Yes, we have a very good working theory of the *manner* in which gravity bends spacetime. But we can't answer even the most basic question about its *method* - why does mass bend spacetime? Or have we found some clues when I wasn't watching?

Isn't it one of the basic assumptions of modern cosmology there's no particular reason to assume "empty" space is currently in the lowest possible energy state? I believe one of the respected "Big Bang" theories involves a point in the false vacuum spontaneously decaying to a lower energy state, setting off a chain reaction that raced (actually, still is racing) across the universe at almost the speed of light, spawning modern mass-energy in its wake. And one of the unnerving takeaways was that we have absolutely no idea whether we're at the lowest possible energy state now, or if that could happen again. We may look up one evening and discover that the night sky is beginning to glow, as the wave front of a new chain reaction enters the visible universe.

But I have to say I don't see that your other objections follow. How does empty space having some as yet undefined sort of "traction" to it (the only thing a working drive would directly imply, competing theories aside) imply that it's in a non-minimal energy state? And how would either imply that you could extract energy from it? It would seem to me that so long as the drive consumed at least as much energy as it imparted as kinetic/potential energy then there's no net energy extraction: rather we're dumping energy "somewhere" to get local momentum. Perhaps calling for a unification of the Laws of conservation of momentum and mass-energy.

Or are you directly addressing the warp drive theory? I admit I haven't actually looked at the details yet.

>Here they could have the key to warping space/time, and the first use is to putter along in orbit cheaply.

Seems beautifully appropriate to me. I love a technology that scales gracefully, and at this moment in or development cheap maneuvering around the solar system would unlock whole new worlds of potential, especially if it can be used to climb into orbit. Plenty of time for warp drives after we figure out how to live in space.

Or do I know enough of mob psychology to draw some unflattering parallels with how democracy works in practice?

Hmm, tough call... I'll say 2.718 Telemundos.
New interactions would probably imply either new forces, or new properties of the particle - and either would pretty much require rebuilding the theories upon which particle physics is based.

Of course we're also departing from the fact that there's presumably nothing but microwave photons, virtual particles and passing neutrinos within the thruster's resonating chamber. The photons can't escape, and wouldn't provide more than a tiny fraction of the measured thrust even if they did. Available neutrinos probably don't offer anywhere near the reaction mass necessary even if they could be teased into interacting with the microwaves. That leaves the virtual particles, and I suppose the fabric of spacetime itself. So a poorly understood phenomena, and a complete unknown, prime candidates for discovering new physics weirdness!

So no: they're not being found innocent, so they're not exonerated. They simply have the charges dropped for lack of legal evidence. If someone can be bothered to get evidence legally (if any still exists) then the charges could be brought against them again. If they had been found innocent then, even if someone found a mountain of undeniable evidence against them the next day, they could no longer be charged with the crime thanks to the Fifth Amendment's double jeopardy protection.

I'm using corruption very much according to your definition - perhaps you read some other intent into my comment, in which case please re-read it with that in mind so we can have a more fruitful discussion. Or do you contest the assertion that our representatives at the national level are, by and large, comfortably in the pocket of corporate and other wealthy interests?

As for the best interest of the nation being debatable - you are absolutely correct. So long as we can agree that the foundational premise of democracy is that the power of government originates with the governed. And that thus the best interests of "The Nation" should always be synonymous with those of "The People", and any representatives deserving of the name needs to be ruling the nation for the benefit of the masses, hopefully with a watchful eye on long-term implicatons of today's decisions. At present though it certainly seems like the wealthy and powerful have largely co-opted the government to serve their own interests at our expense.

I have to disagree. Not with them being ordinary folks - that's true enough, and a good reminder that ALL of us have the potential to be heroes, if we only have the courage to do what's right, rather than what's convenient.

But that a democratic system would never do despicable things that it accuses the other side of? Many a mob would disagree, and a mob is probably the most democratic system that has ever existed. In fact even a very many individuals are prone to accusing others of their own failings - why would you assume we would become more virtuous en mass?

The problem is not "The System", though it has admittedly become twisted enough by institutionalized corruption that it would be difficult to fix. The problem is not even that pretty much since its inception it has been populated by the sort of people who want power - such is true of most any system that grants it.

The problem is that we, the populace, trusted "the system" to protect us from the inevitable corruption of the very people who run it. We abdicated our democratic responsibility to keep our government to heel. We embraced party politics, despite be warned of their dangers by the very people who created "the system". We vote for the people who run the flashiest ads appealing to our hopes, fears, and biases, rather than spending the time and energy to actually investigate the candidate's track records and put our support behind the ones who actually best represent our interests. There is no system that can protect us from the abuse of power so long as we continue to freely hand that power to those who wish to abuse it, and reward that abuse with reelection rather than retribution.

Is a heroic sacrifice to open an escape route from a burning building any less heroic because the people inside decided they'd rather roast marshmallows than flee?

Even if we here in the US refuse to organize to bring our government to heel, at least the truth of the rot has been exposed to the rest of the world, so there's some hope that nations whose population have not abandoned democratic responsibility can fight its spread into their own governments.

You've just described most of particles physics - most of the really interesting particles are so unstable on their own that they can only be detected by their byproducts. Quarks for example basically don't exist outside a proton or neutron -we know they're there by tracing the energy "fingerprints" of their nergetic interactions: To consistently get A and B from C and D, the intermediate components must have the following properties...

