Quote from: OnlyMe on 11/11/2016 05:07 pm In GR, which again is a geometric model describing the tidal effects of gravitation, momentum as a component of the math, is not an observable. It is a descriptive component of the geometric model.



Momentum as discussed in terms of the anomalous thrust and EmDrives is an observable... Even if it has not yet been conclusively observed in published data.



Here is something that I find really confusing... when we see a small object hit the Earth, we observe that its momentum has changed from non-zero to zero. On the other hand, we know that the total momentum of the system "earth + object" has not changed, so the Earth must have gained some momentum. Obviously this cannot be measured, but we know it must be true (otherwise CoM would be violated).

Quote from: wicoe

Now when we look at "anomalous thrust" devices (such as EmDrive), we observe that they apparently gain momentum. It would be logical to assume that this is caused by interaction with some other object (or objects) which are gaining the opposite momentum, but we don't know the mechanism of this interaction yet (woodward effect and interaction with other objects in the universe is one hypothesis). Why do some people choose to throw away CoM and assume that it's not "pushing against" (interacting with) anything?



Repeating myself.... What we know about momentum and the conservation of momentum is based on classical Newtonian mechanics, the way motion and momentum is transferred between billiard balls... and other collisions within our ability to accurately measure the masses and velocities involved before and after a collision... In many many discussions we then logically predict how what we know as a matter of direct observation applies to situations and conditions well outside our ability to accurately observe and measure. We do that very well. We are very clever and have an incredible innate ability to accurately imagine how what we do know might affect conditions we have not yet directly observed. As I said we are very good at this.., but we are not always right. That is why it is important to always remember the line that separates what we have actually observed and measured, from how we imagine and project those conclusions to unmeasurable conditions.For this reason while your statements above are accurate, that last qualification, "(otherwise CoM would be violated), becomes a dangerous assumption. We cannot know that what we do understand about momentum and the CoM has no limitations. There is more to the universe and physics that we do not know than we do know.To answer the question in that last sentence.., because within the context of classical Newtonian mechanics where our understanding of CoM is rooted, for every action there is an opposite and equal reaction. To move something you have to push it or it has to push against something else. That is what we have observed, measured and experienced... And it does not seem immediately clear that anything like that is occurring in the case of an EmDrive. So in an effort to hold our world view together we reach out for explanations... or we just reject the claims of an anomalous force as artifacts of experimental or systemic error. We all do the very best we can to protect and defend our world view (of physics) and what we have come to believe.Still many of those who might be labeled skeptics in these discussions, are just defending science itself by demanding that obvious sources of experimental and systemic error are addressed, and any apparent conflicts with established physics explained.