EM drive actually works???? EAT THAT NEWTONIANS!

[bennyboy]

I don't get it... why shouldn't it work?
EM radiation has a clearly defined linear momentum.
Isn't this sort of the same principle as the solar sail?

Because it seems to violate conservation of momentum.

In a solar sail, net momentum is supplied by incoming photons. The momentum is transferred to the solar sail when the solar sail either absorb or reflect the photons. So momentum is conserved in a solar sail.

In other forms of propulsion, reaction mass is used to creat thrust. The spaceship gains momentum as the thrust accelerates the ship, but the gained momentum is precisely cancelled by the movement of reaction mass in the opposite direction, thus net momentum is conserved.

EM drive suggests radiation bouncing inside a completely enclosed and sealed vessel can produce a net thrust on the vessel. Nothing is bringing momentum into the system. The but alleged thrust on the vessel would accelerate the vessel, giving it momentum. but since no reaction mass leaves the vessel to cancel the momentum gained by the vessel, momentum is not conserved.

Saying EM radiation can create momentum were none existed before does not only go against overwhelming empirical evidence that momentum is conserved in all reactions hitherto observed, it also goes against maxwell's equation of how EM radiation works. So far there is no other hint that things are amiss with accuracy and precision of maxwell's equation. So it would be surprising if implicit momentum conservation of maxwell equation turn out to be in error.

Gravity moves things "for free," and we don't accuse it of breaking the laws of momentum. So does magnetism in a way.