Wow. My gut tells me something is wrong here, and that this is being mismeasured. However, this would be an <i>enormous</i> breakthrough if it pans out, even at the low levels NASA has seemingly confirmed.<p>We're very good at generating power in space; solar is basically infinite in the inner parts of our solar system, and we have a lot of experience with RTGs and other power generation mechanisms. If we can directly turn power into thrust without burning fuel in the process, this truly changes everything.<p>But as I said, I think this will end up not panning out for one of these reasons: 1) The microwaves bouncing around cause a small amount of material to be lost and be sent out of the device, causing the thrust. 2) The RF in play is throwing off detection (this, to me, seems most likely -- it could explain the thousandfold difference in detected thrust levels between the Chinese and US tests). 3) Some sort of effect that is linked to gravity. No idea what, though.<p>I really look forward to further testing.<p>Edit: Given that I'm terrible with the scale of small numbers, I decided to do some quick math. If you were to use that thrust of 50 micronewtons to drive the Voyager spacecraft (722kg) full out for one year from a starting velocity of 0m/s, you would end up at 0.0911259m/s at the end of the year. By comparison, Voyager is currently traveling at 17km/s.
So, it seems from reading the paper's abstract that they did measure thrust <i>both</i> from the real propulsion test device and from the dummy test device. That's not very promising:<p><a href="http://ntrs.nasa.gov/search.jsp?R=20140006052" rel="nofollow">http://ntrs.nasa.gov/search.jsp?R=20140006052</a><p>> Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article).
Third replication then?<p>This stuff has been hovering (pun intended) at the edge of detection for some time: spinning superconductors, this thing, etc. all claiming to provide evidence of tiny amounts of thrust in apparent violation of standard conservation of momentum. Obviously skepticism is in order, but either something is very wrong with all these experiments or there's something here.<p>What's interesting about this one is that the original inventor has something resembling a theory. It may not be a complete theory, but it tries to explain it via relativity in a way that makes physical sense.<p>I'm always really skeptical of these things, but not in the knee-jerk total dismissal sense. I just say show me the replications. They're doing the right thing. Now we need more people to build these and test them under different conditions.<p>The ultimate test would be to launch one, since you can't really screw up detection of a big delta-V change in space.
This is one of these things which is just a few percent less crazy than it sounds.<p>The issue is that special relativity isn't quite compatible with quantum gravity, see<p><a href="http://en.wikipedia.org/wiki/Doubly_special_relativity" rel="nofollow">http://en.wikipedia.org/wiki/Doubly_special_relativity</a><p>What it comes down to is that quantum gravity has a length scale and a time scale, both of which are unthinkably tiny. However, special relativity says there is nothing special about any particular space or time interval because if somebody was going fast enough, an interval that looks like a planck interval to most people could get expanded or shrunk to something big like a kilometer or an hour.<p>But following that line of reasoning is problematic if there is no special reference frame, since for all I know I already am going incredibly fast relative to some imaginary observer.<p>Doubly-special relativity manages to preserve the invariance of the speed of light under ordinary conditions but also preserve the invariance of plankian quantities under extreme conditions. Related theories also bring in the idea of a special reference frame which means you might be able to "push" against the vacuum.<p>The main trouble jiving that with these experiments is that the energy scale at which DSS effects come into play is huge, way out in grand unification country, so it's hard to believe it could be probed by these experiments.
I've always thought it was unfair that this is impossible. It's not like you're getting something for nothing - you are still required to expend energy. So why does the universe have to be such a dick about converting electricity directly into motion?
For all those saying this is impossible because of X, I think the great Richard Feynman put it best:<p>"If it disagrees with experiment, it's wrong"<p><a href="https://www.youtube.com/watch?v=OL6-x0modwY" rel="nofollow">https://www.youtube.com/watch?v=OL6-x0modwY</a>
Previous discussion, from six years ago: <a href="https://news.ycombinator.com/item?id=314297" rel="nofollow">https://news.ycombinator.com/item?id=314297</a><p>Some interesting comments, and much skepticism
So it produced 720 mN of thrust the first try, but under more careful conditions it produced 30 uN? This smells like a spurious result, but I suppose more investigation is in order.
Wanted to jump in and ask, does anyone remember a site that went through the math of two magnetic rings being charged and discharged out of sync, utilizing the delay in the speed of light between the rings to create a net force? Imagine a craft shaped like a dumbbell, with the rings where the weights are:<p>|---|<p>1...2<p>The idea was that you'd create a strong magnetic field in ring 1, and then the wave would travel outward both directions (one away from the ship, and one along it) and interact with ring 2, which has the opposite polarity. Ring 2 would be attracted to the magnetism from ring 1, and pull the ship to the left. Then ring 1 would turn off, and by the time the wave from ring 2 reached it, there would be no interaction. So the craft would feel a net thrust to the left. The process would repeat over and over again at high frequency, propelling the craft faster and faster.<p>I believe the site said the process was 25% efficient, and didn’t violate any laws of physics. The difficulty lies with hysteresis because it takes a comparatively long time to charge a magnetic field, compared to the time it takes light to span the distance. So it went off on a tangent about using lasers to charge a superconducting ring.<p>But I’ve always wondered if resonance could somehow be used to take the coils out of sync automatically, a bit like a tesla coil but with an imbalance the puts one ring slightly behind the other in time with respect to their frames of reference. As they move more out of phase, the net force on the coils should get stronger and stronger. This sounds similar in some ways to the the way a magnetron works, so if it can be put out of phase in a similar way, then I’m not entirely surprised by NASA’s result. If it’s true that the time delay in the speed of light can be converted to a propulsive force, then it’s going to change, well, pretty much everything about space travel. I really wish I had the link to that site.
"...therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma..."<p>This could be extremely big news, like the biggest news of the last 50 years. Depends on whether it's true -- and how much it can be optimized. Field propulsion is a game-changer in humanity's relationship to the universe.<p>Lots remain to be seen, though. Wait-and-see is the appropriate response.<p>Still pretty neat. And it sounds like something that could easily be reproduced in college-level labs worldwide.
There's no mystery to producing thrust with microwaves. Photons have a momentum of E/c, so if you make photons with a power P and send them in one direction, you'll get a thrust of P/c.<p>I think the issue is that they claim to a) not emit anything, and b) claim many orders of magnitude more thrust than could be achieved by just emitting photons.
The top comment (on the actual article) suggests that the effect may be a result of dark matter resonance:<p><a href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.231801" rel="nofollow">http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111...</a><p>Which is way over my head, but interesting.
Is anyone reminded of <a href="http://www.bibliotecapleyades.net/tesla/occultether/occultether.htm" rel="nofollow">http://www.bibliotecapleyades.net/tesla/occultether/occultet...</a>? Which is complete pseudoscience but...
Is this the stuff Miklos Borbas was working on?
<a href="https://www.youtube.com/watch?v=RbOc6R-95kk" rel="nofollow">https://www.youtube.com/watch?v=RbOc6R-95kk</a>
It's logical when you think about it. Since particles pop in and out of existence all the time and the time these particles exist are > 0, then it should be possible to move those particles before they disappear. So law of conservation of momentum is not violated, neither any other law of physics. It is just counter intuitive, like most stuff related to quantum world.