I'm pretty confident that the EM drive doesn't work (or, less likely, emits radiation / loses mass we have not yet detected). However, I've been cautiously hopeful we might see some challenging discovery in physics within my lifetime that requires additions / modifications to current theories, even major ones. I've been particularly hoping for things that would make it easier to do interplantetary and interstellar travel, as well as things that may allow us to avert the heat death of the universe. By the current laws of physics it is insanely difficult to go between stars, and it seems that we're all going to die.*
Which is why I spent an hour yesterday in reading about this thing, as it is about as good as any chance to discover something unexpected. I believe these were posted in the previous thread on the subject here, but I didn't read it then.
First off, a group researchers from Dresden ran
tests on the EM drive that challenge the claims (warning: PDF) the drive is producing useful thrust. They were able to observe thrust in different directions, and they attributed it to interaction caused by the power feeding lines, and the net useful thrust was not there.
Also a group of Chinese researches initially
reproduced the experiment and observed thrust (PDF). Now almost the same group of people published a second article that indicates that
once the wire interaction is discounted, the thrust can no longer be confirmed (PDF) (or I think it says so, as only the abstract is in English).
IOW, the EM drive seems to be a pile of poop. However, what I found much more interesting is the potential explanation for why it might work if it does (it does not). A researcher from Plymouth put forward
his own controversial theory as an explanation, suggesting it's caused by Unruh waves. Now, forget the explanation itself. I had a lot of fun reading about what the
Unruh effect actually is, which I had to do for the abstract of the article to start making any sense. It's pretty interesting. So interesting it nearly made me think the drive worked.
In reality, my hopes for
any breakthroughs are probably false, since there's enough reason to expect that current laws of physics are mostly complete and accurate for just about anything you'd come across, so probably any tweaks will be minor. And the EM drive would require quite a big one, or at least seems to. Now, finding one specific very narrow exotic phenomena that doesn't follow the law of conservation of momentum may not be as big a change as it sounds, as the law would still be true for everything else, but the EM drive sounds too simple to construct, which means it's not really that exotic.
(* We would have lived and explored more then enough until then, so it's not really a big deal, in fact there wouldn't be much point to live on for so long as a civilization, we would just be repeating our history over and over (bad parts included) at this point. But I have the tendency to get easily depressed by such prospects, so I've been stacking false hope against false problems. Solves them all right.
)
