It's a machine that seems to produce a miniscule amount of thrust without a propellant. The laws of physics as we know them require that momentum always be conserved, but this thing seems to move without pushing on anything, which should be completely impossible.
Most likely what's happening here is a thermal effect or the machine pushing off the earth's magnetic field. Keep in mind that these things are very difficult to measure due to the tiny amount of thrust they may or may not produce. According to this study 1.2mN was measured, which is about the same amount of force as gravity exerts on 6-7 grains of rice (according to my back-of-the napkin calculation).
If this were real it would be absolutely huge, and destroy just about all of modern physics. It isn't just that we believe in conservation of momentum because we don't know of any way to break it, the equations we're using to describe things don't work without it.
This paper has a number of flaws. For example, the test really needed to be performed inside of a vaccuum to have any credibility at all, and whether that was the case was not made clear.
TL;DR It's most likely bunk, unfortunately, but it would be very revolutionary if true
The 6-7 grains of rice is an interesting comparison, but they actually they didn't get 1.2mN, they got 1.2mN/kW and they only tested the device with 40W, 60W and 80W and they got http://arc.aiaa.org/action/showPopup?citid=citart1&id=t3&doi... so they only measure a force of ~70uN, that is like 1/25 of a grain of rice, that's probably like a few grains of salt.
And then they use a "aggressive slope-filtering level" method (whatever it means) to get 124uN, that is still very small, like 1/10 of a grain of rice.
The results would be a great deal clearer if they could test it in a high vacuum at 2 to 4 kW. Measuring 3-4 millinewtons reliably is a lot easier to believe than a newton force equivalent to a tiny fraction of 1 grain of rice.
> the test really needed to be performed inside of a vaccuum
If I'm not mistaken they did, and the thrust was almost the same than the one in air. No perfect vacuum here, but still.
"Vacuum conditions are provided by two roughing pumps and two high-speed turbopumps, and all vacuum tests are performed at or below 8×10^−6 torr"
"The vacuum test data collected show a consistent performance of 1.2±0.1 mN/kW, which is very close to the average impulsive performance measured in air (also 1.2 mN/kW)"
According to Roger Shawyer, the inventor of the EmDrive, no physical laws are broken:
>What I would say is that the idea that EmDrive violates the laws of conservation of momentum is itself nonsense. Of course it doesn’t. It wouldn’t work if it did. All that EmDrive is a device for exchanging the momentum of the electromagnetic waves going up and down inside it, with the momentum of the thruster as it accelerates. It’s all actually elementary physics.
Most likely what's happening here is a thermal effect or the machine pushing off the earth's magnetic field. Keep in mind that these things are very difficult to measure due to the tiny amount of thrust they may or may not produce. According to this study 1.2mN was measured, which is about the same amount of force as gravity exerts on 6-7 grains of rice (according to my back-of-the napkin calculation).
If this were real it would be absolutely huge, and destroy just about all of modern physics. It isn't just that we believe in conservation of momentum because we don't know of any way to break it, the equations we're using to describe things don't work without it.
This paper has a number of flaws. For example, the test really needed to be performed inside of a vaccuum to have any credibility at all, and whether that was the case was not made clear.
TL;DR It's most likely bunk, unfortunately, but it would be very revolutionary if true