Slashdot Mirror
Leaked NASA Paper Suggests The 'Impossible' EM Drive Really Does Work (sciencealert.com)
A source close to NASA Eagleworks has leaked the test results of the 'impossible' EM Drive. While it's important to note that the results that have been leaked haven't been published in an academic journal, they do suggest that the system works and is capable of generating force of 1.2 millinewtons per kilowatt in a vacuum. ScienceAlert reports: The paper concludes that, after error measurements have been accounted for, the EM Drive generates force of 1.2 millinewtons per kilowatt in a vacuum. That's not an insignificant amount -- to put it into perspective, the super-powerful Hall thruster generates force of 60 millinewtons per kilowatt, an order of magnitude more than the EM Drive. But the Hall thruster uses fuel and requires a spacecraft to carry heavy propellants, and that extra weight could offset the higher thrust, the NASA Eagleworks team conclude in the paper. Light sails on the other hand, which are currently the most popular form of zero-propellant propulsion, use beams of sunlight to propel them forward rather than fuel. And they only generate force up to 6.67 micronewtons per kilowatt - two orders of magnitude less than NASA's EM Drive, says the paper. The NASA Eagleworks team measured the EM Drive's force using a low thrust pendulum at the Johnson Space Centre, and the tests were performed at 40, 60, and 80 watts. They were looking for any sign that the thrust could be a result of another anomaly in the system, but for now, that doesn't appear to be the case. "The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified," the team, led by Harold White, concluded in the paper. "Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 millinewtons per kilowatt." But the team does acknowledge that more research is needed to eliminate the possibility that thermal expansion could be somehow skewing the results. They also make it clear that this testing wasn't designed to optimize the thrust of the EM Drive, but simply to test whether it worked, so further tweaking could make the propulsion system more efficient and powerful.
I need to see more than this article to convince me this works.
This is literally what it is, specifically it's acceleration that is being rounded up.
It'd make an excellent engine for anything that gets lifted into space and is supposed to stay there for a long time, such as satellites...
I'm no physicist myself, and physicists don't understand this thing anyway, but here's my understanding:
Yes, appears that the only input is electricity, and it seems to produce thrust. So if electricity is free, a tiny amount of thrust is free. I say it APPEARS that the only input is electricity- many reactions which we now understand include oxygen from ambient air as an input, and that might have easily go unnoticed in an experiment before the reaction was understood. Similarly, it's possible that this thruster is using some non-obvious input, such as ambient radiation.
We don't know if one could be built much larger, or what the current capacity is for a given size. Maybe a 100,000 watt one could be small, maybe it would need to be very large. Maybe it would be far more efficient, maybe far less. We're still trying to confirm that the thing works at all.
> would I be right in thinking this thing would incredibly slowly start moving the ship and over a ridiculous amount of time, eventually be moving very rapidly and in theory (?) just keep on accelerating?
Yes, in theory, up to near the speed of light. Or maybe not. 1500 years ago someone discovered that if you burned charcoal mixed with livestock poop in a bamboo shoot, you got a similarly weak thrust. Later we figured out it was the dried pee, not the poop, that mattered and adding sulfur helped. So a thousand years ago they had black powder rockets, which kept accelerating through the air as long as the engine kept burning. Now we know that a rocket won't keep accelerating forever in air, but it took a thousand years to figure that out. We're still in the "poop in a tube" stage of EM drives, so we really don't know what the potential is.
First rule of science: Science doesn't settle
No, it really does. Conservation of momentum is a principle very deeply baked into physics and has had a vast amount of testing. It's reached the point where anyone claiming otherwise is quire reasonably considered a crackpot unless they have some quite amazingly compelling evidence.
When science is settled you need more than a brain fart to overturn it.
SJW n. One who posts facts.
This is ridiculous. Conservation of momentum is valid in both quantum field theory and general relativity, there are an appropriate versions of Noether's theorem for them. And I don't see why are you harking about the Casimir effect: it doesn't violate conservation of momentum either.
Your suggestion that conservation of momentum might fail because of some fundamental discretization of space is also insane: first of all this is just speculative physics at this stage. Second, everyone that does speculate about it agrees that to probe the existence of this discretization would require particle collisions with energy around the Planck energy, about 10^28 eV. For comparison, the maximum we can do now, in the LHC, is to collide particles with energy of 10^13 eV.
To think that some lame tabletop experiment using only classical electrodynamics, running at most at 80 watts, somehow magically found a way to probe phenomena from an energy scale 15 orders of magnitude larger than the LHC scale, just shows a complete lack of knowledge of all the science involved. At the very least, it would show that the whole particle physics community are complete idiots for spending billions of euros in the LHC, while even more revolutionary science could by done on spare change by Eagleworks.
entropy happens
Logic and math can't prove anything is true in the ultimate sense. All math is built on unprovable assumptions called "axioms". Logic cannot prove truth, only consistency, or contradiction. That's why science has to complement math and logic with actual observations.
"It provides a constant force for a constant power, [..]"
Has this been tested? No. That is an assumption. If the nature of the effect is not understood, then such an assumption may well be wrong, along with your conclusion.
Refusing to analyse this phenomenon properly because of unproven conflict with an established law of physics strikes me as very un-scientific approach. Something best left to high school physics 101 classes, at best. A scientists seeks to understand thoroughly and does not dismiss the idea by hand waving in the general direction of established laws of physics. The science does NOT settle, the science always assumes there is a potential for fundamental mistakes in the current understanding of the universe, including the most basic rules.
Separating graphite layers does not contradict our basic understanding of physics. I don't have any problem with doing it with scotch tape. Ditto for hunting axions: it is an extension of known theories, not a breakdown of our fundamental theories (that is speculated to happen at high energies). But even hunting axions is already much harder than building this stupid EM drive: they had to make a very specialized very sensitive apparatus, for the simple reason that if axions were easy to detect they would have already been detected.
Large Extra Dimensions, on the other hand, is another story: there is no half-way decent theoretical model that predicts them, they are just pure speculation. And they were predict to show up at the LHC scale, with the prediction now changed to just above LHC scale, since they did not show up. And doing that is free, since there is no model to build, you just need to throw some numbers in the air.
Contrast this with fundamental discretization, which is expected to happen for good theoretical reasons, and there are actually some speculative theories (string theory and loop quantum gravity) that implement it.
entropy happens
Not quite. A bit of cart-before-horse.
Once there's enough testing done to prove it has potential, then engineers will take it, play with it, improve it, apply it, then sometime later, physicists and other scientists will figure out precisely why it works and why what the engineers did worked.
Strat
Progressivism (aka US 'Liberalism'): Ideas so good they need a police/surveillance-state to enforce.
Well, laws of physics are created by humans to understand and explain how things work, they are far from absolute (yes some scientists really believe they are absolute, dumbass scientists that is).
The laws of physics are absolute even if we don't know exactly what they are yet. If they're not then you're essentially saying that anything can happen at any time for any reason, i.e. magic exists.
There are still so many mysteries that cannot be exlpained using the 'laws of physics' as they are now, so even in that regard you know these 'laws' are not definite..
That's just flat-out mysticism.
SJW n. One who posts facts.
This paper does not show new physics. It shows a combination of experimental error and wishful thinking.
entropy happens