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posted by martyb on Friday June 17 2016, @12:39AM   Printer-friendly
from the invisible-light dept.

International Business Times writes:

A new peer-reviewed paper (open, DOI: 10.1063/1.4953807) on the EmDrive from Finland states that the controversial electromagnetic space propulsion technology does work due to microwaves fed into the device converting into photons that leak out of the closed cavity, producing an exhaust.

So how could something come out that you can't detect? Well, the photons bounce back and forth inside the metal cavity, and some of them end up going together in the same direction with the same speed, but they are 180 degrees out of phase. Invariably, when travelling together in this out-of-phase configuration, they cancel each other's electromagnetic field out completely.

That's the same as water waves travelling together so that the crest of one wave is exactly at the trough of the other and cancelling each other out. The water does not go away, it's still there, in the same way the pairs of photons are still there and carrying momentum even though you can't see them as light.

If you don't have electromagnetic properties on the waves as they have cancelled each other out, then they don't reflect from the cavity walls anymore. Instead they leak out of the cavity. So we have an exhaust – the photons are leaking out pair-wise.


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  • (Score: 3, Interesting) by deimtee on Friday June 17 2016, @01:57AM

    by deimtee (3272) on Friday June 17 2016, @01:57AM (#361364) Journal

    Wouldn't mean that you could get just as much thrust by using the same electric power to run a MASER? If the EmDrive is getting more thrust than a MASER would, then there is still some unexplained physics going on.

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  • (Score: 0) by Anonymous Coward on Friday June 17 2016, @02:23AM

    by Anonymous Coward on Friday June 17 2016, @02:23AM (#361370)

    What seems to be going on is phased photons provide more thrust just like laser beams are more coherent than flashlight beams.

    • (Score: 0) by Anonymous Coward on Friday June 17 2016, @02:32AM

      by Anonymous Coward on Friday June 17 2016, @02:32AM (#361373)

      That would violate conservation of momentum, so no.

      • (Score: 0) by Anonymous Coward on Friday June 17 2016, @02:12PM

        by Anonymous Coward on Friday June 17 2016, @02:12PM (#361545)

        OH SNAP!

        Soljua boy tell em!