The magnetic universe begins to come into view
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The magnetic universe begins to come into view
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Re: The magnetic universe begins to come into view
#2[deleted]
Re: The magnetic universe begins to come into view
#3Seems alot more interesting than yet another failed searched for "dark matter"
Re: The magnetic universe begins to come into view
#4If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.
Re: The magnetic universe begins to come into view
#5If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.
These fields can create forces, but they can't do work unfortunately.
Re: The magnetic universe begins to come into view
#6If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.
These fields can create forces, but they can't do work unfortunately.
A magnetic field can't do work by interacting with another generated field? If so how do electric motors work? I must be missing something here.
Re: The magnetic universe begins to come into view
#7Earlier quoted context omitted.
These fields can create forces, but they can't do work unfortunately.
A magnetic field can't do work by interacting with another generated field? If so how do electric motors work? I must be missing something here.
Electric fields do the work there. A charged particle in a magnetic field feels a force (Lorenz force) that act perpendicularly to its velocity. But work is only work if the force is applied in the direction of its velocity. Essentially it's changing its direction of momentum, but not its magnitude.
On the other hand, some magnetic fields (not all) can be transformed into electric fields by a change of reference frame. In that case, the electric field can be used to do work. But I don't believe that's possible on these scales.
Re: The magnetic universe begins to come into view
#8Bit of a tangent, but I was curious about the circle lake in that picture of LOFAR[1]. That can't be naturally occurring can it? It looks like a moat, and I see lots of irrigation channels nearby. But maybe it was carved by a glacier. There's another LOFAR location[2] next to a park that has a lot of glacial lakes in it.
[1] https://www.google.com/maps/place/LOFAR+superterp/@52.914715...
[2] https://www.google.com/maps/place/National+park+Dwingelderve...
Re: The magnetic universe begins to come into view
#9If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.
Way back in another life I did some calculations similar to that.
I don't remember details anymore, but there were some observations that some (deep space) astronomical object somewhere was accelerating and there were no models at the time that would explain that. I tried to explain it by a magnetic dipole in an non-homogeneous interstellar magnetic field.
If you know the gradients and the dipole moment you can calculate the force on the dipole.
I think it required a magnetar-level dipole to get some non-trivial forces out of the interstellar field. Anyway, I don't know if that theory ever got anywhere. Probably not. I never got any calls back from the people I presented that work to.
A spaceship would have a much lower mass than a star or whatever I was calculating that for, so I guess the requirements would be lower. Still, my gut feeling would be a magnet much beyond what you can do with today's superconductors. It would also only allow a one-way travel along the local field gradient. No round trips.
Re: The magnetic universe begins to come into view
#10If magnetism pervades space, can interaction with these fields generate force for propulsion? These fields are weak but what about extremely powerful superconducting magnets? Even if the force is small it could add up over long periods, and since no mass is needed it would be a "massless" drive that does not violate any physical laws.
For similar reason you can't use Earth's magnetic field to lift stuff - it's so weak you need impractically strong magnet (note) and/or impractically big and at the same time lightweight structure.
(note) and it must not be permanent magnet, as the sibling explains - you must vary the magnetic field to "convert it" into electric field which then does the lift