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How To Build a Quantum Propulsion Machine 392

Posted by kdawson
from the magnetoelectric-quantum-wheel dept.
KentuckyFC writes "According to quantum mechanics, a vacuum will be filled with electromagnetic waves leaping in and out of existence. It turns out that these waves can have various measurable effects, such as the Casimir-Polder force, which was first measured accurately in 1997. Just how to exploit this force is still not clear. Now, however, a researcher at an Israeli government lab suggests how it could be possible to generate propulsion using the quantum vacuum. The basic idea is that pushing on the electromagnetic fields in the vacuum should generate an equal and opposite force. The suggestion is that this can be done using nanoparticles that interact with the vacuum's electric and magnetic fields, generating the well-known Lorentz force. In most cases, the sum of Lorentz forces adds up to zero. But today's breakthrough is the discovery of various ways to break this symmetry and so use the quantum vacuum to generate a force. The simplest of these is simply to rotate the particles. So the blueprint for a quantum propulsion machine described in the paper is an array of addressable nanoparticles that can be rotated in the required way. Although such a machine will need a source of energy, it generates propulsion without any change in mass. As the research puts it with magesterial understatement, this might have practical implications."
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How To Build a Quantum Propulsion Machine

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  • by Anonymous Coward on Friday December 11, 2009 @12:06PM (#30402684)

    I bet this could be done even easier with cats, but the ASPCA people won't like it.

    • Re: (Score:3, Funny)

      by Dachannien (617929)

      Not to mention the International Buttered Toast Society.

  • So , , , (Score:3, Funny)

    by DinDaddy (1168147) on Friday December 11, 2009 @12:10PM (#30402726)

    Vacuum doesn't suck, it pushes?

  • by loafula (1080631) on Friday December 11, 2009 @12:11PM (#30402742)
    doesn't the introduction of particles make it NOT a vacuum?
  • Einstein had a theory about changing mass...are they saying they might have licked the problem of relatively?!
    • Re: (Score:2, Troll)

      by qmaqdk (522323)

      Einstein had a theory about changing mass...are they saying they might have licked the problem of relativity?!

      What problem? Unification with quantum mechanics?

    • by JoshuaZ (1134087) on Friday December 11, 2009 @12:25PM (#30402950) Homepage

      That's not at all connected. What you are thining of is as velocity of an object increases its mass will increase (this is actually a little more complicated. This is only true for things with positive rest mass. If you have zero rest mass for example then this doesn't happen, but you will always be traveling at the speed of light anyways. If you are a tachyon and hus have imaginary rest mass and move faster than the speed of light in a vacuum then what happens as you change velocity is more complicated). This will still happen. The key to this sort of drive is that you don't *lose* mass as part of your reaction. Rockets, ion engines, and pretty much every other method of moving things requires you to push against something else to move. A rocket works by sending out particles from one end and so conservation of mass forces it in the other direction. An ion engine works the same way but instead of using hot fast particles uses little ions accelerated by a magnetic field.

      The key to this sort of engine is that it doesn't do that, It can accelerate without throwing off mass. But the object will still gain mass as it accelerates nearer to the speed of light. In practice, the second part really won't matter for any practical engine since we will be moving so much slower than the speed of light. The key idea at some level is that you don't need to lose fuel to accelerate (you just lose energy).

      • by JoshuaZ (1134087)
        Er, "conservatin of momentum" forces the rocket backwards not "conservation of mass." I need to learn to use preview.
  • by Anonymous Coward on Friday December 11, 2009 @12:12PM (#30402754)

    Well.

    A non-reaction mass drive. That makes my head hurt. It just gave a slight air of plausibility to a few million bad SF novels.

  • by UnHolier than ever (803328) <unholy_@h[ ]ail.com ['otm' in gap]> on Friday December 11, 2009 @12:13PM (#30402762)
    How does this preserve momentum conservation? In the Casimir effect, the force occurs between two plates; as the plates are pushed in opposite directions, total momentum is conserved. Here, it seems as though you get momentum out of thin air (although energy is reffered to as "being spent", but with no indication how).

    I call shenanignans!!
    • by EdZ (755139) on Friday December 11, 2009 @12:17PM (#30402814)
      If you, you know, read the article, you'd know they're changing the momentum of the electromagnetic fields in a quantum vacuum. Thus, momentum is conserved.
      • Re: (Score:3, Informative)

        by david.given (6740)
        I did read the article (well, the non-mathematical bits). I quote:

        Quantum fluctuations of the position or of the magneto-electric constant of particles do not affect the average value of their momentum, as a consequence of the conservation of momentum law. A propulsion engine may be designed by using for instance an addressable array of small magneto-electric particles or wires. Rotating (see Fig. 1) or aggregating (see Fig. 2) these particles will result in velocity:

        He brings up attitude control of satellites as an example because, I think, it's a situation where very small amounts of momentum do useful work (you only need to rotate the satellite by a degree or so a day, he says). He's definitely talks about propulsion in the body, not just orientation.

