[PmbPhy (OP)]

The stated purpose of this forum is Heard an unbelievable science or medicine fact? I usually ignore such claims but recently I came across something worth mentioning because its passed peer scrutiny by independent scientists.

The EM drive being tested by engineers at NASA assert that this engine produces a measurable thrust without any propellant being expelled to conserve momentum. Its explained here

http://news.nationalgeographic.com/2016/11/nasa-impossible-emdrive-physics-peer-review-space-science/

Its been published too. See
Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum by Harold White, Paul March, James Lawrence, Jerry Vera, Andre Sylvester, David Brady, Paul Bailey from the NASA Johnson Space Center, Houston, Texas.

See: https://arc.aiaa.org/doi/10.2514/1.B36120

Amazing. More research needs to be done before any changes to the laws of physics can be proposed. After all, they have no idea why it does what it does.

The National Geographic website I posted a URL to comments that some scientists dismiss it as pseudoscience. I hold that those people are clueless because it has none of the defining characteristics of what is meant by the term "pseudoscience." The scientists are adhering to the scientific method quite rigorously. Those naysayers don't know what science is when they make such comments since we know from history that our understanding of science is constantly changing and any one observation can prove a law of physics of be wrong and no number of observations can prove a law to be right.

[chiralSPO]

I agree. These anomalous results should be given more scrutiny, not dismissed. My understanding is that the effect has been reproduced by at least two independent groups (including those at NASA who published). The effect was very small, but the change in momentum of the whole system appeared to be statistically significantly nonzero.

Could there be some underlying caveat or flaw in our understanding of momentum? Maybe, but I think the chances are extremely small. However, such a change in our theories would represent enormous potential for new theory as well as technologies that take advantage of this phenomenon.

The other (much more likely) possibility is that there was a mistake in the experimental design, or unfounded assumptions that influence the analysis of the data, maybe even a programming bug.

Whatever the reason, I think that figuring this out quickly should be a high priority. It reminds me of the "superluminal neutrino" measurements from a couple years ago. Everybody knew it was almost certainly a mistake, but they had to follow up on it with much rigor because of the possibility that underlying theory might have to be revised.

Personally, I hope that the EM drive is real. Not only would it open the door to more interesting theories on mechanics, but the utility of a such a drive for deep space exploration couldn't be overstated. Imagine not needing to lug propellent out of the solar gravitational well when embarking on interstellar travel!

[PmbPhy (OP)]

I know that some people who post here don't like to consider that our current understanding of the laws of physics might be incomplete or even wrong. To me the idea of being wrong is wonderful. Its only then do we learn something truly extraordinary and exciting.

In 1990 I heard some nutcase named "Dr. Bruce DePalma" on the radio claiming to have built a free-energy device based on the homopolar generator. People were calling in claiming to have built them and they also claimed that they worked. There was a pamphlet you could get for $10 which they asserted explained the operation of it. I studied the philosophy of physics in college and one of the most important things that I took away from that course was to keep an open mind because sometimes there was something interesting in what was otherwise nonsense. And this turned out to be one of those times. While the pamphlet was rubbished base on a very poor understanding of electrodynamics I did learn that the relativistic electrodynamics of a rotating magnet was not widely talked about in the physics literature. And in some places where it was the author got it quite wrong. A good example is how an astronomy text I have explained the force on charged particles by a rotating neutron star. The explanation was entirely wrong. Since then I learned the correct physics and am better for off it.

[Kryptid]

I hope it really does work, but I'm not counting my eggs before they hatch.

[PmbPhy (OP)]

I myself think that something is being misinterpreted but am willing to keep an open mind.

A friend of mine pointed out the following to me

The NASA experiment reminds me of an experiment done years ago in Taiwan (peer-reviewed and published) which claimed that the weight of a gyroscope has a slight dependence on its spin (antigravity!). The mistake in this experiment was ultimately identified as arising from a slight change in the mechanical  tension in the electrical cables connecting the gyro to the (external) power source.

I would suggest that the NASA people carefully examine the power connections that carry the electrical current from the external power supply to the internal  microwave generators that maintain the e.m. fields (the setup is probably very similar to that of a microwave oven placed on a sensitive balance). Also, I wonder how they eliminated the effects of the Earth's magnetic field on the currents sloshing around in the microwave generators and the walls of their cavity. And did they take into account that differential heating of the walls shifts the C.M.?