TallDave wrote:BTW, would you agree with the statement that a hypothetical M-E flywheel generator is 2L compliant because it increases the entropy of the causally connected universe by lowering its temp?
No. Entropy is a property of energy. Decrease the temperature, and you increase the entropy of each unit of
remaining heat - but you still decrease the total entropy, since the total amount of heat is less.
The energy that you pull out with your device brings the energy total back to the original level, but it's low-entropy, concentrated energy. (In theory (very simple, idealized theory), if it isn't heat, its entropy is lower than that of thermal energy at
any temperature - electrical energy can theoretically be used at 100%.) So the total entropy is still lower in the ideal case.
(Think about it in reverse. Heating up a uniform mess of particles by letting energy flow out of an electrical device is dead simple
and results in an increase in entropy. Why would the opposite
also result in an increase in entropy?)
This is one reason why I think the 'lowering the ambient temperature' idea is wrong. The others are that it doesn't seem to account for conservation of momentum, and thus also seems to break conservation of energy in most (not all) inertial frames. Fortunately it's not a cornerstone of M-E physics...
...
Of course, if we've really discovered Maxwell's Demon here (and I won't rule it out
a priori), I'll be delighted...
I may have just tripped over an unstated
caveat. This really needs more time than I have. I've got to get to work...
chrismb wrote:A hypothesis has been posited, based on Mach's principle, that thrust can be induced by reactionless means in an isolated system.
Actually, in contradiction to GIThruster, I think this
is very simply wrong. Specifically in its reference to an isolated system. The G-I flux enters and/or leaves your box, according to the theory; it is therefore not an isolated system.
You may say that since the theory is unproven, it is not known if this G-I flux exists. True. However, if we are to argue about whether or not an M-E thruster violates thermodynamic laws
in principle, we have to assume (for the sake of argument) that its operating principles are valid. Claiming that a working M-E drive would violate thermodynamic laws if M-E theory weren't valid is not an internally consistent statement.
chrismb wrote:There is nothing in need of 'explanation' by it.
Inertia doesn't have a widely-accepted 'explanation' right now, so far as I am aware. According to J. Woodward
et al., M-E explains it in the framework of GRT. It also predicts a space drive as a side bonus, which also happens to be a decent way to test the theory as an explanation of inertia.