        As reactionless drives are very much Weird Science, not mentioning propulsion in the abstract could well be entirely deliberate to make the article more

        • by david.given (6740)
          To EdZ: also, your parent just popped up and I realised you were actually replying to someone else. Er, oops! Sorry.
      • If you, you know, read the article, you'd know they're changing the momentum of the electromagnetic fields in a quantum vacuum.

        So, they're pushing on photons? I wonder if this is going to end up equivalent to a photon rocket: wonderful if you're trying to save on reaction mass, terrible if you're trying to save on energy?

    • by tylersoze (789256)

      My thoughts exactly. Not to mention if "energy is being spent" that means the mass of the object is decreasing (i.e. the whole mass-energy equivalence thing). If this effect is actually real, then somehow there's still energy being thrown out in the opposite direction to conserve momentum, so I'm not sure how it would be any different than any other form of propulsion. The only advantage I could see is that perhaps using this effect produces a higher specific impulse than other modes of propulsion?

      • by tylersoze (789256)

        OK from the article they're "changing the momentum of the electromagnetic fields in a quantum vacuum". Basically that just means they're throwing photons out the back. That is still going to decrease the rest of mass of whatever it is that powering it. So what's the specific impulse of this method?

    • You are simply converting potential electrical energy into real kinetic energy that is vectored in one direction.

  • Fourmilab (Score:5, Informative)

    by Red Jesus (962106) on Friday December 11, 2009 @12:15PM (#30402792)
    John Walker called such a device a vacuum propeller [fourmilab.ch]. He didn't have any particular ideas about how the device would work, but he does have a nice analogy involving propellers.
    • John Walker called such a device a vacuum propeller [fourmilab.ch]. He didn't have any particular ideas about how the device would work, but he does have a nice analogy involving propellers.

      The article Red Jesus linked is critical. It helped me understand the whole point of this Story. I know I shouldn't RTFA, but I couldn't help it this time.

    • MOD PARENT UP (Score:5, Insightful)

      by LanMan04 (790429) on Friday December 11, 2009 @01:01PM (#30403578)

      This is exactly what they're saying. A quantum propeller.

      You push off of stuff that already exists in space to move forward, instead of having to throw stuff backwards to move forward.

      The KEY is that space is not a true vacuum. It is a "working fluid" in the sense that you can push at it with magnetic fields. It can be interacted with.

    • Given that there is little friction in space, I wonder if it would be possible to generate and store energy when slowing down at the end of the journey (like a hybrid car) and use it to accelerate back up to speed again on the next trip.

      This would dramatically reduce the overall energy consumption, but would need some serious energy storage capacity.

  • by stevelinton (4044) <sal@dcs.st-and.ac.uk> on Friday December 11, 2009 @12:24PM (#30402934) Homepage

    Is dumping momentum into the quantum vacuum different from emitting photons carrying the same momentum? If not, this is just a photon drive, which is a well known concept, has brilliant specific impulse but is incredibly energy-inefficient except at high relatavistic velocities.

    • by LanMan04 (790429) on Friday December 11, 2009 @01:08PM (#30403694)

      Red this short article about "vacuum propellers" (props to RedJesus for finding the article):

      http://www.fourmilab.ch/documents/vprop/ [fourmilab.ch]

      You don't have to "emit" anything, you just set up magnetic fields to push against the "vacuum" of space, which is not at all a true, classical vacuum (it contains little fields all over the place). It's like the ocean, a force that can be interacted with. A "working fluid".

      And since we're talking electromagnetism, a really strong force in the grand scheme of things, maybe this will be a lot of energy efficient that simply throwing almost-massless particles out your rear.

      • Re: (Score:3, Informative)

        by stevelinton (4044)

        I did read that article. It didn't answer the question. The quantum vacuum consists of (at the energy levels we're dealing with) virtual photons. If we're giving net momentum to these virtual photons I think that is the same thing as there being real photons travelling in the appropriate direction. So, you move some charges and magnetic dipoles around, and you photons start moving -- how is this different from emitting something from an antenna?

        And all electromagnetic forces are carried by photons so there

      • by DragonWriter (970822) on Friday December 11, 2009 @02:22PM (#30404788)

        And since we're talking electromagnetism, a really strong force in the grand scheme of things, maybe this will be a lot of energy efficient that simply throwing almost-massless particles out your rear.

        Since it is a momentum-transfer (hence, reaction) drive, it would seem to face the same constraints as any such drive imposed by conservation of energy, so in the ideal case, it would perform exactly the same as an ideal photon drive. Of course, engineering efficiencies might, in practice, favor one over the other, but even an ideal photon drives has an enormous input power to thrust ratio on the order of 300MW per Newton of thrust.

