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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.
They are directly related. https://ntrs.nasa.gov/search.jsp?R=20110023492
I thought the science was settled on Newton's laws...
First rule of science: Science doesn't settle
Hanlon's Razor -- Never attribute to malice that which is adequately explained by stupidity.
You can't just "use the name" of any government agency unless you are properly affiliated, or the man will drop the hammer on you hard.
I thought the science was settled on Newton's laws...
Firstly, Newton's laws are based on observation and assumptions.
The observations gives us formulas that seem to fit, but there's no guarantee that those formulas describe all situations in the universe.
The assumptions, from Noether's theorem stating that symmetries imply conservation laws, are that the universe is smooth, in the mathematical sense of smooth being that space is infinitely divisible. We know that last part isn't true: you cannot measure position to an arbitrary precision in the universe.
It is therefore seen that Newton's laws become increasingly inaccurate when the scale is very large (relativity), or very small (quantum mechanics).
You might check out the Casimir effect some time.
It's not predicted by Newton's laws, but measurable and predictable using QM.
Anyone who says "EM drive cannot work because it violates my understanding of physics" should really check out the Casimir effect.
If your understanding of physics does not predict the Casimir effect, you probably shouldn't be commenting on the EM drive, or results from NASA rocket scientists.
They are directly related. https://ntrs.nasa.gov/search.j...
As the NASA document you cite (HTML FTW!) says, it's "an advanced propulsion physics laboratory, informally known as "Eagleworks"" being implemented by NASA Johnson Space Center (NASA/JSC), so it is part of NASA.
That's not why the EM drive is neat. The force provided by emitted radiation is a fairly well understood and predictable phenomenon. The EM drive has a sealed microwave cavity, so it doesn't emit many photons, and those that it does through thermal radiation are measured and accounted for. Despite that, the EM drive appears to produce an additional force, that is what makes it neat.
Yes photons have momentum and a photon drive would be 1kW / 0.00334 millinewtons.
The Eagleworks paper has already been accepted by the AIAA, which could fairly be described as "reputable". It will appear in the December 2016 issue.
Why would anyone engrave "Elbereth"?
Police Officer: "The light was red; you went through an intersection on a stop light"
Starship Officer: "It was green at the speed I was going"
Did you know that before he wrote the novel The Martian, Andy Weir had a geeky web comic called Casey and Andy? This strip was very popular:
http://www.galactanet.com/comic/view.php?strip=39
lf(1): it's like ls(1) but sorts filenames by extension, tersely
I believe your math is wrong. U235 releases 202.5 MeV per atom undergoing fission, so that means 1 kg can generate 83.14 TJ from fission. Assuming 100% efficiency, a massless drive, and no mass loss from propellants, that means there is enough energy from fission to reach a velocity of 0.043 c relative to the rest frame.
dE = (m - m') c^2 = m' c^2 (gamma - 1) => m' c^2 = m c^2 (1 - dE/(m c^2)) = m c^2 (1 - rho)
rho = dE/(m c^2) = 83.14 TJ / 89.88 PJ = 9.25e-4
rho = (1 - rho) (gamma - 1) => gamma = 1/(1 - rho) = 1/sqrt(1 - beta^2)
(1 - rho)^2 = 1 - beta^2 => beta^2 = rho (2 - rho) = 1.85e-3
beta = sqrt(rho (2 - rho)) = 0.0430
http://www.americanthinker.com...
http://www.killclimatedeniers....
http://www.climatedepot.com/20...
Calling upon the government to execute those with a different point of view is something I'd consider a death threat.
Well, if the drive works, then either the symmetry underlying conservation of momentum isn't entriely true (it wouldn't be the first time we discovered a surprising lack of symmetry, you know), or the drive isn't entirely reactionless. I think it is important to always be willing to keep an open mind, when we don't know for certain; what you are saying is "No, impossible, so I am not even going to look". Personally, I think preservation of momentum is true; so in my view there must be an escape of momentum that we haven't figured - if this works. This doesn't strike me as unthinkable - after all, energy is put in, so it must go somewhere. We just need to find an explanation.
Here in Europe (specifically Germany) we always say a photon has mass because E=mc^2 but its rest mass is 0
No we do not say this in Europe and none of the Germans I have worked with at CERN have ever said this either because it is provably wrong. Photons have momentum but no mass. Either you had a really bad physics teacher or you did not understand what you were being taught. For a photon E=pc where 'p' is the momentum.
The problem with the paper is twofold:
1) After one year, it is still not published in a peer reviewed journal. This happens on occasion. However:
2) The data is about as flakey as it gets. Eg. the forces measured for the 60W power level range from 40 micronewton to 120 micronewton. This goes completely unexplained and all they do in the paper is some statistics voodoo to get some nice looking numbers out of this mess.
Well, I too think very little of Boris Johnson and Michael Gove, but where does your "in reality only about 18% of eligible voters voted to leave" come from?
According to https://en.wikipedia.org/wiki/... the UK (etc) turnout was 72.2%, of which 51.9% voted to leave and 48.1% (including me) voted to remain. Put another way, of the eligible voters about 37.5% voted to leave, 34.7% voted to remain, and 27.8% did not vote.