Gravity certainly conserves momentum.When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

Quote from: ppnl on 05/04/2015 05:04 AMGravity certainly conserves momentum.When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction. PPNLI think you answered your own question here. Assuming the EM drive can create a gravity gradient, the created gravity well extends to infinity via inverse square law. It is essentially tugging at whatever is in front of it. The reason it tugs harder toward the front rather than the back is due to the front having a larger more shallow gravity well than the one in the back - the larger one wins.

Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Quote from: ppnl on 05/05/2015 02:21 AMNow if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.Thanks for your responseNo, from what I'm reading - constant input energy does lead to a sub-C speed barrier. What I visualize is happening is that as drive accelerates the shape of the frustum becomes more cylindrical until it is and there is no gravity gradient and therefore no more acceleration.I cannot attest to Shawyers statements nor prove that a gravity gradient is being created. I agree this is all conjecture at this point.

If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?

No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:http://arxiv.org/abs/0803.2811...from Cornell, and other sources regarding "Transmutation of Momentum"Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."Transmutation via the momentum planeR. Carroll andD. S. Jones CommunicaterArticle first published online: 6 JUN 2011DOI: 10.1002/mma.1670060129Copyright © 1984 John Wiley & Sons, Ltd

But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

Quote from: ppnl on 05/05/2015 03:22 AMBut if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.You get back to the perfect EM-Drive machine:Electrical Energy in = Delta Kinetic Energy + Delta Gravitational Energy.Which means that a chemically powered "Perfect" EM Drive cannot reach orbit* (Required: about 30MJ/kg) . It can however levitate to 100km altitude (Required: about 1MJ/kg - and atmospheric oxygen can be used for the first 50km), where upon solar panels can accelerate it to where ever.*Unless it dumps its fuel-product overboard like a normal rocket. So a fuel cell, then dump the water product away. In this case, a rocket-equation can apply, and I'm not sure if the device is that much better than a fully reusable single stage to orbit rocket.

2) here are some tests by Eagleworks and the thrust per watt.A) 1932.6 MHz 5.4 uN/W B) 1936.7 MHz 3.0 uN/WC) 1880.4 MHz 21.3 uN/WD) 2168 MHz no thrust detected, cause thought to be the lack of the dielectric resonator.And the China tests at 2.45 (2.457 seemed to be peak) with a dirty source and they got a lot of thrust as well.

Quote from: ppnl on 05/05/2015 03:22 AMNo I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.I haven't read anything regarding frame reference problems, I'll look into that - thanks for the tip.