the quantum vacuum plasma thruster works

[sykavy]

NASA: New "impossible" engine works, could change space travel forever

[RAMSET]

from your link

I like this Guys explanation of the technology

61Reply
swiftdropkick

Because it's proposing the equivalent of you sitting in your car, on a level road, with the transmission in neutral, with a baseball in your hand, and then bouncing said baseball repeatedly against the windscreen in order to make the car move forward.

Intuitively, it shouldn't work, since by Newton's Third Law when you throw the baseball forwards, there is an equal and opposite force pushing you (and the car seat back behind you, and thus the entire car) backwards. When the ball bounces off the windscreen, the car gets pushed forward by the baseball, but since there was already a backwards force on the car caused by you throwing the ball in the first place, the effect of the two forces will cancel each other out. The car won't move, no matter how many times or how hard you bounce the ball (i.e. no matter how much energy you supply to the system).

Replace "your car" with "sealed metal cavity", "baseball" with "microwaves", and yourself with a microwave generator (which is bolted to the sealed metal cavity, just like if you were seated right against the car seat's back), and you get the EmDrive.

Of course, my explanation was assuming "classical" mechanics (where all of Newton's Laws apply). The inventor of the EmDrive claims that there are some quantum effects at play that make it possible. Not knowing much, if anything, about the minutiae of quantum mechanics, I reserve my comments.

(Incidentally, even if you weren't sitting with your back right up against the seat back (which I assumed, for simplicity's sake), the car still wouldn't move as you bounced the baseball; you would move backwards for a bit, and the car would have a forward force acting on it once the baseball hits the windscreen, but you'd eventually hit the seat back, providing a backwards force to the car, and thus canceling out the movement