! am i over enthusiastic? maybe. respects to one and all george
The problem is not that there is no energy. The problem is, that it can not be extracted. Because if you extract energy from somewhere, there will be less energy there afterwards. And the vacuum is the lowest possible energy level, so it by definition can not decrease, and therefore you can take any energy from it.
Errata : and therefore you can NOT take any energy from it.
T U T thank you sir for the answer but i only stopped by for a moment this morning on my way someplace else! i promise i will give it some thought and give you an answer sometime relatively soon.lol “relatively soon” no pun intended! :) your friend george
T U T well,alot of hours have been used up since i promised a relatively speedy answer! thought about it and again maybe i am wrong but the thought occured – space is VAST and if you are flying through it fast enough garnering only a little bit of energy per mile would that not still tend to ad up!? i might be only saying what i want to hear because i like this idea – so i invite any reader here to “give me their reasons” pro or con for vacuum energy. fyi gang i did think that i saw something on the science channel that clearly stated that scientists did have high hopes for this form of energy. i wonder about that.and T U T i will admit this,if you are right then most certainly 0 +0 +0 still would = 0 it is just that i have liked this idea since i first read about it about,i guess 5 to 10 years ago would appreciate any education any body could throw my way! respectfully george
Search for “zero point energy”, and you will find a cesspool of pseudo-science to gorge upon if you like that idea….
I think Mr T_U_T’s already presented his case quite well. In order to profit from energy, you need a difference in potential. Moreover, on the assumption that vacuum-space is at the lowest possible energy level, then yer can’t go from the lowest energy level to a higher energy level without *adding* energy.
I’d like to add my own ha’penny to this Casimir propulsion discussion, based on what I understand by the “classical” two-plate experiment: getting propulsion out of a single plate feels rather like trying to clap with only one hand.
Still, the experiment to prove/refute looks quite straightforward, so I’m sure one of the many researchers that visit here can rustle up the equipment in a jiffy and give it a go. If it works… well, remember it was Uncle Ric that encouraged you during your Nobel Prize acceptance speech.
Ric
George Scaglione writes:
George, Claudio Maccone recommends Thomas Valone’s book Zero Point Energy: The Fuel of the Future as a good backgrounder on these ideas and their history. You can find it here:
http://www.amazon.com/Zero-Point-Energy-Fuel-Future/dp/0964107023/ref=tmm_pap_title_0
Caution, this book is dedicated to Nikola Tesla, the patron saint of pseudoscience. At the risk of judging a book by its cover (or dedication), this is a bad sign. In the aforementioned cesspool, you will often read about how Tesla had all of mankind’s problems solved, before he was done in by the evil conspiracy. You will also read about a lot of devices that are in the final stages before being demonstrated or commercialized, but you will not find a single one that has been, convincingly. So, keep your hand on your wallet…
For the record, I much respect Nikola Tesla, AFAIK he was just unfortunate to fall in with the wrong crowd, posthumously.
Prehumously, don’t you mean. He started to go a bit cuckoo in his old age, like a lot of scientists.
February 01, 2010
Mach Effect Propulsion, IEC Fusion for Space and Heim Theory Updates and More at SPESIF Conference
Full article here:
http://nextbigfuture.com/2010/02/mach-effect-propulsion-iec-fusion-for.html
Have been thinking about the idea of a “quantum propeller” for about five years now and just stumbled across this post. This actually sounds simple and achievable. Instead of pushing a reaction mass, virtual particles can be used as propellant with a rotating disk made of specially constructed magneto-electric nano-particles. Does not violate anything, yet works. Takes this to a well developed level and you’ve got yourself a real flying saucer. The energy requirements for deep space travel are actually rather modest, it has always been the propellant mass that made it impossible.
http://www.technologyreview.com/blog/arxiv/27388/
Giant Casimir Effect Predicted Inside Metamaterials
Exotic materials should lead to new ways of observing and playing with one of the strangest effects in physics, say Chinese physicists.
kfc 12/05/2011
Metamaterials are exotic substances designed to steer electromagnetic waves in ways that are impossible with ordinary stuff. One of their more exciting properties is that they can bend light in a way that is mathematically equivalent to the way spacetime bends light.
This formal equivalence means that metamaterials can reproduce in the lab the exact behaviour of light, not only in our spacetime, but in many others that have only been conjectured until now. This allows physicists to use metamaterials to simulate black holes, big bangs and even multiverses.
Today, Tian-Ming Zhao and Rong-Xin Miao at the University of Science and Technology of China in Hefei use this kind of thinking to make a startling prediction about the Casimir effect inside certain metamaterials.
The Casimir effect arises because our vacuum is filled with a maelstrom of waves that leap in and out of existence at the smallest scales. The best known consequence of this is the well known Casimir force, which pushes together two conducting plates placed close together.
The explanation is that when the distance between the plates is small enough, it can exclude any waves that are too big to fit in the gap. Since there is nothing between the plates to oppose the effect of these waves, they generate a force that pushes the plates together.
This Casimir force operates on a tiny scale, so small that it was only measured for the first time in 1997. But it is not insignificant. At a separation of 10nm, the force is equivalent to 1 atmosphere (although the actual force depends on various factors such as the precise shape of the objects in close proximity).
Of course, the properties of the vacuum waves depend strongly on the medium in which they exist. So it’s not hard to imagine that different spacetimes might have a significant impact on the size of the Casimir effect.
This is exactly what Zhao and Miao show. They say that in a particular kind of electromagnetic space called a Rindler space, the Casimir effect is huge. The essential idea here is that the space can be designed to allow only certain wavelengths to operate. If the electromagnetic properties of the Rindler space are matched to the ambient temperature, then these kinds of thermal waves can be made to dominate the Casimir energy.
That makes the Casimir energy huge. Zhao and Miao calculate that in a lab at 300K (room temperature), the Casimir energy would be some 10^11 times bigger than the free space value. That’s a significant difference that ought to make these effects accessible in an entirely new way to a much broader audience.
Zhao and Miao also say that this kind of material ought to be relatively straightforward to build, layer by layer.
What that means is that it won’t be long before somebody builds this kind of material and shows off the giant Casimir effect for the first time. We’ll be watching.
Ref: http://arxiv.org/abs/1110.1919: Huge Casimir Effect At Finite Temperature In Electromagnetic Rindler Space