system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:The EM drive as spaceship propulsor; If they don't (exactly) know how it works and the force is produces is too small to measure on earth. How did they discover it?
gpt
The guy that invented it had a theory on how it worked. His theory is wrong, but when they tested it it really did apply thrust. Now no one knows why. It is more likely it's some interaction with the local environment than being some sci-fi tech though.