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Why after several positive tests, has the physics community not gone full throttle to try and disprove it, like they did with cold fusion? So far the tests hav

by madengr 10y ago

Why after several positive tests, has the physics community not gone full throttle to try and disprove it, like they did with cold fusion? So far the tests have been static torque? Could there be an interaction with the earths magnetic field?

deleted 10y ago
[deleted]
the8472 10y ago
China is shipping one up to their space station to test it there. That is already a pretty big allocation for research resources considering that there is a large prior against this working: conservation of momentum. So every time a positive result turns up incrementally more effort will be applied to test it, assuming the new result improves on previous ones. Seems like a reasonable approach to me.
- colordrops 10y ago
  I still haven't heard a good explanation why this must mean that conservation of momentum is being violated. Couldn't there be a new phenomenon at which forces act at a larger or more distant scale on other masses, similar to gravity? That seems more plausible than beating conservation of momentum.
  - the8472 10y ago
    Yes, physicists are more likely to look for new physics than toss out the the conservation. But the new physics would have to be fairly narrow since the standard model is fairly well-tested and consistent with most observations.
  - gus_massa 10y ago
    > Couldn't there be a new phenomenon at which forces act at a larger or more distant scale on other masses, similar to gravity? Gravity doesn't act at large distance. If you have a star like the Sun, it modifies the gravitational field locally. The modifications travel for a while and when the modification hits a planet like the Earth it applies a force to the Earth and modifies it's direction. The modifications are like the gravitational waves that have been recently measured. They travel at the speed of light. If you have a force that can truly act at distance, you can use it to transmit information faster than light and it will break special relativity.
    - colordrops 10y ago
      Well all experiments have been near large large objects so far, so if such a force exists nothing is being said about it being faster than light.
      - gus_massa 10y ago
        Near is very near here. Let's analyze a similar case. The weak nuclear force is transmitted by the W+, Z0 and W- particles. They live approximately 1E-25 seconds. Assuming they travel near the speed of light, they can travel 3E-17 meters. That is a very small distance You can think that an electron and a neutrino at 3E-17 meters can somehow interact at distance, because it's very small. But this is not true. The electron has to create one of the W+, Z0 and W- particles, send it to the neutrino, and the neutrino has to absorb it. Even 3E-17 meters is a long distance here, and it's possible to measure indirectly the properties of the intermediate particles. If the Em-Drive device somehow interacts with the floor, walls or the Earth that are a few inches away, this is a extremely very big distance for the current theories. The Em-drive must interact with some kind of field and create some intermediate particles, like photons, gravitons or some new particle. The problem is that if the Em-drive using some field and particles to conserve the energy and momentum locally, then the maximal theoretical output of a device that don't break the currently accepted physics laws is 1/c = 0.0033 mN/KW. I couldn't find in this article the experimental results in China, but it the recent "successful" experiment in NASA measured 4000x this value. [In my opinion, it was an experimental error.] Getting 0.0033 mN/KW is "easy" with a perfect light source, like a perfect laser. Less is easier with a real light source, like a real laser. More is theoretical impossible with the current physics laws.
- deleted 10y ago
  [deleted]
arcanus 10y ago
> Why after several positive tests, has the physics community not gone full throttle to try and disprove it, like they did with cold fusion? No one has any funding to research it. Despite the press, no major research agency is backing efforts to investigate the effect. Cold fusion actually did get serious funding back in the 80s, which made it 'higher profile' to the scientific community. I'll add that cold fusion seemed more plausible. In that it did not violate extremely well understood fundamental principles of physics, e.g. conservation of momentum. While incorrect, cold fusion was at least on the face of it a sensible inquiry at one time. The EM drive has extremely compelling reasons to ellicit extreme skepticism from the scientific community at large.
- mordant 10y ago
  >In that it did not violate extremely well understood fundamental principles of physics Cold fusion violated the fundamental principle of 'Where are all the dead grad students caught up in the neutron flux?'.

by madengr 10y ago

deleted 10y ago

[deleted]

the8472 10y ago

China is shipping one up to their space station to test it there. That is already a pretty big allocation for research resources considering that there is a large prior against this working: conservation of momentum. So every time a positive result turns up incrementally more effort will be applied to test it, assuming the new result improves on previous ones. Seems like a reasonable approach to me.

colordrops 10y ago
I still haven't heard a good explanation why this must mean that conservation of momentum is being violated. Couldn't there be a new phenomenon at which forces act at a larger or more distant scale on other masses, similar to gravity? That seems more plausible than beating conservation of momentum.
- the8472 10y ago
  Yes, physicists are more likely to look for new physics than toss out the the conservation. But the new physics would have to be fairly narrow since the standard model is fairly well-tested and consistent with most observations.
- gus_massa 10y ago
  > Couldn't there be a new phenomenon at which forces act at a larger or more distant scale on other masses, similar to gravity? Gravity doesn't act at large distance. If you have a star like the Sun, it modifies the gravitational field locally. The modifications travel for a while and when the modification hits a planet like the Earth it applies a force to the Earth and modifies it's direction. The modifications are like the gravitational waves that have been recently measured. They travel at the speed of light. If you have a force that can truly act at distance, you can use it to transmit information faster than light and it will break special relativity.
  - colordrops 10y ago
    Well all experiments have been near large large objects so far, so if such a force exists nothing is being said about it being faster than light.
    - gus_massa 10y ago
      Near is very near here. Let's analyze a similar case. The weak nuclear force is transmitted by the W+, Z0 and W- particles. They live approximately 1E-25 seconds. Assuming they travel near the speed of light, they can travel 3E-17 meters. That is a very small distance You can think that an electron and a neutrino at 3E-17 meters can somehow interact at distance, because it's very small. But this is not true. The electron has to create one of the W+, Z0 and W- particles, send it to the neutrino, and the neutrino has to absorb it. Even 3E-17 meters is a long distance here, and it's possible to measure indirectly the properties of the intermediate particles. If the Em-Drive device somehow interacts with the floor, walls or the Earth that are a few inches away, this is a extremely very big distance for the current theories. The Em-drive must interact with some kind of field and create some intermediate particles, like photons, gravitons or some new particle. The problem is that if the Em-drive using some field and particles to conserve the energy and momentum locally, then the maximal theoretical output of a device that don't break the currently accepted physics laws is 1/c = 0.0033 mN/KW. I couldn't find in this article the experimental results in China, but it the recent "successful" experiment in NASA measured 4000x this value. [In my opinion, it was an experimental error.] Getting 0.0033 mN/KW is "easy" with a perfect light source, like a perfect laser. Less is easier with a real light source, like a real laser. More is theoretical impossible with the current physics laws.
deleted 10y ago
[deleted]

arcanus 10y ago

> Why after several positive tests, has the physics community not gone full throttle to try and disprove it, like they did with cold fusion? No one has any funding to research it. Despite the press, no major research agency is backing efforts to investigate the effect. Cold fusion actually did get serious funding back in the 80s, which made it 'higher profile' to the scientific community. I'll add that cold fusion seemed more plausible. In that it did not violate extremely well understood fundamental principles of physics, e.g. conservation of momentum. While incorrect, cold fusion was at least on the face of it a sensible inquiry at one time. The EM drive has extremely compelling reasons to ellicit extreme skepticism from the scientific community at large.

mordant 10y ago
>In that it did not violate extremely well understood fundamental principles of physics Cold fusion violated the fundamental principle of 'Where are all the dead grad students caught up in the neutron flux?'.