I’ve read a couple of articles recently about a really cool experiment, EM drives. An EM drive is supposed to be a thrust engine that works by reflecting microwaves around inside it in a particular direction to create a very small propulsion. Now, I said ‘supposed to be’ because EM drives, if they worked, would actually violate the conservation of momentum. Nothing is coming out of the end of the EM drive, it’s not pushing off anything or pushing out anything. It shouldn’t be able to generate momentum out of nothing. Not to mention it shouldn’t be able to generate force via Newton's laws, which say that an external force has to cause motion, not internal forces. Essentially, you can’t hoist yourself up into the air Lorax-style. It’s a pretty solid and universally agreed upon law, along with the conservation of momentum. The EM drive shouldn’t work. But, a couple of experiments have measured a small net force being generated by the engine. This is exciting for a couple of reasons. Let’s go through the possibilities of what’s happening.
Option 1: the EM drive actually doesn’t generate thrust, and these experiments are wrong. This is the most boring option, with no violation of the laws of physics or any results, although people will certainly want to consider how multiple experiments got it wrong like this. Also, realistically, this is the most likely.
Option 2: the EM drive does in fact generate thrust, but the model of how it works is wrong. Either it is actually releasing microwaves out the back, or some other physics is interfering with our understanding of the situation. We get to keep our time-tested motion laws, but maybe we uncover new physics governing the system that we didn’t know about before, which would be sick. Some quantum effect or another causes the thrust or breaks our existing model, for example.
ALSO, this means the EM drive actually works and can be used! Because there’s no propellant or mass ejection in this drive, this could actually revolutionize space travel by getting rid of the fueling limits of modern rockets. It would be a great engineering challenge, as the current EM drives literally produce micro-Newtons of force, but the concept is scalable and even can be converted into a visible light/fiber optic system. Absolute game changer, this would be. You could literally have rockets just lifting off silently Star Wars-style. Interstellar civilization, here we come!
Option 3: the EM drive works, but the model is correct as well. This would be the most groundbreaking one, we’d have to literally re-figure-out and rewrite a lot of modern physics to fix it. So exciting! Also, there’s the same benefit for space travel as the one above.
Anyway, realistically, this is an Option 1 situation. Someone goofed with the experiments. However, there’s also a small chance that it is in fact Option 2, or even 3, which would be both really maddening and really exciting for physicists and aerospace engineers, not to mention me. I love physics-breaking experiments that make scientists mad!
Edit: Some newer experiments just conducted seem to indicate that the observed thrust was from errors in the procedures. *Sigh* Looks like an Option 1 after all. It's like the phosphine in Venus thing all over again. Dang it, Star Wars-style spaceships would have been awesome.
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