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How To Build a Quantum Propulsion Machine

kdawson posted more than 4 years ago | from the magnetoelectric-quantum-wheel dept.

Science 392

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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This can be done using nanoparticles (5, Funny)

Anonymous Coward | more than 4 years ago | (#30402684)

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

Re:This can be done using nanoparticles (2, Funny)

Dachannien (617929) | more than 4 years ago | (#30402758)

Not to mention the International Buttered Toast Society.

Re:This can be done using nanoparticles (0)

Anonymous Coward | more than 4 years ago | (#30402880)

I love the IBTS.

Member since 2003.

Re:This can be done using nanoparticles (0, Funny)

Anonymous Coward | more than 4 years ago | (#30403390)

Nor the People Eating Tasty Animals.

Re:This can be done using nanoparticles (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30402996)

can this thing send knee grows back to AFRICA?

Re:This can be done using nanoparticles (0, Funny)

Anonymous Coward | more than 4 years ago | (#30403198)

Only if you go back to EUROPE.

2nd POST (0, Troll)

Adam7288 (1630001) | more than 4 years ago | (#30402714)

2nd post

So , , , (3, Funny)

DinDaddy (1168147) | more than 4 years ago | (#30402726)

Vacuum doesn't suck, it pushes?

Re:So , , , (2, Informative)

2names (531755) | more than 4 years ago | (#30402816)

Vacuum doesn't suck, it blows?

FTFY. Now queue the Spaceballs jokes.

Re:So , , , (1)

samkass (174571) | more than 4 years ago | (#30403124)

Vacuum doesn't suck-- everything ELSE blows.

Re:So , , , (1)

2names (531755) | more than 4 years ago | (#30403258)

Touché.

Re:So , , , (3, Funny)

Yvan256 (722131) | more than 4 years ago | (#30403222)

Colonel Sandurz: It's Mega Maid. She's gone from suck to blow!

Call me pedantic but... (3, Insightful)

loafula (1080631) | more than 4 years ago | (#30402742)

doesn't the introduction of particles make it NOT a vacuum?

Re:Call me pedantic but... (5, Funny)

seededfury (699094) | more than 4 years ago | (#30402802)

You don't need to vacuum if there are no particles.

Re:Call me pedantic but... (0)

Anonymous Coward | more than 4 years ago | (#30402970)

Ha Ha... you got troll rating for your lame joke attempt!

Re:Call me pedantic but... (0, Funny)

Anonymous Coward | more than 4 years ago | (#30403488)

worthless idiotic mods have no clue what troll actually means. being 12 year olds raging cause wow is patching on their snow day they thought maybe the post was from a low iq green skin.

Re:Call me pedantic but... (0, Offtopic)

AP31R0N (723649) | more than 4 years ago | (#30403054)

i wish i could mod this up, my points just expired.

+1 Funny

Re:Call me pedantic but... (-1, Redundant)

Anonymous Coward | more than 4 years ago | (#30403136)

rofl

Re:Call me pedantic but... (0)

Anonymous Coward | more than 4 years ago | (#30403624)

Vacuums are dangerous [youtube.com]

Re:Call me pedantic but... (5, Informative)

Luyseyal (3154) | more than 4 years ago | (#30402870)

It turns out that there is no such thing as a classical vacuum. Instead, you have a state where particle/antiparticle pairs are spontaneously created and destroyed with typically net zero force. So, the definition of vacuum has been reformed.

-l

Re:Call me pedantic but... (1)

Yvan256 (722131) | more than 4 years ago | (#30403240)

So what you're saying is... it's a rock'n roll vacuum?

Re:Call me pedantic but... (2, Informative)

FTWinston (1332785) | more than 4 years ago | (#30403164)

They're not launching these spinning particles into the vacuum, they're just spinning while attached on the ass-end of your space ship.

Alternatively (if you're talking about the other particles), see the other response.

what are we talking here?! (1, Redundant)

Coraon (1080675) | more than 4 years ago | (#30402744)

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

Re:what are we talking here?! (1, Troll)

qmaqdk (522323) | more than 4 years ago | (#30402888)

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

What problem? Unification with quantum mechanics?

