Sister blog of Physicists of the Caribbean. Shorter, more focused posts specialising in astronomy and data visualisation.

Tuesday, 22 November 2016

For the record...

I'm just going publically on the record to state that the EM drive does not work and it will go the way of cold fusion and all the other pseudoscientific claims before it. That is all. Have a nice day.

13 comments:

  1. Alun Jones "It's been peer-reviewed"... usually heard just before a sequence of horrific screams, as the reviewer is pinned down and skinned alive, when the results are not reproducible. Happens often enough, I'm told. With enough time, they say you get used to the screaming...

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  2. I'm still waiting for the big-bang to be experimentally reproduced or for a study to be done where gravity is compared to a placebo.

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  3. Well something's happening. This seems like a good opportunity for a "wait and see" attitude.

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  4. From the High Chair of the Department of Poorly Understood Physics:
    I'm wondering if the EM drive "hasn't been built correctly" yet, even by the inventors and others with interest. For example, if I see something approaching that could cause me harm, I get out of the way by moving a short distance in a direction orthogonal to the oncoming threat. If other things also acted the same way, that harmful something would be moved by the differential in probable interaction that is slightly lower in front and higher in back. I call this juxtaposition of forces the Oh-Crap/High-Five engine. Pairs of threatened objects give each other a high-five and move rapidly out of the way of the oncoming threat. The energy expended during the high-five maneuver is regained after the threat passes during an OMFG-Hug. Detection of an oncoming threat may consist only of observing an adjacent Oh-Crap/High-Five drive activation. Skeptics are invited to think of the High-Fiver/Huggers as virtual particles in the vacuum. The High-Five event may occur in a manner analogous to a magnetic material absorbing enough energy from the surroundings to exceed the Curie Temperature, thereby leaving the pair with lots of angular momentum and no residual attraction until the amount of local energy is low enough the High-Fivers re-pair. If you wish to think of the High-Fivers as magnetic monopoles, I have no immediate objection.
    Those who do not learn from hysteresis are destined to repeat it.

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  5. A tiny effect within the margin of error of the experimental apparatus?

    Almost certainly measurement bias.

    Passing peer review just means that they did the math right, for the most part.

    Remember that on the first runs they saw the same "thrust effect" on the dummy load, which means that there was nothing special about the EM Drive load.

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  6. Christopher Butler Naah. It's claiming to violate a result so well-established it would be basically magic. Of course they can and should test it, just in case, but my prediction is that it's absolute bupkis. Best case : it's some super-weird quantum effect that can't be scaled up. Infinitely more likely : it's a measurement error.

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  7. When the results fail to be reproduced it will at least give the conspiracy theorists something to talk about. Clearly NASA is back engineering technology from an alien spacecraft and are now burying the evidence.

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  8. The effect is very tiny. Their thrust the same as the weight of 1/10th of grain of sand or 3 snowflakes.

    wolframalpha.com - Wolfram|Alpha: Computational Knowledge Engine

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  9. Ion Engines also have very low thrust, but it adds up after they run for a while.
    Ion thrusters have an input power need of 1–7 kW, exhaust velocity 20–50 km/s, thrust 25–250 millinewtons and efficiency 65–80%.
    https://en.wikipedia.org/wiki/Ion_thruster

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  10. Ion engines don't violate the laws of physics.

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  11. Something strange going on.. so definitely worth the time and energy to investigate and nail down more or less the demon drive

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