Solar sails are not in violation of the conservation of momentum, you don't have to carry the reaction mass though, you have the sun throw it at you instead. So if fuel is defined as stuff you gotta keep in tanks on board, then solar sails are indeed thrust-without-fuel.
However, if we would like our physical universe to behave the same no matter where you are - the translational symmetry of the physical universe - then you're stuck with the conservation of momentum. It really looks much more fundamental than any of our fiddling around with quantum electrodynamics, for example. Even if that does enjoy the auspicious acronym of QED. The claim is that this thing accelerates itself without any reaction mass of any kind, which is, simply put, not actually possible. That, with the addition that the effect is borderline unmeasurable, makes the whole think look very very much like, if not a hoax, then at least an elaborate error.
In that case, I agree somewhat. Carl Sagan wrote a great book about space exploration, called Pale Blue Dot. It is by turns optimistic, and hopeless. You could build such a ship, but it's not clear that we could sustain human life in the vacuum (and hard radiation) of space for the thousands of years that it would take to make the trip. There's a nice science fiction story by Brian Aldiss that's sorta about the same thing - called "Non Stop". I'm not sure civilisation on board that ship would survive the trip, even if the ship itself did.
Sorry for replying out of context. I'd just watched The Neon Demon, I was a bit out of sorts:).
Binary man is actually right, though. You don't get to violate the conservation of momentum, because then you have a free energy machine. He may be a bit of a dick, but he is right.
Poor 1101010101, or whatever his (or her) name is. He (or she) means Laws, not Theories. The Laws are immutable, the theories are a bunch of math that seems to work alot of the time.
The Laws say things like, "If you do an experiment here, vs. over there, you'll get the same answer". That's a Law. Exactly what the experiment might turn up with would be modelled by a theory, which might be, to a lesser or a greater extent, a bit wrong. The Law part though, is not the same thing. It's those Laws that the EM drive breaks. They're called Laws for a reason.
Scientific laws are simply iteratively improved models of an unknown reality
No. Scientific theories are. Laws, like that one about the conservation of energy, aren't. They say that the time derivative of the energy in a closed system is zero. They don't say it's close to zero, or nearly zero. They say it's exactly zero always, no matter that. It's not a theory. It's a law. That's why they say "The Theory of General Relativity", vs. "The Law of the Conservation of Energy". They're not the same thing.
It's the same thing with the conservation of momentum. You can't move without throwing something out the back of the ship. Sorry.
Please enlighten us on the "BASIC LAWS OF PHYSICS"
Happy to. The translational invariance of the physical laws, whatever those laws actually happen to be isn't important. Just that the same laws apply everywhere in space. From there, a very clever lady called Emmy Noether, who deserves to be much better known, proved (as in, mathematically. So no arguments are possible here. Or at least, if they are, we're in deep shit) the law (a word that is not used lightly) of the conservation of momentum.
I would argue that Newtonian physics was considered "proven" until more accurate measurements proved that our understanding was incomplete
I don't think that any scientist would have considered those theories "proven". No-one would consider GR to be "proven" either. It sure seems to work pretty well, but it's not proven, and it probably can't be. Symmetry, on the other hand, and the conservation laws by mathematical consequence, are not in the same category. They are much more basic, much more fundamental. As far as I can tell from the enormous quantity of wittering going on in this thread, no-one seems to realise this.
But the cold fusion fiasco didn't violate basic laws of physics. It just didn't actually work. The EM drive claims thrust without reaction mass. It's not even close to the same ballpark. It's not even the same game.
Maths is facts. The symmetry of the physical laws is as close to a fact as I think you can reasonably get. And I'm afraid that you're stuck with the conservation laws if you'd prefer to keep both of those facts.
The trouble with your argument is that you don't understand which laws this thing violates (forgive me if you actually do... ). Everyone is wittering on about the conservation of energy, but that's just ignorance. It's not a perpetual motion device, it's a thrust-without-reaction-mass device. That guy with the binary username isn't doing a good job of explaining that, but that's what is claimed. You get to generate thrust without having to carry fuel.
Now, a very clever lady, whom few have heard of, and whom I mentioned several times already, but this is a long thread and I think that this is very important, proved (using Maths, and we're still happy with 'Maths', being right, right?) that if you would like your physical laws to retain their symmetry then you're stuck with this conservation law. Look up Emmy Noether. It's very interesting stuff.
not just dismiss it out of hand because "These hoaxes come and go and people waste time on them"
But that's not completely true. We stopped looking at so-called 'perpetual motion machines' for this very reason. You know why? Because they violate the conservation of energy. Conservation of momentum has the same status. This really seems like alot of fuss over nothing to me.
