“These force fields — the same entities that emanate from fridge magnets” Not a lot of people know that :]
Well, not a lot of people understand magnetism anyway.
The magnetic universe begins to come into view
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Re: The magnetic universe begins to come into view
#22Bit 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/ma…
There are many strange and wonderful circles to be seen in the Netherlands. For example, the IJsseloog:
https://www.google.com/maps/place/IJsseloog/@52.5969321,5.73...
Re: The magnetic universe begins to come into view
#23If 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
Maybe if magnetism is combined with a gravitational slingshot it would be possible to extract energy.
Re: The magnetic universe begins to come into view
#24Bit 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/ma…
It's very common to see these water ditches in the Netherlands, since 1/3 of the country is below sea level. Land rescued from water is called a polder: https://en.wikipedia.org/wiki/Polder
Re: The magnetic universe begins to come into view
#25Earlier quoted context omitted.
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 fram…
I want to know things like this. Any recommendations for books or lectures?
Any undergraduate level textbook on E&M. Griffith's 'Introduction to Electrodynamics' is a commonly used one.
Re: The magnetic universe begins to come into view
#26Earlier quoted context omitted.
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 calcu…
> It would also only allow a one-way travel along the local field gradient. No round trips. Turn the magnet around?
As with the compass, the orientation of your magnetic dipole against the field is unstable, so now you need a second propulsion system for maintaining the unstable orientation of the dipole.
Re: The magnetic universe begins to come into view
#27Re: The magnetic universe begins to come into view
#28This has been a popular fringe scientific theory for many years under the title Electric Universe Theory. Fringe for sure, but its lead proponents tend to be real scientists referencing real, peer-reviewed literature.
Re: The magnetic universe begins to come into view
#29This has been a popular fringe scientific theory for many years under the title Electric Universe Theory. Fringe for sure, but its lead proponents tend to be real scientists referencing real, peer-reviewed literature.
The Electric Universe is a much different, much more wide-reaching bit of crackpottery than this.
Re: The magnetic universe begins to come into view
#30Earlier quoted context omitted.
> It would also only allow a one-way travel along the local field gradient. No round trips. Turn the magnet around?
As with the compass, the orientation of your magnetic dipole against the field is unstable, so now you need a second propulsion system for maintaining the unstable orientation of the dipole.
You don't need a second propulsion system, you could use reaction wheels[0].