If it were pushing against some hitherto unknown particle, that would possibly be even MORE dramatic - we'd have a fundamentally new particle, and with it all new physics to explain how it can interact with normal matter / microwaves in such a way that it's only been detected in this very specific scenario, despite the fact that it must exist everywhere and be capable of passing through normal matter largely unimpeded. Even the "here there be dragons" of Dark Matter won't qualify- this appears to be interacting far to strongly with EM fields.

Granted, radiation shielding isn't particularly effective for vehicles, but it makes perfect sense for habitats. The ISS for example is basically just sitting there, we could instead maneuver a suitably large asteroid into position via the low-energy interplanetary transport network and start hollowing it out. It has a large up front cost in time and/or energy, and we'd probably want to put it in a higher orbit since its increased bulk would add air resistance(and it's unlikely to burn up on reentry if abandoned like the current tin cans), but other than that, job done.

It can also potentially make sense as cyclic transportation - for example there's the old concept of an Earth-Mars cycler: put an asteroid in a elliptical orbit that almost touches the orbits of both Earth and Mars and build a "cruise ship" inside it. Then you never accelerate it again, aside from station-keeping: instead you use normal spacecraft to transfer your payload between the cycler and Earth when they are in conjunction, and with Mars a year or whatever later when those two come into conjunction. Of course that's a seriously long-term investment for a relatively slow transportation system, but if there's a LOT of radiation-sensitive people/cargo making the trip and not in a hurry, then perhaps it makes sense.

How about the Casimir effect, where a pair of slightly separated parallel plates experiences an anomalous attractive force? There is some controversy, but I believe that's generally accepted as being the result of restricting the wavelengths of virtual particles that can form between the plates, and thus generating a net inward pressure on the apparatus due to the longer-wavelength particles that can only form and bounce off the outer surfaces of the plates. Granted, with both plates moving towards each other there is no net momentum transfer, but you still have a normal macroscopic apparatus directly interacting with the "quantum foam"

Well, to be fair you should say it *appears* to violate conservation of momentum. It's probably a fair bet that, assuming it does actually work, the universe is simply a bit more complicated that we thought. Whether it's pushing against virtual particles, asymmetrically distorting spacetime, or something else entirely, I would bet that there is in fact a momentum transfer occurring, but that we simply don't yet understand where it's being transferred *to*.

For example - if it's somehow pulling on the fabric of spacetime itself then it might not be unreasonable to consider that the entire rest of the universe is the reaction mass being pushed in the opposite direction. If it's pushing on virtual particles, then perhaps we misunderstand the ultimate nature of those particles and/or how they interact with spacetime. Perhaps they are "real" within a parallel universe, and we are transferring momentum to that universe. Or... I just heard of a new hypothesis making the rounds (if you'll excuse me doubtless butchering it badly) that quantum entanglement such as between a pair of virtual particles actually involves direct wormhole connections between the entangled particles - allowing them to remain in direct, distanceless contact even when one has crossed the event horizon of a black hole, thanks to the alternate path connecting them - which apparently resolves at least one set of QM/GR paradoxes. I admit I didn't understand the leap, but their suggestion seemed to be that the multitude of miniscule wormholes, taken collectively, actually constructs what we consider to be the normal fabric of spacetime. Related? Who knows, but it sure sounded interesting.

Yep. The catch of course is that "throwing the device into space" can easily cost millions of dollars, while the experiments thus far haven't been able to attract a fraction of that level of funding. So the march of science plods on, doing it's best to make enough incremental improvements in the effectiveness of the drive and confidence of the experimental integrity to justify the next round of more expensive experiments that will hopefully be conclusive enough to justify the next round of experiments... until eventually, hopefully, the results are conclusive enough to justify spending serious money on it.

Some folks like to mock scientists as always leaving their experiments inconclusive enough to justify further research, but in practice I think it's very rarely by choice - pretty much everyone I've ever met would rather do the properly conclusive experiment up front so that they can start focusing on applications (or get on with their lives) - but the people controlling the purse strings aren't going to part with the necessary money without having a high confidence of success, so instead it takes years of time and money "wasted" on incremental experiments whose only payoff is avoiding spending "conclusive experiment" money up front on a lot of dead ends. How many researchers have died of old age before the devices they designed in their youth have aver been properly tested?

Not having a sound theory to explain the phenomena is hardly a condemnation of the phenomena itself: see gravity - we've got essentially no idea how it works beyond "very well, thank you", but everybody trusts that it does. In fact a lot of major technologies have worked that way: We were making cheese, beer, etc. for thousands of years before we had any sort of microbial theory to explain the process. Gunpowder long before we had a sound theory of the chemistry involved. Etc.

Now the shoddy experiments on the other hand are an absolutely good reason to not take the initial results too seriously - but *good* experiments on something like this are expensive, so it's only natural that the preliminary experiments are shoddy - they're essentially the proof of concept used to justify the investment needed to perform better experiments. And that's exactly what we've been seeing: a progression through increasingly rigorous experiments which have, thus far, continued to confirm the phenomena. Now it's been tested in hard vacuum, ruling out the leading conventional explanations of ion drive and/or thermal convection effects. Assuming they again tested it in multiple alignments to rule out systemic flaws in the testing apparatus, it's beginning to look like there may really be a new phenomena present. Hopefully now someone will be able to get the funding to build a thruster powerful enough to be tested by NASAs more accurate and time-tested facilities.

And assuming they're still seeing the effects after a rigorous ground-based test, then probably someone will eventually be willing to invest the millions of dollars necessary to launch an EM-driven satellite to give it a real-world test. Though if the results are conclusive enough to spend that kind of money, it may well be that it then attracts more serious R&D dollars for further development on Earth until it's powerful enough to be useful.