  • by Anonymous Coward

    Something like this is probably the only chance there is for interstellar space travel. The two biggest problems in traveling between stars are first having a source of energy that will last long enough to make it there, and second having the mass for propulsion needed to make it there. Between stars, there's not a lot you can push against so you have to carry your mass with you, and for corrections on an interstellar flight that could add up to a lot of mass. Either that or hope when you shoot out of the S

    • Forget Interstellar travel if we can open up interplanetary travel at the very least it is a good thing.

  • Finally! (Score:2, Funny)

    by Anonymous Coward

    ZPM's! We'll be able to retire the aging buttered cat array [deepscience.com] fleet!

  • by HangingChad (677530) on Friday December 11, 2009 @12:33PM (#30403108) Homepage

    How To Build a Quantum Propulsion Machine

    At first glance I thought it said How To Build a Quantum Popsicle Machine. Then I thought Quantum Popsicle would have been a great name for a hair band in the 80's.

    You could have flavors like Lime Quark and Strange Berry, put the stand up outside the Hadron Collider.

    • by sukotto (122876)
      That would make a great name for a "They Might Be Giants" tribute band.
    • by Again (1351325)

      How To Build a Quantum Propulsion Machine

      At first glance I thought it said How To Build a Quantum Popsicle Machine. Then I thought Quantum Popsicle would have been a great name for a hair band in the 80's.

      Except we reached Peak Spandex in 1992 so this idea will never be accepted.

  • Reactionless drives (Score:3, Interesting)

    by kvezach (1199717) on Friday December 11, 2009 @12:34PM (#30403130)
    If I'm reading the summary right, that's basically a reactionless drive: a device that can accelerate in space without having to throw anything out the back.

    A reactionless drive would be nifty because it can gather kinetic energy very easily (that's what makes travel so cheap with one). However, there's a darker side to that coin. If you can accelerate a ship to near-c with little difficulty, there's not much stopping you from extorting the Earth by threatening to drop the ship (or for that matter, a bunch of tungsten telephone poles traveling at .99c) on them.

    Any propulsion system can be used as a weapon. Thus, the good news of the reactionless drive is that one can easily move about in space. The bad news is that one will have to.
    • Re: (Score:3, Insightful)

      by MozeeToby (1163751)

      Considering most other forms of theoretical space propulsion are accomplished with either controlled explosions (the bigger the better) or exceedingly large lasers, this seems relatively safe. Besides, sending something up to .99c still takes an extreme amount of energy, even if the system were 100% efficient (which I highly doubt) getting any sizable object up to that speed is going to take a massive power supply; massive enough that it could probably have been used more directly if you wanted a weapon.

      • Re: (Score:3, Insightful)

        by david.given (6740)

        Just out of interest:

        A telegraph pole is ~10m long and about ~0.2m wide. Cross section: 0.03m^2. Volume: 0.3m^3.

        The density of tungsten is 19300 kg m^-3, so your tungsten telegraph pole masses about 6000kg.

        The relativistic momentum of an object is (m v) / (1 - v^2 / c^2)^-2: 13e13 Ns.

        The relativistic kinetic energy of a mass is (p^2 c^2 + m^2 c^4)^-2, where p is the momentum: 4e21 joules.

        Assuming I've got my maths right, which given that it's late on Friday afternoon is highly questionable, that i

    • Unless we use the Earth AS our ship.

    • by david.given (6740)

      If you can accelerate a ship to near-c with little difficulty, there's not much stopping you from extorting the Earth by threatening to drop the ship (or for that matter, a bunch of tungsten telephone poles traveling at .99c) on them.

      Well, you could.

      Alternatively, since all that kinetic energy doesn't come out of nowhere, you'd still need to supply a really huge battery. And if you've got one of those, there's probably more convenient ways to use it to kill people than all that inconvenient fiddling about with spaceflight.

    • Re: (Score:3, Interesting)

      by Hurricane78 (562437)

      Uuum, wouldn’t it be more like a machine that constantly digs up some soil, and throws it behind itself, to accelerate?

      Of course, here the “soil” constantly digs itself up. But you’re still “taking that “stuff”, and throwing it behind yourself. It just happens to zero itself out after this, if I understand it correctly.

      I would bet money, that we will get some very interesting effects and new science out of even trying this.
      Like finding out why it does not work. Or w

  • Nadesico? (Score:2, Insightful)

    by certron (57841)

    This sounds a whole lot like the way the engines work in the anime Kidou Senkan Nadesico. There's even a helpful animation played to explain it all to the crew and passengers.

  • "Although the proposed engine will consume energy for manipulation of the particles, the propulsion will occur without any loss of mass," says Feigel.

