Ignoring the fact that you're simply wrong for a moment, so what if it has?Do you think the millions to billions of dollars required to make this functional are going to start flowing just because of a lab demonstration?

Emdrive is a working system.

Do you think the millions to billions of dollars required to make this functional are going to start flowing just because of a lab demonstration?

Otherwise, I'd have to ask what is the point of lab demonstrations to funding agencies in the first place?

They could probably rig up a battery of flywheels, and get them spinning at various speeds, and convert the angular momentum into forward momentum.

Quote from: JohnFornaro on 03/30/2011 01:57 PMThey could probably rig up a battery of flywheels, and get them spinning at various speeds, and convert the angular momentum into forward momentum.Facepalm.

...I keep trying to believe in the conversion of electrical energy to forward momentum. ...

Having thought a bit more: Gyroscopic ACS is widely used for satellites. Is that active principle only angular momentum? Which would mean that circular motion is only good on the surface of a planet, where gravity and friction provide that which must be pushed upon.

Quote from: JohnFornaro on 03/31/2011 01:11 PM...I keep trying to believe in the conversion of electrical energy to forward momentum. ...What's belief got to do with it? I hope it works but I wait to see evidence, and practical application.e.g. I don't believe my car works, I know it from experience. Belief is only necessary to justify an emotional stance, when there is insufficient evidence.

.Unfortunately, it can be shown that in GR this "Sum for inertia" of the effects of the individual accelerations cannot exactly duplicate this effect, mainly because in GR the gravitational constant G is fixed, but the sum depends on the distribution of the masses of the universe and therefore cannot be fixed. This means that either this neat Mach's Principle model is wrong or GR is wrong. (I personally suspect that GR is an approximation which is very accurate at the solar system scale but very inaccurate at larger scales)."Is this accurate? If Dennis Sciama's model is correct, then it invalidates GR? Can someone explain?

No way to observe the difference? How useful a property is that?

Hard to say, I have no idea what explanation this comment is referring to by "it can be shown."I think in Woodward's derivation that the statement "the sum depends on the distribution of the masses of the universe and therefore cannot be fixed" would be dismissed pretty easily -- in fact I think IIRC effectively the distribution of the masses in the universe is fixed, due to the increasing effect of the greater amount of mass at greater distances. So in other words, although it is NOT fixed, it is close enough for GR to see no difference.In fact it's parallel to the argument that first-time viewers of ME theory often raise, that if inertia was gravitational in nature, you would see the effect of local masses (such as the earth, Jupiter, or the Sun,) very easily because they are so close. In fact Woodward shows via calculation that, counter-intuitively, the local masses actually have a 9-to-10 orders of magnitude smaller effect than the "distant far-off active mass," (i.e. all other mass inside the observeable universe horizon), despite their much farther average distance, due to the (literally) overwhelming mass differential of the rest of the mass.So basically from the viewpoint of any local mass, "G" is effectively fixed. There's just no way to observe a difference. So GR is valid even in an ME universe.

I found this comment on physicsforums.com pertaining to Dennis Sciama:"Note that linear frame-dragging works like inertia, in that a test object experiences a force proportional to its mass m if nearby objects are accelerating relative to it. It would be very neat if this could be extended so that when everything in the universe is accelerating relative to it with average acceleration a, it experiences a force exactly equal to ma. From the point of view of the rest of the universe, that force would then appear to be due to the inertia of the test object opposing its acceleration (in the opposite direction), and requires an equal and opposite force to maintain the acceleration. This is pointed out in Dennis Sciama's 1953 paper "On the Origin of Inertia". This idea is one of the possible simplifications that would arise from a gravity theory that satisfies Mach's Principle.Unfortunately, it can be shown that in GR this "Sum for inertia" of the effects of the individual accelerations cannot exactly duplicate this effect, mainly because in GR the gravitational constant G is fixed, but the sum depends on the distribution of the masses of the universe and therefore cannot be fixed. This means that either this neat Mach's Principle model is wrong or GR is wrong. (I personally suspect that GR is an approximation which is very accurate at the solar system scale but very inaccurate at larger scales)."Is this accurate? If Dennis Sciama's model is correct, then it invalidates GR? Can someone explain?