Re:what are we talking here?! (0)

Anonymous Coward | more than 4 years ago | (#30403134)

Uhh...3800361*8?

Re:what are we talking here?! (5, Informative)

JoshuaZ (1134087) | more than 4 years ago | (#30402950)

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).

Re:what are we talking here?! (1)

bmearns (1691628) | more than 4 years ago | (#30403294)

Thanks for the thorough information. How does this throwing off mass thing relate to electric cars? Do electric cars accelerate without loosing mass? If not, they must be loosing mass as the battery discharges, right? So how would this vacuum mobile be any different?

Re:what are we talking here?! (3, Interesting)

tylersoze (789256) | more than 4 years ago | (#30403368)

Well technically the car is losing a slight bit of mass because of the energy change, but that's not relevant to the propulsion, a car isn't a rocket. The car is pushing against the earth and transferring that momentum to the earth.

Re:what are we talking here?! (1)

natehoy (1608657) | more than 4 years ago | (#30403398)

Cars move by pushing round bits called "wheels" against a friction surface called "the ground". So the propulsion system itself is a friction system and does not involve the loss of mass.

The article is talking about this new propulsion system as an alternative to systems that involve losses of mass, like rockets for example.

Re:what are we talking here?! (1)

Myrcutio (1006333) | more than 4 years ago | (#30403580)

electric cars are based on magnetic coils producing a kinetic force. Put an electric car in a zero G vacuum and you won't go anywhere. The difference is that a quantum propulsion engine does not rely on a tangible surface to push against.

Re:what are we talking here?! (1)

JoshuaZ (1134087) | more than 4 years ago | (#30403420)

Er, "conservatin of momentum" forces the rocket backwards not "conservation of mass." I need to learn to use preview.

Those daring men in their quantum pushing machines (5, Insightful)

Anonymous Coward | more than 4 years ago | (#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.

Re:Those daring men in their quantum pushing machi (3, Funny)

FTWinston (1332785) | more than 4 years ago | (#30403186)

Until we find out that if you leave it on for a million years, it might just accelerate a space ship of one cubic centimetre up to a few millimetres per hour.
With due apologies to the authors if this estimate turns out to be a gross underestimate.

Momentum Conservation (3, Interesting)

UnHolier than ever (803328) | more than 4 years ago | (#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!!

Re:Momentum Conservation (4, Informative)

EdZ (755139) | more than 4 years ago | (#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:Momentum Conservation (0, Redundant)

Rising Ape (1620461) | more than 4 years ago | (#30402956)

You can't change the momentum of the vacuum. If the field is carrying momentum and energy, then it's not the vacuum - which is by definition the ground state.

Sounds like nonsense to me.

Re:Momentum Conservation (2, Informative)

Sir_Lewk (967686) | more than 4 years ago | (#30403144)

If you would read the article (a high order, I know), you would realize that, with quantum mechanics taken into consideration, there is no such thing as a classical vacuum. Hell, you could probaby get that just from reading the summary.

Re:Momentum Conservation (1)

Rising Ape (1620461) | more than 4 years ago | (#30403292)

Yes, I know that. In fact, I already knew that. What I said is still valid for the quantum vacuum - even when the ground state has a non-zero vacuum expectation value, it still has no direction of any kind. Hence, no momentum. "Pushing the vacuum" would mean exciting it to a state where it wasn't the vacuum any more, e.g. by creating photons and directing them out of the back of the rocket. Now that's fine, but hardly revolutionary.

Re:Momentum Conservation (1)

CroDragn (866826) | more than 4 years ago | (#30403586)

My understanding is that the virtual vacuum particles for an instant, act like any other particle, annihilate each other, and vanish. So this would essentially be "pushing" against the particles during the instant they exist, but as they then proceed to pop out of existence the next moment it's essentially as if the engine is pushing against nothing.

