Tuesday, November 22, 2016

The EM drive produces thrust (or does it? really...)

The paper that was much awaited has been published [1].

To summarize why people find this fascinating -

1) All propulsion systems are based off Newton's third law. In order to generate thrust you have to shoot something out the back. Usually this stuff-that-flies-out-the-back is called the "propellant". And you have to have enough of this stuff to continue to produce thrust. The quantum cavity drives are supposed to  get around that issue making the entire process of space travel a much lighter affair.

2) An enduring mystery in known physics is the mystery of "mass". We know how to "measure" it by comparing the force acting on various objects - but we really have no idea where it comes from. Since it is tied to several other conserved quantities (Energy, Momentum, etc...) - it is fundamental to all known physics yet very little is actually understood about it. When one gets around the the core ideas of Newton's third law, we have to ask ourselves what is mass really.

3) Photons bouncing around a cavity should impart random momentum kicks to the walls. In any system which is in equilibrium, these momentum kicks should average to zero otherwise we have a Szilard engine where Maxwell's Demon is somehow sorting all the momentum kicks and only allowing kicks in one direction to act on the walls. There are competing ideas for Maxwell's Zombies, which people find interesting also. Is such a creature active in a quantum cavity drive?

Now before (or after) you run down the street naked holding you I-pad and shouting "President Elect Donald Trump made Free Energy Happen!!!!"

You should look at this graph

Not that it will matter to most who read this article - but error bars tell a story.

Happy sharing on Facebook or Twitter or Gab or Reddit.


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