主题：三体里描述的星际发动机出现了 -- 北纬42度

analysis

Any claim of a reactionless drive is treated with skepticism by the physics community, since reactionless drives violate the well-established principle of the conservation of momentum, which has enormous experimental support. Shawyer claims that his drive does not violate the conservation of momentum.[11]

Since there are no known phenomena that do not conserve energy, any calculation based on standard physical theory that predicts a violation of energy conservation almost certainly is in error. This is a non-controversial and fundamental fact regarding the mathematical structure of the theories, regardless of whether the theories themselves are or are not correct descriptions of the physical world. Accordingly, the results reported regarding the EmDrive, if true, would demonstrate that existing physical theory (or its application in engineering) is incorrect or incomplete.

The EmDrive has been compared to the previous Dean Drive, in that an oscillatory motion is set up so that it has a different effect in each direction of the stroke, in the hope that momentum transfer will differ in each direction, except in this case the oscillations are said to be electromagnetic.

Conservation of momentum is also required and maintained in Maxwell's equations, Newtonian mechanics, Special relativity and quantum mechanics (and their combination, quantum electrodynamics), so this claim cannot be valid unless these well-established physical theories are false or can be otherwise explained in terms within these existing theories.

Shawyer's calculations[12] may be in error.[4] He may have incorrectly identified the forces on the sides of the waveguide. If an error is present, it is most likely that the 'thrust' is eliminated and the drive then cannot accelerate. Despite some criticism, Shawyer has released to the public a video purportedly demonstrating that his device works.

Any dispute will be settled when independent observations are able to conclude whether or not the machine works in the way it is claimed.