Re:Momentum Conservation (4, Insightful)

radtea (464814) | more than 4 years ago | (#30403456)

You can't change the momentum of the vacuum.

"You can't see moons around Jupiter. If there were, it would mean the Earth isn't the center of the universe." (Galileo's critics really said this.)

"You can't sail across the Atlantic to China. If you could, it would mean the Earth was round" (many, many errors on all sides of that statement!)

"Anyone who is talks about the practical uses of nuclear power is talking moonshine" (Rutherford in 1920, more-or-less.)

Scientific progress is the process of tearing down previously believed truths as well as discovering new, hopefully somewhat less contingent truths (although of course non-zero contingency always remains, which is a big deal to philosophers,mathematicians and other insane people, but not something anyone else cares very much about.)

People who have done actual calculations, rather than an arm-chair analysis on /., think that it is possible to change the momentum of vacuum modes, thereby making them non-vacuum modes (one would presume) by introducing asymmetries from rotating magneto-electric materials and in various other ways.

Introducing asymmetries has long been know to produce real particles from the vacuum. One of the most dramatic theoretical instances of this is a step-function potential with more than twice the electron mass. If you solve the Dirac equation in this situation you get weird phenomena like negative transmission and reflection coefficients that are negative or greater than unity.

The explanation is that such a large potential (so long as the step occurs over a scale of less than the Compton wavelength of the electron, which is about a pico-metre) has the ability to separate the virtual pairs that make up the "Dirac sea", thus turning them into actual particles (at the cost of the required amount of energy). If you could actualize this you could then accelerate the electron and positron to fire them off in the same direction, giving your apparatus a push in the process. At the most abstract level, what these guys are proposing is no different from that.

Re:Momentum Conservation (2, Informative)

david.given (6740) | more than 4 years ago | (#30403236)

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 publishable --- you may not that it's incredibly well referenced.

I hope someone tests this soon; it sounds easy to do, and if it's true, it'll be an incredible breakthrough. Apart from producing awesome space drives it would also provide a way of coupling energy to momentum. As energy has dimensionality MASS.DISTANCE^2.TIME^-2 and momentum has dimensionality MASS.DISTANCE.TIME^-1, that would open up whole new areas of science to pick apart.

Re:Momentum Conservation (1)

david.given (6740) | more than 4 years ago | (#30403360)

To EdZ: also, your parent just popped up and I realised you were actually replying to someone else. Er, oops! Sorry.

Re:Momentum Conservation (1)

meringuoid (568297) | more than 4 years ago | (#30403406)

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?

Re:Momentum Conservation (0)

Anonymous Coward | more than 4 years ago | (#30402878)

ianap but...

as they're not venting anything to "push" against these "particles" they maintain a constant mass which is where i believe it relates to momentum conservation... i think you're using the casimir effect as a red herring... with a fricking "laser" on it's head (sorry couldn't resist after the first use of double quotes)

Re:Momentum Conservation (1)

tylersoze (789256) | more than 4 years ago | (#30402892)

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?

Re:Momentum Conservation (1)

tylersoze (789256) | more than 4 years ago | (#30403042)

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?

Re:Momentum Conservation (1)

fyngyrz (762201) | more than 4 years ago | (#30403300)

Really? When magnetic fields repel each other, are there photons being expended?

Just asking - I don't know. I thought that magnetic fields weren't made up of photons, but from your post, that's wrong?

Re:Momentum Conservation (1)

tylersoze (789256) | more than 4 years ago | (#30403432)

Yes that's correct, virtual photons. A photon is the carrier of the electromagnetic force and is the quanta that makes up the field, so any electromagnetic interaction can be thought of as an exchange of virtual photons, that is, photons that appear spontaneously out of the vacuum. http://en.wikipedia.org/wiki/Virtual_particle [wikipedia.org]

Re:Momentum Conservation (1)

tylersoze (789256) | more than 4 years ago | (#30403542)

And to add to that, "real" photons are what make up electromagnetic waves, which are propagating changes in the electromagnetic field. http://en.wikipedia.org/wiki/Electromagnetic_radiation [wikipedia.org]

Re:Momentum Conservation (0)

Anonymous Coward | more than 4 years ago | (#30403506)

Really? When magnetic fields repel each other, are there photons being expended? Just asking - I don't know. I thought that magnetic fields weren't made up of photons, but from your post, that's wrong?

