Quote from: Robotbeat on 02/08/2013 05:49 amEverything about it obviously breaks the fundamental laws of physics, starting with (local) conservation of momentum.Are you even sure about that? It really does not seem obvious to me.
Everything about it obviously breaks the fundamental laws of physics, starting with (local) conservation of momentum.
Quote from: jded on 03/08/2013 08:02 amI have a different problem. If the inertia depends on the interaction with the rest of causally connected universe, shouldn't it change over time as far-off mass leaves the casually connected sphere? Especially, shouldn't it be dramatically different in the early universe?The idea that it depends on how much mass is in the "causally connected universe" is nuts.
I have a different problem. If the inertia depends on the interaction with the rest of causally connected universe, shouldn't it change over time as far-off mass leaves the casually connected sphere? Especially, shouldn't it be dramatically different in the early universe?
The idea that an effect here and now on an object depends on whether a causal link could happen at any point in the future is crazy. It's confusing instantaneous causality with future causality.
The vast majority of reputable physicists ignore Woodward. ... Don't you think that if there were anything to it by now at least one reputable physicist somewhere would have noticed? ... At least one reputable physicist did carefully consider Woodward's theories and wrote up an analysis that said they were bogus. Don't you think if the analysis itself was flawed some other reputable physicist would have noticed the analysis was flawed?
It is held by Mr. Woodward and the proponents of his theory that inertia, as they deduce from Sciama, is an instantaneous connection between local matter and the rest of the universe.
Quote from: ChrisWilson68 on 06/13/2013 07:50 amThe vast majority of reputable physicists ignore Woodward. ... Don't you think that if there were anything to it by now at least one reputable physicist somewhere would have noticed? ...At least one reputable physicist did carefully consider Woodward's theories and wrote up an analysis that said they were bogus. Don't you think if the analysis itself was flawed some other reputable physicist would have noticed the analysis was flawed? I have read most of the published material. It is impenetrable. The problem with those other "reputable physicists" is that the material is no mathematical walk in the park for them either. Besides, who will fund their time to get up to speed?Probably, they're waiting for Woodward's group to float one of the devices into a room.
The vast majority of reputable physicists ignore Woodward. ... Don't you think that if there were anything to it by now at least one reputable physicist somewhere would have noticed? ...At least one reputable physicist did carefully consider Woodward's theories and wrote up an analysis that said they were bogus. Don't you think if the analysis itself was flawed some other reputable physicist would have noticed the analysis was flawed?
I'm still not totally sold on his theory; I haven't had the time or mental energy to really dig into his math. But so far as I can tell from the available data, his devices do seem to work.
Given that you still seem to be under the impression that Woodward's theory requires instantaneous communication with distant matter, I don't see why I should accept your conclusions regarding it.It's not new physics. It's neglected physics. The basics were worked out in the '50s and '60s, based solely on General Relativity, by Stephen Hawking's doctoral supervisor. Whether it means what Woodward says it does - that's the part I haven't figured out yet. But it is IMO pretty arrogant to claim that it can't before either studying the theory in detail or reading up on the experiments, when it isn't obvious that it violates any well-established physical principles.
What I wanna know is what it has to do with spaceflight... other than grandiose claims about what it might mean for spaceflight if it works - in which case, we might as well talk about unicorns as I hear you can ride them to Mars without even a spacesuit.
Quote from: QuantumG on 06/14/2013 06:32 amWhat I wanna know is what it has to do with spaceflight... other than grandiose claims about what it might mean for spaceflight if it works - in which case, we might as well talk about unicorns as I hear you can ride them to Mars without even a spacesuit.Well the shortest answer is that it would eliminate the #1 ending reason for ending the life of a communications satellite because they would never run out of fuel for station keeping. That's worth $$$ to the operators of communications satellites would could lower the cost of your satellite TV subscription.
What is the relevance of Skylon/SABRE, or reusable Falcon 9, to spaceflight, other than grandiose claims about what it means for spaceflight if it works?
Discussing the possibilities stemming from a development is pretty standard on these forums, unless you're in L2 or an update thread. As far as I recall, Mach effect actually sees surprisingly little of that; most of the discussion is about whether or not it can work at all, and its potential for revolutionizing spaceflight is mostly left to the imagination.
For example, suppose someone hands you a 5,000 page purported proof that pi is rational. You needn't read and understand even a single page of this proof to correctly conclude it is wrong. It is enough to know there is a valid proof of the contrary, that pi is irrational.
No, this is not true.Inertial reaction is instantaneous, yes.
Indeed, there is no apparent reason for the time-reversal symmetry breaking which singles out a preferential time direction, that is which makes a distinction between past and future. A time-reversal invariant theory is more logical and elegant.
The requirement of time reversal symmetry, in general, is difficult to conjugate with the principle of causality.
It is postulated that GM/R, where M and R are the mass and radius of the observable universe, is invariant and equal to c˛.
As another example, take the EmDrive. It's inventor claims that bouncing microwaves around a closed container in a clever way leads to a net force on the container.
Instantaneously transferring inertia with the entire rest of the universe (or some large part of it) violates the second law of thermodynamics.
No, Sciama never claimed the Woodward Effect or anything like it was true. Woodward and his circle simply claim they are basing their theory on his work, and Sciama is conveniently dead and unable to protest having his name be sullied by association with the Woodward Effect.