SoylentNews is people
SoylentNews
from the that-still-doesn't-mean-it-will-work dept.
After months of speculation and leaked documents, NASA's long-awaited EM Drive paper has finally been peer-reviewed and published [open, DOI: 10.2514/1.B36120] [DX]. And it shows that the 'impossible' propulsion system really does appear to work. The NASA Eagleworks Laboratory team even put forward a hypothesis for how the EM Drive could produce thrust – something that seems impossible according to our current understanding of the laws of physics.
In case you've missed the hype, the EM Drive, or Electromagnetic Drive, is a propulsion system first proposed by British inventor Roger Shawyer back in 1999. Instead of using heavy, inefficient rocket fuel, it bounces microwaves back and forth inside a cone-shaped metal cavity to generate thrust. According to Shawyer's calculations, the EM Drive could be so efficient that it could power us to Mars in just 70 days.
takyon: Some have previously dismissed EmDrive as a photon rocket. This is addressed in the paper along with other possible sources of error:
The eighth [error:] photon rocket force, RF leakage from test article generating a net force due to photon emission. The performance of a photon rocket is several orders of magnitude lower than the observed thrust. Further, as noted in the above discussion on RF interaction, all leaking fields are managed closely to result in a high quality RF resonance system. This is not a viable source of the observed thrust.
[...] The 1.2 mN/kW performance parameter is over two orders of magnitude higher than other forms of "zero-propellant" propulsion, such as light sails, laser propulsion, and photon rockets having thrust-to-power levels in the 3.33–6.67 μN/kW (or 0.0033–0.0067 mN/kW) range.
Previously: NASA Validates "Impossible" Space Drive's Thrust
"Reactionless" Thruster Tested Again, This Time in a Vacuum
Explanation may be on the way for the "Impossible" EmDrive
Finnish Physicist Says EmDrive Device Does Have an Exhaust
EmDrive Peer-Reviewed Paper Coming in December; Theseus Planning a Cannae Thruster Cubesat
(Score: 4, Funny) by EvilSS on Tuesday November 22 2016, @03:28PM
(Score: 1, Funny) by Anonymous Coward on Tuesday November 22 2016, @04:11PM
Now excuse me, I need to go grab some popcorn.
Do you know what kind of science it takes to pop that popcorn? Of course you don't because science can't explain it! Popcorn Creationism for the win!
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:16PM
fuckin magnets how do they work
(Score: -1, Troll) by Anonymous Coward on Tuesday November 22 2016, @04:46PM
Take apart a vibrator to find out.
(Score: 2) by fritsd on Tuesday November 22 2016, @07:04PM
fuckin microwaves [wikipedia.org] how do they work, and what's the connection between popcorn and VASIMR?!?11?
(Score: -1, Troll) by Anonymous Coward on Tuesday November 22 2016, @07:17PM
Oily lube.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:22PM
Simple: Intelligent Attraction.
(Score: 2, Funny) by khallow on Tuesday November 22 2016, @06:31PM
(Score: 2) by DannyB on Tuesday November 22 2016, @04:43PM
Will this drive improve our understanding of physics? Or is the principle of its operation already well understood?
In an earlier millennium there was this thing called "The Edison Effect". Where somehow current could flow from the filament of a light bulb to a plate within the same glass bulb. This explained and confirmed some things. But it must have seemed quite spooky at the time.
The lower I set my standards the more accomplishments I have.
(Score: 2) by mcgrew on Tuesday November 22 2016, @05:56PM
But it must have seemed quite spooky at the time.
In 1926, Hugo Gernsback called electricity the mysterious fluid. [mcgrewbooks.com]
mcgrewbooks.com mcgrew.info nooze.org
(Score: 3, Interesting) by ledow on Tuesday November 22 2016, @08:09PM
Well, according to what I read, we know that the wave-particle dualities are there. Every schoolboy has done the double-slit experiment to prove that light acts like a wave, even if it acts like a particle elsewhere.
And we know that we don't yet have a conclusive interpretation of the quantum world, just a few good guesses.
But even back in the 20's when this stuff was in its infancy, fluid-modelled stuff was showing promise but then sidelined by other interpretations.
The paper's authors appear - but I can't say they are doing so impartially - to imply that such a thing could explain the extra force generated by... well... nothing. It's literally using waves in a vacuum (all vacuums have waves and energies and all kinds of stuff in them, just not classical particles) to get a small "bounce" off it - it's literally bouncing off empty space and gaining energy from a wave field that permeates all space, even vacuums. It's a little like surfing - the wave is there, going up and down, and normally you just bob up and down with it, but if you get the right conditions, you can use it as a form of propulsion. That's what they say is happening here... they are riding a wave that other quantum interpretations don't have or don't rely on to explain things.
And the background material linked has a classical-physics demo that appears convincing to my mathematician-but-hate-physics eye. Bounce a tray of fluid enough at the right rate and you can drop a drop of the same fluid into it and the drop will bounce forever, hitting the fluid and bouncing back up, staying separate the whole time, generating ripples in doing so, which become waves which help it bounce again the next time in a form of resonance. Do it right, and the drop will not only bounce forever, though, but - on a otherwise flat but vibrated surface - it will actually surf a little tiny wave in the underlying fluid with each bounce. There's some videos linked via the fluids discussion in the conclusion of the paper. The drop is going bounce-bounce-bounce up and down but a wavefront forms and gives it a tiny nudge in a direction.