They aren't made up of photons, but photons are exchanged when force is exchanged.

Re:Momentum Conservation (0)

Anonymous Coward | more than 4 years ago | (#30402988)

The law of conservation of momentum was repealed in 1905.

Re:Momentum Conservation (1)

jameskojiro (705701) | more than 4 years ago | (#30403090)

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

Re:Momentum Conservation (0)

Anonymous Coward | more than 4 years ago | (#30403386)

Energy might be converted to motion in + and - one direction, but never in just + or - one direction, because that would violate Newton's third law of motion:

"For every action there is an equal and opposite reaction."

Re:Momentum Conservation (1)

jameskojiro (705701) | more than 4 years ago | (#30403410)

What if the opposite reaction is the release of thermal energy in all directions?

Re:Momentum Conservation (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30403120)

Uh WTF retard flagged the parent as "offtopic"? That's a completely valid point.

Fourmilab (5, Informative)

Red Jesus (962106) | more than 4 years ago | (#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.

Re:Fourmilab (1)

morgan_greywolf (835522) | more than 4 years ago | (#30403092)

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.

Yep. You're using the forces generated by quantum effects to propel yourself forward, like a submarine uses water to propel itself forward. It's the closest you're going to get to a car analolgy.

Someone should send this link to John. He'd like it.

Re:Fourmilab (1)

Sir_Lewk (967686) | more than 4 years ago | (#30403364)

It's the closest you're going to get to a car analolgy.

Oh come on now, you can do better than that.

What they've done is create something that spins around, and in the process pushes off of something else, generating propulsion.

In other words.... They just invented the space-wheel! The question of powering the spinny parts is still up in the air, you'll need some sort of engine. The parallels to automobiles should be obvious to any experianced slashdotter. :)

Mod up: parent's article is critical (1)

cpu_fusion (705735) | more than 4 years ago | (#30403102)

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.

Re:Fourmilab (1)

LordAndrewSama (1216602) | more than 4 years ago | (#30403188)

Let's just hope he doesn't screw everyone over by patenting it ;)

MOD PARENT UP (4, Insightful)

LanMan04 (790429) | more than 4 years ago | (#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.

Is this different from a photon drive (4, Interesting)

stevelinton (4044) | more than 4 years ago | (#30402934)

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.

Re:Is this different from a photon drive (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30403048)

8=======D

Probably the only chance there is (2, Interesting)

Anonymous Coward | more than 4 years ago | (#30402960)

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 Solar system that you're aimed exactly right. However, if there is something to push against, problem 2 is solved.

Re:Probably the only chance there is (1)

jameskojiro (705701) | more than 4 years ago | (#30403110)

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

Re:Probably the only chance there is (0)

Anonymous Coward | more than 4 years ago | (#30403270)

Something to push against? Hunh? .. mass for propulsion to make it there ...? Hunh? again. Once you're up to speed, you switch off and coast.

Implications? (0)

Anonymous Coward | more than 4 years ago | (#30402986)

" it generates propulsion without any change in mass. As the research puts it with magesterial understatement, this might have practical implications"

Ok, I'll bite: someone want to tell me what those implications are?

Re:Implications? (4, Insightful)

Hal_Porter (817932) | more than 4 years ago | (#30403242)

Well you're not going to get to a decent fraction of light speed if you need to squirt stuff out of the back of a rocket. A propulsion system that doesn't depend on squirting stuff out of the back of the ship opens up all sorts of possibilities.

