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> Isn't it just the reverse of a solar sail to send out the photons yourself rather than catching them?

No, that'd be the case if it were open but it isn't. As I understand it, it's an entirely closed system. That's what's controversial, there's nothing coming out of this "thruster", not even photons.

There's an image on page 3: http://www.emdrive.com/yang-juan-paper-2012.pdf

(disclaimer, I only have a hazy understanding of what this is supposed to be)



Wouldn't it be relatively straightforward to repeat the Chinese test in a garage? We're talking a whopping 70 millinewtons here, so equivalent to the weight of 7 grams. Some shrews are lighter than that.

Microwave science has this strange aura, since the stuff that happens in cavities etc is not exactly obvious at first sight. http://en.wikipedia.org/wiki/Cavity_magnetron


I checked again. Some insider said the Chinese machine does produce 80 millinewtons, but it's less efficient than the NASA one since they take way more power input.


sorry to disappoint you, but it's actually 30~50 micronewtons, which is only 0.04g.


> As I understand it, it's an entirely closed system.

You got the gist correct. The microwaves are supposed to be completely contained.




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