    I'd like to see how that works. The one thing that even non-physicists know is that energy is equivalent to mass (E=mc2). This applies to all power. However the mass loss of a battery which discharges is negligible compared to the total mass hence it is usually neglected for energies below nuclear. Unless they can show otherwise my very strong suspicion is that they energy needed to manipulate the nano-particles will be identical to the energy needed to emit a photon of the same momentum. Until they can sh

    • by adipocere (201135)

      I see plenty to be excited about. For one, you're not having to chuck stuff out the back. With a rocket, you are carrying your reaction mass along with you. You're not only having to accelerate your ship, you're having to accelerate the stuff you'd just gonna throw out the rear a few minutes from now. It means that ships are very heavy and inefficient.

      With this, you're just concerned about your energy. Without it, you're concerned about your energy, and the extra mass you have to carry along with you,

  • At last a theoretical basis for the Dean Drive [wikipedia.org].
  • by Nadaka (224565) on Friday December 11, 2009 @12:50PM (#30403366)

    Does it mean that I am old because I look around every day and it feels like I am living in a surreal sci-fi story?

    Reactionless drives, energy weapons, smart phones, robotic killing machines, genetically engineered super species? At this rate I wonder if I would be surprised when practical AI or faster than light travel becomes an option.

  • "According to quantum mechanics, a vacuum will be filled with electromagnetic waves leaping in and out of existence."

    I'm confused. . . does this violate the law of the Conservation of Matter & Energy? Can this effect be exploited to harness 'free' energy? After all, electromagnetic waves are energy, are they not? Sure, propulsion that doesn't require you to throw stuff out the back door sounds interesting, but free energy sounds even more interesting.

    • by JSBiff (87824)

      After perusing the linked Wiki article about Vacuum, I suppose what it comes down to is that the energy potential in vacuum is so incredibly small, it's not worth trying to exploit?

    • Re: (Score:3, Informative)

      by wizardforce (1005805)

      No. Think of the virtual particles as a loan that *must* be repaid. The more that is loaned, the quicker that it must be repaid. electron/positron virtual pairs exist for a loner time than say virtual proteon/antiproton pairs do. There is no way to use the creation of virtual pairs to create free energy or break the conservation laws.

  • by Locke2005 (849178) on Friday December 11, 2009 @01:24PM (#30403940)
    First, assume you have a magnetic monopole. From there, the math is easy.
  • See this item from 2004: [erols.com]

    He started with the fact that electrical and magnetic forces between objects are mediated by photons that flit between them. So an object placed in strong electric and magnetic fields can be considered to be immersed in a sea of these transitory, virtual photons.

    Feigel then showed that the momentum of the virtual photons that pop up inside a vacuum can depend upon the direction in which they are travelling. He concludes that if the electric field points up and the magnetic field points north, for example, then east-heading photons will have a different momentum from west-heading photons.

    So the vacuum acquires a net momentum in one direction — it’s as though the empty space is ‘moving’ in that direction, even though it is empty.

    It is a general principle of physics that momentum is ‘conserved’ — if something moves one way, another thing must move the other way, as a gun recoils when it shoots a bullet. So when the vacuum acquires some momentum from these virtual photons, the object placed within it itself starts to move in the opposite direction.

    Feigel estimates that in an electric field of 100,000 volts per metre and a magnetic field of 17 tesla — both big values, but attainable with current technology — an object as dense as water would move at around 18 centimetres per hour.

  • by Interoperable (1651953) on Friday December 11, 2009 @04:17PM (#30406238)

    The paper is a one-author publication in a non-peer-reviewed journal and doesn't seem to be published anywhere else. The author's affiliation is an applied R&D institute not an academic institute with a strong theoretical background. I'm not saying that discredits it, but it certainly means that it should be taken with a grain of salt. I would suggest that anyone who wants to assess the merits should read through some of the references (which are good publications) and see if the present article appears plausible. Even without any technical expertise, the abstracts could probably provide a feel for the state of the art.

    I couldn't be bothered to do that reading myself, but I would suggest that any momentum transfer to the vacuum would involve the production of real particles from the zero-point fluctuations. Conservation of momentum demands that there would be something carrying momentum in the opposite direction of the spacecraft and, by definition, it can't be an unexcited quantum field. There would have to be excitations of the field to carry the momentum (real particles).

  • Hybrid space ships! (Score:3, Interesting)

    by Chirs (87576) on Friday December 11, 2009 @06:55PM (#30408098)

    Something that nobody has mentioned yet is that if we're coupling to the surrounding vacuum to accelerate ourselves, we should be able to couple to the vacuum to decelerate ourselves, _and store the energy from the deceleration_.

    Given big enough energy storage devices, we can then use that energy to accelerate on the next trip, and the net energy cost per trip is substantially reduced.

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