If you track that "wandering" enough, you'll see that it confirms to a lot of the probabilities that quantum physics tries hard to explain. You can't guarantee where the particle will be but if you measure it long enough it conforms to quantum expectations, including peaks and troughs where you'd expect if the probability were higher/lower. Bouncing "walkers" interact like quantum particles. Steer them through double-slits and you see the same kind of phenomenon that we see with double-slit experiments. The waves break up, interfere, reinforce and cancel out, like a wave does, and that affects where the particle (the bouncing drop) could end up too. Get enough particles and probabilistically you see them act like waves, overall. It would seem - to an amateur - to marry quantum and classical worlds quite nicely. It's certainly an interpretation of quantum physics that I "prefer" as a mathematician, but I have no idea of the maths behind it.
It seems to be a theory undergoing some recent resurgence, but whether that's just bandwagons and opinion or fact isn't proven or disproven by this paper. It merely suggests it as a possible explanation, that isn't explained by other interpretations. It could be bunkum. But the underlying theory sounds plausible, the effect is measurable and unexplained, and nothing else comes close to telling you what could be happening. Everyone else basically says you shouldn't be able to get energy from a vacuum like they are provably doing.
All this proves, though, is that there's an effect in there that we can't really explain completely. Experimenting in a reproducible test is the best way to learn and discover, and it appears that we have a reproducible test to work with. That means, whatever happens, we're about to learn something about the universe. How important that is, whether it will completely blow out Copenhagen interpretations, etc. is unknown.
But - like me reading the paper and background citations - we will definitely learn something that we don't currently know.
(Score: 1) by Demena on Tuesday November 22 2016, @11:21PM
Ack! You 'believe' in Hawking radiation, right? Produced by one of a pair of particles from a black hole escaping? What happens to the other particle left behind the event horizon? Cue: Unruh radiation. Unruly was not what you would call an armchair physicist
(Score: 2) by ledow on Wednesday November 23 2016, @07:58AM
The Hawking radiation that nobody has ever observed, despite several missions designed to find it? Given that it was first proposed in 1970-something, that's quite a time to remain without any experimental evidence whatsoever.
To be honest, I'm not saying I don't. I'm saying that having an easy, imaginable method of how particles and quantum-level entities operate is much more useful and simpler tool, and simpler is often better.
And I'm not sure that either are somehow excluded by such effects anyway.
(Score: 1) by Demena on Wednesday November 23 2016, @08:39AM
That Hawking radiation has not been observed is a legitimate statement but it also applies to an electron. For both there is lots of evidence but neither is directly observable. Sure Hawking radiation is buried a little deeper but if it is not there we lose too many good explanations for too many things. But it is the other side of the coin, Unruh radiation, that I am intrigued by. If we find meta materials that can affect if or be affected by it then magic may happen. And there is an experiment or two that may be almost direct observations.
One of the beauties of MiHsC is that it is so simple and so much falls out of it. MiHsC predicts effects that that are observable and measurable. Many of them. It provides a simple model for inertia that explains the dynamics we observe throughout the universe on multiple scales more accurately than any dark matter/dark energy hypothesis. It also provides an explanation of the EM drive and provides formulae to calculate the thrust produced by different designs. It explains a lot of current anomalies really well.
http://physicsfromtheedge.blogspot.com.au/2014/01/mihsc-101.html [blogspot.com.au]
(Score: 1) by Demena on Tuesday November 22 2016, @11:13PM
Well it is not understood by it's discoverer (not inventor) but it is well explaned (predicted even) in MiHsC.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:48PM
I didn't know that the physics of armchairs is such a popular topic. :-)
(Score: 2) by bob_super on Tuesday November 22 2016, @06:03PM
If you're gonna spend a quarter or a third of your life sitting on something, you should get familiar with it.
An elder gentleman, when I was in college, pointed out that we spend more time holding a mouse, running our fingers on a keyboard, and staring at a screen than we do the same actions with our sex partners. And the lifespan of our relationships is often much longer with the former. Yet we usually don't dedicate anywhere near as much time or money picking them...
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:57PM
yeah. do you realize most people actually don't spend any time at all choosing their own children?
this is a person who will live with you for 20 years, you will have to provide for all their wants and needs, and deal with all of their problems, but you spend zero amount of time choosing between the different options. unless you adopt.
(Score: 2) by bob_super on Tuesday November 22 2016, @08:02PM
I'm also gonna spend a lot less time deciding the color of the asteroid that will obliterate civilization than I did choosing today's socks.
Thanks for false equivalences, but I don't live in a place where my spouse was chosen for me.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @01:33AM
"Yet we usually don't dedicate anywhere near as much time or money picking them..."
Men used to just marry a cute female child.
They didn't used to have to spend too much time picking which roastie whore would stab them in the back.