E.g. a spaceship that could accelerate at 1g would have all sorts of useful properties. Firstly 1g feels like gravity. Secondly you could zip around the solar system pretty quickly. Last but not least, due to time dilation you could circumnavigate the known universe in 50 to 100 years ship time. Of course back on Earth millions of years would pass so the trip would be one way. Still you could imagine making decades long (I guess, I'm too lazy to do the math) trips to a star like Sirius.

Actually I like the idea of sending out a plague of self replicating machines in devices like these, to bring the Word Of Dawkins to the stars and troll the inhabitants of other star systems.

Re:Implications? (5, Informative)

fyngyrz (762201) | more than 4 years ago | (#30403582)

If a spacecraft carries reaction mass, the total mass of the spacecraft is increased by the amount it is carrying at any one time. This mass must also be accelerated and decelerated. So the more you carry, the more you spend because you're carrying it. There are various side effects too, for instance, since the vehicle's mass changes over time, course change calculations have to keep track of that. Also, for every bit of mass you have to carry that is fuel, that's less cargo you can move from point A to point B.

If you have an energy source that is relatively mass constant - a nuclear reactor, or a set of solar panels - and you can piddle along without any tanks full of "stuff", you're going to be able to carry more payload; you're going to be able to go a lot longer without "refueling"; you're going to have more freedom and more range. Headed for asteroid X? Something interesting over there on Asteroid Y? No bothersome fuel constraints, you just go and take a look. That's the kind of benefit that has very positive ramifications.

The reason reaction mass is used in space is because in a vacuum, one has to push against something in order to move. That's the role of the reaction mass. You spend energy in X direction and get sent off in the -X direction with the same amount of energy.

Think of how a nuclear sub works underwater. Because it has something to push against (water), its ability to move is constrained only by the degree of push it can generate - it doesn't have to carry anything to push against, it's surrounded by water that will serve the purpose. The reactor provides a lot of energy to push with, using a propeller, which is designed so as to create a forward vectored force when spinning in the water. That's what the article suggests for space craft; that there is something there to push against, and therefore, one doesn't need to carry reaction mass. Spaceships using this method would be very much analogous to that nuclear submarine.

Finally! (2, Funny)

Anonymous Coward | more than 4 years ago | (#30403060)

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

Any Physicists here? (1)

Hal_Porter (817932) | more than 4 years ago | (#30403104)

Will this gizmo work? A reactionless drive almost sounds too good to be true.

Boy did I read that headline wrong (3, Funny)

HangingChad (677530) | more than 4 years ago | (#30403108)

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.

Re:Boy did I read that headline wrong (1)

sukotto (122876) | more than 4 years ago | (#30403194)

That would make a great name for a "They Might Be Giants" tribute band.

Re:Boy did I read that headline wrong (1)

Again (1351325) | more than 4 years ago | (#30403256)

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 (2, Interesting)

kvezach (1199717) | more than 4 years ago | (#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:Reactionless drives (0)

Anonymous Coward | more than 4 years ago | (#30403284)

Yeah right. Like some terrorists would use a propulsion system as a weapon. And what, fly it into a building or two? Nonsense!

Re:Reactionless drives (2, Insightful)

MozeeToby (1163751) | more than 4 years ago | (#30403324)

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:Reactionless drives (0)

Anonymous Coward | more than 4 years ago | (#30403544)

That is, unless you wanted an *anonymous* weapon. For that, tungsten telephone poles traveling at .99c sure seems like the way to go.

Re:Reactionless drives (1)

Monkeedude1212 (1560403) | more than 4 years ago | (#30403384)

Unless we use the Earth AS our ship.

Re:Reactionless drives (1)

KlomDark (6370) | more than 4 years ago | (#30403636)

What, you're some kind of cowardly puppeteer [amazon.com] ?

Re:Reactionless drives (1)

david.given (6740) | more than 4 years ago | (#30403428)

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:Reactionless drives (2, Interesting)

Hurricane78 (562437) | more than 4 years ago | (#30403466)

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 why/how the symmetry is not violated because of something weird.

