“These force fields — the same entities that emanate from fridge magnets”
Not a lot of people know that :]
The magnetic universe begins to come into view
11–20 of 38 posts
Re: The magnetic universe begins to come into view
#12Bit 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…
Looks like it was placed in a normal agricultural field in the Netherlands. It is mostly long patches with "moats" at the sides (irrigation) like all the other ones around that location. And they made sure cows could not get on it by making it surrounded by a bigger patch of water as the observational stuff is placed in a circle, I guess. But this is a non-educated opinion based on observation only.
Re: The magnetic universe begins to come into view
#13If 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.
Electrostatic would be a better choice. A great example I've seen is on the Hyperphysics website. It calculates two electrons with like charges of 1 Coulomb for 1 second repel each other with a million tons of force.
edit: For magnetism I believe the force comes from virtual photons maybe electrostatic is on a different scale, either bigger or smaller.
Re: The magnetic universe begins to come into view
#14If 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 calcu…
>It would also only allow a one-way travel along the local field gradient. No round trips.
Turn the magnet around?
Re: The magnetic universe begins to come into view
#15Earlier quoted context omitted.
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 fram…
I want to know things like this. Any recommendations for books or lectures?
Re: The magnetic universe begins to come into view
#16Bit 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…
Not naturally occurring. Was shaped sometime between 2006 and 2007, give or take a year. The interface is a bit jerky.
Hit play button at the very bottom: https://earthengine.google.com/timelapse#v=52.91525,6.86982,...
Re: The magnetic universe begins to come into view
#17If this explains expansion, then it also eliminates dark energy, no?
Re: The magnetic universe begins to come into view
#18Earlier 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?
ViaScience has some very good lectures on physics.
https://www.youtube.com/channel/UCx6G76LCKLdd7__F0xt5POQ
Re: The magnetic universe begins to come into view
#19If 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 calcu…
Hmm... so bottle a magnetar and you get apparently (but not really) "massless" propulsion. All we have to do is bottle a magnetar... umm... without the magnetic field ripping the spacecraft and anything in it to shreds... and do it with quantities of energy small enough to control (and dissipate waste heat) without melting the spacecraft into a blob of liquid metal. Got it. :)
So slightly more imaginable than the Alcubierre drive in that it does not break known laws of physics or require vast quantities of unobtainium (negative mass, lots of antimatter, etc.), but completely impractical with current or foreseeable technology. Might also be fundamentally impractical since the energy/mass requirements to generate a field powerful enough to overcome gravity and other forces acting on the spacecraft might be too large... the thrust/weight ratio math might not work even for micro-gravitational fields.
Re: The magnetic universe begins to come into view
#20If this explains expansion, then it also eliminates dark energy, no?
If I read it correctly, it only eliminates the conflict between a couple different ways to measure the rate of expansion in the early universe. Dark energy is about the rate accelerating over time, which is a different thing. I do wish they had addressed it explicitly.