There's a thing called conservation of momentum. If you generate thrust, without throwing an equivalent amount of stuff in the opposite direction, then you have violated that law. All propulsion systems ever invented, of any form, work on this principal. You have some mass, and you throw it out of the back of the ship. The total momentum of the system has to remain the same, and you normally can't carry much reaction mass (this is your 'fuel') with you, so you have to chuck that stuff out the back really fast.. This is fairly basic physics. It is a bit of a travesty that the brilliant mathematician Emmy Noether, who's laws link this principal with the symmetry of the physical laws, isn't more well known - but that's an argument for a different day.
So, if this device generates thrust, without chucking stuff out the back (photons count here, of course), then someone's going to have alot of explaining to do.
It will change the game in terms of transportation technologies with regards to space travel.
More than that, really, since if we're violating the conservation of momentum, then we've broken one of the forms of symmetry of the physical laws, the one that says that the laws of physics apply equally everywhere in space. That would be a much bigger deal than just revolutionising transport (which it might not do anyway, if the amount of energy required to perform this particular trick is very very large).
The first approximation we make is that the particle is moving at velocity near zero,
Which is fine, but right there you made an approximation, and ignored certain terms because they got really really small. Nothing wrong with that, it's perfectly sound engineering, but it doesn't change the fact that Newton's laws are wrong. Only a tiny tiny bit wrong, sure. Such a small amount of wrong that you'd only notice if you looked so hard that the measurement might even be impossible. But still, if we're going to be pedantic, which I think we should be, since this is fundamentally a fairly pedantic argument, Newton's laws are wrong.
Also, sorry to reply twice, but Newtons' gravitational laws are always wrong. It's just that they're normally wrong by a very small amount. That doesn't change the fact that they are, basically, not correct.
Slashdot Mirror
Solar sails are not in violation of the conservation of momentum, you don't have to carry the reaction mass though, you have the sun throw it at you instead. So if fuel is defined as stuff you gotta keep in tanks on board, then solar sails are indeed thrust-without-fuel.
However, if we would like our physical universe to behave the same no matter where you are - the translational symmetry of the physical universe - then you're stuck with the conservation of momentum. It really looks much more fundamental than any of our fiddling around with quantum electrodynamics, for example. Even if that does enjoy the auspicious acronym of QED. The claim is that this thing accelerates itself without any reaction mass of any kind, which is, simply put, not actually possible. That, with the addition that the effect is borderline unmeasurable, makes the whole think look very very much like, if not a hoax, then at least an elaborate error.
That's a pretty fair point. Let's split the difference and agree that they're both wrong.
In that case, I agree somewhat. Carl Sagan wrote a great book about space exploration, called Pale Blue Dot. It is by turns optimistic, and hopeless. You could build such a ship, but it's not clear that we could sustain human life in the vacuum (and hard radiation) of space for the thousands of years that it would take to make the trip. There's a nice science fiction story by Brian Aldiss that's sorta about the same thing - called "Non Stop". I'm not sure civilisation on board that ship would survive the trip, even if the ship itself did.
Sorry for replying out of context. I'd just watched The Neon Demon, I was a bit out of sorts :).
Binary man is actually right, though. You don't get to violate the conservation of momentum, because then you have a free energy machine. He may be a bit of a dick, but he is right.
I hope you're having fun, but you're not really doing anything to help people's understanding....
That's because you don't know what the physical laws are. I've been spending a (somewhat) fun evening writing all about it in this thread.
Poor 1101010101, or whatever his (or her) name is. He (or she) means Laws, not Theories. The Laws are immutable, the theories are a bunch of math that seems to work alot of the time.
The Laws say things like, "If you do an experiment here, vs. over there, you'll get the same answer". That's a Law. Exactly what the experiment might turn up with would be modelled by a theory, which might be, to a lesser or a greater extent, a bit wrong. The Law part though, is not the same thing. It's those Laws that the EM drive breaks. They're called Laws for a reason.
I shan't opine regarding the orthodoxy/crank argument in this thread, I'm just here to be pedantic about the history of physics.
You're welcome here anytime :).
Or, possibly, he knows his physics better than you do.
I'm loving this thread. It just gives and gives.
Scientific laws are simply iteratively improved models of an unknown reality
No. Scientific theories are. Laws, like that one about the conservation of energy, aren't. They say that the time derivative of the energy in a closed system is zero. They don't say it's close to zero, or nearly zero. They say it's exactly zero always, no matter that. It's not a theory. It's a law. That's why they say "The Theory of General Relativity", vs. "The Law of the Conservation of Energy". They're not the same thing.
