Does the EM drive (electromagnetic drive) work despite the apparent lack of propellant? In recent headlines, a supposed EM drive, or RF resonant cavity thruster, has been reported to produce thrust despite the apparent lack of any propellant. The drive is purported to work by pushing microwaves through a cone, thereby creating more force on the back end, pushing the object along. Naturally, the scientific community is skeptical that such a device can even exist. Popular Mechanics is blaming populism for the hype (is that irony?). Forbes insists "Physics Falls Apart If The EMdrive Works". The conservation of momentum seems violated by such a theory; there needs to be something of mass moving in the opposite direction to produce thrust. Yet, they, Eagleworks, claim to have something that produces thrust without expelling mass in the opposite direction. Are they lying? Does it work?

From the EagleWorks paper:

> The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust; however, none were identified.

They are not lying, they did detect thrust, but the source of that thrust remains a mystery. The fact that the EM drive would violate Newton's third law, one of the most established principles of physics makes this highly suspicious. Notice that they do not claim that the thrust could not be caused by experimental error (proving a negative is impossible) but that they simply were not able to detect one.

The paper does suggest an alternative theory (pilot-wave), but that in itself is not fully accepted by the scientific community (which doesn't mean it's wrong!).

In conclusion, thrust was measured, but it's not clear if the thrust is caused by experimental error or by currently ill understood quantum effects. The burden of proof lies with the proponents of the EM drive.