EM Drive

[Skipjack]

Looks like the EM-drive is a bust. Too bad, but was to be expected
http://forum.nasaspaceflight.com/index. ... msg1526856

[GPecchia]

SeeShells might disagree. For all we know, China had great results and wants to throw us off the path. I'm still awaiting the report from the NASA experiments.
http://forum.nasaspaceflight.com/index. ... msg1526982

[Skipjack]

SeeShells might disagree. For all we know, China had great results and wants to throw us off the path. I'm still awaiting the report from the NASA experiments.
http://forum.nasaspaceflight.com/index. ... msg1526982

Well that would be strange since Yang's original report of exceptionally high thrust was what got this whole thing started in the first place.

[Carl White]

Rather pitiful though how triumphant they're all sounding that we're stuck with hugely expensive, explosion-prone rockets as the only way off Earth for the foreseeable future.

[Skipjack]

Rather pitiful though how triumphant they're all sounding that we're stuck with hugely expensive, explosion-prone rockets as the only way off Earth for the foreseeable future.

I see no reason to be happy about it. I am not surprised by the news, though. There is still some small hope, but I would not get it up too high.

[JoeP]

Rather pitiful though how triumphant they're all sounding that we're stuck with hugely expensive, explosion-prone rockets as the only way off Earth for the foreseeable future.

Same thoughts here when reading that!

[ScottL]

Rather pitiful though how triumphant they're all sounding that we're stuck with hugely expensive, explosion-prone rockets as the only way off Earth for the foreseeable future.

Science cares not for what we desire to be true, it deals only in actual truth. Nobody is feeling happy or triumphant that we are stuck, but that our understanding still holds true. If we do find a way to explore the stars, I'm willing to bet it is done via clever use of existing theory and not in some claimed flaw in our understanding of fundamentals.

[TDPerk]

It is past time for Dr. Woodward's work to see rigorous attempts at replication.

I believe the phrase used was, "6 sigma" data.

[williatw]

If we do find a way to explore the stars, I'm willing to bet it is done via clever use of existing theory and not in some claimed flaw in our understanding of fundamentals.

Afraid I don't agree. I remember a few decades back how cosmologists were saying that in a few years we would be able to do an accurate census of the Cosmos and know whether the Universe contained enough matter to brake the expansion of the big bang to a stop, and cause a collapse, or expand forever. Then we discovered that the Universe was not only going to expand forever but that it was accelerating; by some unknown agent commonly referred to as "dark energy", making up the bulk of Creation. "Dark Energy" ~70% of creation, really just a term used to describe an effect (the accelerating expansion) of empty space itself not just the increasing distances between galaxies; the true nature/cause of which we know practically nothing. Matter/energy as we understand only being about 4%; with the balance being "Dark Matter", another term used to describe an effect (gravitational lensing etc.) about which we know slightly more than we do about dark energy. This doesn't really jibe with the idea that we can confidently assert that there are no "claimed flaw in our understanding of fundamentals". I would say our fundamental ignorance of the way things really are leaves more than enough room for some kind of mysterious EM Drive to be possible (or maybe even Sonny White's warp drive); to say nothing of other things yet to be discovered.

[ladajo]

While your argument is sound, I would offer to remember that it is based in 'what we perceive'. The way you express yourself tends to paint you in a somewhat positivist ontology. A more constructivist perspective might provide that while we make sense of what we see, there are things we don't, as these once uncovered, may change how we see things now.
Probably one of the more entertaining explorations in this can be found in the speed of sound explorations and understandings. Especially regarding the what would happen to an object/organism that exceeded it.
Bottom line, we see evidence of what you say, however it should be tempered with the knowledge of unknown unknowns.

[williatw]

Probably one of the more entertaining explorations in this can be found in the speed of sound explorations and understandings. Especially regarding the what would happen to an object/organism that exceeded it.

It will experience "Sonic boom"? I will assume you meant speed of light explorations. My understanding is that Sonny White's warp drive if it works wouldn't technically violate Relativities' speed of light upper limit. That is the ship doesn't actually move faster than light, space is contracted in front of the vessel and expanded behind it. The ship might appear to be rushing off at some insane rate of acceleration/velocity; but really isn't. Kind of like UFO's are allegedly observed to move. It is space itself which would be contracted/expanded at superluminal velocities & that doesn't violate relativity. After all the universe itself is believed to have expanded (early hyper-inflation) at superluminal velocity. The only way the Universe can continue to expand at an accelerating speed (and I don't think that even the rate of acceleration is constant but is increasing?) is that somehow new energy is pouring in from somewhere else. It only appears as if the Universe is a closed system looking at the mass/energy (the 4%) that we can detect and measure. The quantum vacuum then must be awash with energy; maybe the EM drive if it works is somehow interacting with that; it only appears to be violating conservation of momentum and /or energy because we can't properly measure this interaction?

[ladajo]

No, I meant speed of sound.
There was some interesting thinking going on about what would happen to something that exceeded it before we understood what it really meant.

[ScottL]

White's theory relies on pushing on or off of virtual particles and virtual particles are a mathematical representation similar to the use of imaginary numbers, so I wouldn't hold my breath on his theory. What you are describing is not White's theory at all, but a thought experiment by Alcubierre which said it's possible if you can produce massive amounts of negative mass. What White did was show that the math could be done in such a way as to reduce that mass amount of negative mass to a "more reasonable amount of negative mass" via geometry. Unfortunately, this is a thought experiment and to-date we have no knowledge on how to generate negative mass, unless that is you buy into Woodward's theory. Only Woodward claims to be able to do this via the oscillation of a dielectric capacitor, but is not really related to White's theory (pushing on virtual particles).

Negative mass isn't disproven per se. We simply have no way within our current realm of knowledge to produce it. There is, to my knowledge, no known reason it couldn't be done. By formulating a theory and providing a mechanism for producing said negative mass would be in the realm of a clever use of fundamental physics with an as mentioned before unknown unknown. It wouldn't shake our understanding at all, but enrich it further.

[ladajo]

We simply have no way within our current realm of knowledge to produce it.

And my point extends this to include "or know it if we did."

[DeltaV]

Possibly of interest for some of the EMdrive hypotheses being discussed at NSF.

I'd post these there if I had an account, maybe someone both here and on NSF can link.
(May have found one or more of these on NSF, don't recall... apologies if any repeats.)

On Divergence in Radiation Fields
http://arxiv.org/pdf/1605.00327v1

Absorption by Non-Radiating Systems
http://ece-events.unm.edu/amerem2014/Re ... TS/071.pdf

Stored energies for electric and magnetic current densities
http://arxiv.org/pdf/1604.08572v1

Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk
http://arxiv.org/pdf/0707.1216

On electromagnetic induction
http://arxiv.org/pdf/physics/0008006v1