The proposed radio frequency (RF) resonant cavity thruster is unlike conventional thrusters and uses no reaction mass and emits no directional radiation. Designed using principles that are not supported by prevailing scientific theories, it apparently violates the law of conservation of momentum. The EmDrive, has roiled the aerospace world for the several years now, ever since it was proposed by British aerospace engineer Robert Shawyer. The essence of the claim is that by bouncing microwaves in a truncated cone, thrust will be produced out the open end. Most scientists have snorted at the idea, noting correctly that such a thing would violate physical laws. However, prestigious organizations like NASA have replicated the results showing thrusts.
MIT Technology Review has some reasoning on the subject, (possibly pay-walled) with a picture of the device. It's supposedly the so called unruh effect at play. When NASA tested the device, they measured with input of 17 W an average thrust of 91 µN (5.4 µN/W). A Chinese team used 2500 W and measured a thrust of 720 mN (288 µN/W). The expected radiation pressure is closer to 0.003 µN/W.
(Score: 2) by q.kontinuum on Friday April 22 2016, @05:13AM
Nice comment, but since I (currently) read on a (not that)smart-phone I'd really appreciate links as reference to the xkcd 955 [xkcd.com] instead of typing on this pesky little display...
Registered IRC nick on chat.soylentnews.org: qkontinuum
(Score: 2) by isostatic on Friday April 22 2016, @07:32AM
Well I wrote the post on a phone and doing html is a pain.
When it comes to xkcd I assume people have a photographic memory and don't need a link :D