But why do you have to think of weapons? What you said could be said about nukes too. But it did not change much, because 1. Others will have that weapon too, and 2. To what planet will you go back after destroying it? You know... To breathe! ^^

Nadesico? (2, Insightful)

certron (57841) | more than 4 years ago | (#30403170)

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.

Re:Nadesico? (1)

Suiggy (1544213) | more than 4 years ago | (#30403572)

You get to burning!

there is a change in mass (0)

Anonymous Coward | more than 4 years ago | (#30403220)

If this propels you, you get closer to the speed of light; as you approach that speed, you gain mass.

First Lesson in Relativity... (1)

Roger W Moore (538166) | more than 4 years ago | (#30403230)

"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 show this I do not see anything to be excited about.

Re:First Lesson in Relativity... (1)

adipocere (201135) | more than 4 years ago | (#30403504)

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, and that makes the energy required go up. No dragging along big tanks of propellant with you. It might be quite liberating.

Vindication! (1)

overshoot (39700) | more than 4 years ago | (#30403238)

At last a theoretical basis for the Dean Drive [wikipedia.org] .

Solving a solved problem (0)

Anonymous Coward | more than 4 years ago | (#30403252)

The Norwegians already have a wormhole to the other side of the galaxy, why are we wasting time on this?

from Peter to Paul (1)

oldhack (1037484) | more than 4 years ago | (#30403280)

This sounds like HHGG's cretins travelling back in time to steal stuff from the past, only to find out the future bastards are doing the same to them.

Why did noone tell me it was the future? (4, Interesting)

Nadaka (224565) | more than 4 years ago | (#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.

Sorry to burst bubbles (0)

Anonymous Coward | more than 4 years ago | (#30403392)

But it looks like from the abstract that it will only cause rotational forces. Based off of that it will work similar to a magnetic torque rod or a momentum wheel and not actually be used for moving us about the galaxy.

http://arxiv.org/abs/0912.1031v1/ [arxiv.org]

Conservation of M/E? (1)

JSBiff (87824) | more than 4 years ago | (#30403422)

"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.

Re:Conservation of M/E? (1)

JSBiff (87824) | more than 4 years ago | (#30403600)

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?

Micro Version of an Old Experiment? (0)

Anonymous Coward | more than 4 years ago | (#30403430)

There WAS the attempt to take advantage of the fact that buttered bread always lands butter-side down, and cats always land on their feet.

IIRC, it involved strapping a cat to a slab of buttered toast with the cat's feet on the butter. (Difficulty: obtaining catly cooperation). The early results were promising, with the cat hovering (and spinning) as the cat's feet and the buttered toast fought for landing position. When last heard from, the lab was attempting the same thing with a mountain lion, in the hopes of lifting or stabilizing significant amounts of weight and possibly obtaining propulsion effects by varying cat and bread sizes, with the goal of reaching low-earth-orbit without fuel.

It would require a change of mass (0)

Anonymous Coward | more than 4 years ago | (#30403468)

Casimir effect is real and can be used for propulsion but it would require a change of mass because momentum has to be conserved. The mass variation for unit of time would be equivalent to dm = dE/c^2 where dE is the energy required for propulsion. The thing will move but slow and consume lots of energy. Yet it is an interesting device.

Understatement (0)

Anonymous Coward | more than 4 years ago | (#30403598)

If this ever does get made into a propulsion system that changes the world(s), the phrase "this might have practical implications" will be up there alongside "one small step for man".

Bad Ass! (0)

Anonymous Coward | more than 4 years ago | (#30403632)

Let's do this shit. I'm ready for awesome intergalactic adventures. extrogalactic as well.

Doesn't sound exciting at all... (1)

Monkeedude1212 (1560403) | more than 4 years ago | (#30403642)

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."

My Engine does not change it's mass when it turns the crank shaft. It simply alters the mass of my fuel source. This propulsion system will still require a source of energy. Until we learn how to create energy without a change in mass - this engine is about the same as any other engine. Personally, I don't trust anything with "Quantum" in the name to function anymore then my decade old Car engine.

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