Timeline for How could a technological society exploit an absurdly strong, permanent magnetic field?
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
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| Apr 24, 2018 at 21:02 | comment | added | Glurth | @Samuel "de-orbits the station" So this could this be used to intentionally slow down an orbiting craft without propellant? | |
| Apr 23, 2018 at 19:53 | comment | added | Samuel | @Glurth Sure, until the drag de-orbits the station. You'll end up with less energy that it took to get the thing in orbit or would use more than you spend to keep the thing in orbit. That's a terrible way to convert chemical energy (rocket fuel) into electricity. | |
| Apr 22, 2018 at 8:04 | comment | added | Glurth | How about in an orbiting space-station? A simple magnet, for example, will continue to act like a compass and point at the planet, while the station orbits. From the station's point of view, (unless it happens to be rotating at exactly the same speed), the compass will appear to spin once per orbit. Surely power can be extracted from such a setup, no? | |
| Apr 20, 2018 at 23:33 | comment | added | AlexP | @Kaosubaloo: The point is that that the total work done by the field on a magnet which moves on a closed path is zero. You are right that the field would do work on part of the path; but that work will be exactly compensated on the return path. Think by analogy of Earth gravitational field; if you have an object falling the field does work, but if then you need to bring the object to the starting point you give back the exact same amount. | |
| Apr 20, 2018 at 22:58 | comment | added | nijineko | Electromagnetic fields under load produce drag and friction, contrary to popular understanding. Thus they would stop in a matter of seconds once you place a load on the electrical current. Some guys at the local power plant demonstrated this with a bicycle powered generator and a few electrical appliances with different power draws. A light bulb doesn't do much, but hook a hair dryer up to it and suddenly it's hard to pedal. Switch to a vacuum cleaner and suddenly it's almost impossible to pedal. | |
| Apr 20, 2018 at 22:45 | comment | added | Kaosubaloo | Woops I was wrong about it not being static. Please disregard that, but the rest of my statement stands regardless. | |
| Apr 20, 2018 at 22:21 | comment | added | Kaosubaloo | @AlexP I'm not sure I understand why this wouldn't work. Surely the field would be expending energy on the magnet regardless? The implication is that this magnetic field is strong enough to overcome gravity. Therefore, any object effected by the field would necessarily draw energy as it repulsed or attracted objects in opposition to gravity. For that matter, the question does not actually specify that the field is static in the first place, only that it is ridiculously strong and generated by a geological object. | |
| Apr 20, 2018 at 21:55 | comment | added | Samuel | A static magnetic field can't be used for energy generation anymore than a gravitational field can. You can't 'drain' a gravitational field, why should you be able to drain a magnetic field? | |
| Apr 20, 2018 at 21:42 | comment | added | AlexP | Well then, you have invented a perpetual motion machine... The downside is that perpetual motion machines don't work. You cannot extract energy out of a static magnetic field because there is no energy there to extract. (Time-independent magnetic fields are conservative, meaning that the total work done by the field on a magnet moving on a closed path is zero.) | |
| Apr 20, 2018 at 21:08 | comment | added | The Square-Cube Law | @AlexP No. I may throw a joke here and there but this one is serious. | |
| Apr 20, 2018 at 21:02 | comment | added | AlexP | This is intended to be taken humorously, yes? | |
| Apr 20, 2018 at 20:57 | history | answered | The Square-Cube Law | CC BY-SA 3.0 |