Re:The EmDrive just won't die
by dodobirdlord on Sunday September 13, 2020 @08:02PM
(#24465047)
No, momentum is simply outright conserved in the same way that energy is conserved. There are the two simplest to derive conservation laws, stemming from spatial symmetry (momentum) and time symmetry (energy).
These relationships are derivable via Noether's theorem, one of the most foundational results in physics.
They eject something from the system.
Re:The EmDrive just won't die
by kosievdmerwe on Sunday September 13, 2020 @12:59PM
(#24462201)
Rather the closed system includes both the craft and the ejected mass.
If you include the ejected mass, then momentum is conserved in that system. The ejected mass goes one way, the rocket goes the other. The momentum of the rocket is equal and opposite to the momentum of the ejected fuel.
Not true for the EmDrive.
Conservation of momentum only applies to mechanical processes, such as force and collisions. Converting energy breaks out of those bounds, and so it no longer applies - and the emdrive breaks no physics.
At least, that's how I've always understood it.