It's the same thing with the conservation of momentum. You can't move without throwing something out the back of the ship. Sorry.
Please enlighten us on the "BASIC LAWS OF PHYSICS"
Happy to. The translational invariance of the physical laws, whatever those laws actually happen to be isn't important. Just that the same laws apply everywhere in space. From there, a very clever lady called Emmy Noether, who deserves to be much better known, proved (as in, mathematically. So no arguments are possible here. Or at least, if they are, we're in deep shit) the law (a word that is not used lightly) of the conservation of momentum.
I would argue that Newtonian physics was considered "proven" until more accurate measurements proved that our understanding was incomplete
I don't think that any scientist would have considered those theories "proven". No-one would consider GR to be "proven" either. It sure seems to work pretty well, but it's not proven, and it probably can't be. Symmetry, on the other hand, and the conservation laws by mathematical consequence, are not in the same category. They are much more basic, much more fundamental. As far as I can tell from the enormous quantity of wittering going on in this thread, no-one seems to realise this.
But the cold fusion fiasco didn't violate basic laws of physics. It just didn't actually work. The EM drive claims thrust without reaction mass. It's not even close to the same ballpark. It's not even the same game.
it utterly violated BASIC SCIENCE.
How did it? Serious question. What basic science did it violate?
Maths is facts. The symmetry of the physical laws is as close to a fact as I think you can reasonably get. And I'm afraid that you're stuck with the conservation laws if you'd prefer to keep both of those facts.
And if you told them that you could float magnets on top of such a superconductor, they'd have hauled you off to a sanitarium.
Not if you showed them. This EM drive isn't showing anyone anything. If it was, we wouldn't be having this conversation.
The trouble with your argument is that you don't understand which laws this thing violates (forgive me if you actually do... ). Everyone is wittering on about the conservation of energy, but that's just ignorance. It's not a perpetual motion device, it's a thrust-without-reaction-mass device. That guy with the binary username isn't doing a good job of explaining that, but that's what is claimed. You get to generate thrust without having to carry fuel.
Now, a very clever lady, whom few have heard of, and whom I mentioned several times already, but this is a long thread and I think that this is very important, proved (using Maths, and we're still happy with 'Maths', being right, right?) that if you would like your physical laws to retain their symmetry then you're stuck with this conservation law. Look up Emmy Noether. It's very interesting stuff.
not just dismiss it out of hand because "These hoaxes come and go and people waste time on them"
But that's not completely true. We stopped looking at so-called 'perpetual motion machines' for this very reason. You know why? Because they violate the conservation of energy. Conservation of momentum has the same status. This really seems like alot of fuss over nothing to me.
Impulse power Mr Cuthulu!
Gold.
Yet more science fiction becoming the real world.
There's a thing called conservation of momentum. If you generate thrust, without throwing an equivalent amount of stuff in the opposite direction, then you have violated that law. All propulsion systems ever invented, of any form, work on this principal. You have some mass, and you throw it out of the back of the ship. The total momentum of the system has to remain the same, and you normally can't carry much reaction mass (this is your 'fuel') with you, so you have to chuck that stuff out the back really fast.. This is fairly basic physics. It is a bit of a travesty that the brilliant mathematician Emmy Noether, who's laws link this principal with the symmetry of the physical laws, isn't more well known - but that's an argument for a different day.
So, if this device generates thrust, without chucking stuff out the back (photons count here, of course), then someone's going to have alot of explaining to do.
science fiction is science in it's larval stage.
Good heavens. No it isn't. Sometimes science fiction is a bit right - 99% of the time though, it's total hogwash. Larval Stage. Pah!
It will change the game in terms of transportation technologies with regards to space travel.
More than that, really, since if we're violating the conservation of momentum, then we've broken one of the forms of symmetry of the physical laws, the one that says that the laws of physics apply equally everywhere in space. That would be a much bigger deal than just revolutionising transport (which it might not do anyway, if the amount of energy required to perform this particular trick is very very large).
The first approximation we make is that the particle is moving at velocity near zero,
Which is fine, but right there you made an approximation, and ignored certain terms because they got really really small. Nothing wrong with that, it's perfectly sound engineering, but it doesn't change the fact that Newton's laws are wrong. Only a tiny tiny bit wrong, sure. Such a small amount of wrong that you'd only notice if you looked so hard that the measurement might even be impossible. But still, if we're going to be pedantic, which I think we should be, since this is fundamentally a fairly pedantic argument, Newton's laws are wrong.
Also, sorry to reply twice, but Newtons' gravitational laws are always wrong. It's just that they're normally wrong by a very small amount. That doesn't change the fact that they are, basically, not correct.