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# Space coil generator

Huge rings of copper orbit the earth generating electricity.
 (+2, -1) [vote for, against]

Our high school physics classes all taught us some basic principles about electromagnetics. One of which is a ring (capable of efficiently conducting electricity) traveling through a magnetic field creates a current in the ring. Another basic idea taught is the fact that the earth has its own giant magnetic field (hence compasses)...but we all knew that already. If we have a giant ring that orbits around the earth through the earths magnetic field, it will generate energy (an electric current) that could be sent to the surface with microwaves or something. Here's a formula to refresh your memory if you don't remember.. magnetic field=(vacuum permeability constant - current generated)/(2pi x radius of ring)

If we start bringing up bits of copper on each space mission and leave it in orbit around the earth, we could assemble it into ring once we have enough up there. (since itd be impossible to build 'em here and bring them up, they'd be too big). Each huge ring has a microwave device to send the energy to the surface (I have no idea how the microwave thing works...guess we'll subcontract that one out). There we go! A new, never ending source of energy thats more or less safe... (just ignore the microwave beams going crazy and killing thousands like they do in SimCity 2000).

 — blaah, Sep 23 2001

Electrodynamic Tethers http://en.wikipedia.org/wiki/Space_tether
Sort of baked, in an improved form. [bdh, Oct 27 2005]

Sun's magnetic field http://en.wikipedia.../Sun#Magnetic_field
[spidermother, Feb 18 2011]

[link]

I guess great minds just think alike...muahaha (busily building plans to blow up sun)
 — blaah, Sep 23 2001

 No.

 Just like a conventional generator, you're converting kinetic energy into electrical energy. That is: as you generate electricity with these coils, you slow down their motion. Eventually they fall out of orbit, and all you've done is reclaimed a fraction of the energy you expended launching them in the first place.

 Bad idea. Not even a novel bad idea -- I've seen it proposed in books that really ought to know better.

Where electromagnetic tethers or space coils might be useful is not in generating power but in adjusting the orbit of a satellite without expending fuel. (Instead, you use electrical power from solar cells.) But this is a well-researched topic.
 — egnor, Sep 24 2001

 Specifically, if the rings are spinning in one direction and generating electricity, electromagnetism will create a force on them in the opposite direction, because of the law of conservation of energy.

Fishbone. The rules specifically say not to post perpetual motion machines.
 — PurpleBob, Oct 20 2001

It's actually is possible and energy efficient if the orbital kinetic energy doesn't come from the launch vehicle itself. For example, if you can tow into Earth orbit around the magnetosphere a N.E.O. (near earth object) meteor so it is permanently captured into a stable orbit around the radiation belts then land on the meteor with the satellite you used to gravitationally tow it with and anchor the coils there, the result would not be a net loss in energy conversion from launch energy because you're using the natural orbital velocity of the meteor.
 — technatezin, Feb 17 2011

if you use the orbiting object as a generator the object will be slowed and its orbit will degrade. the NEO can only deliver as much energy as it contains in velocity which IMHO is not a safe game to play with the earth nor a reasonably efficient form of energy generation.
 — WcW, Feb 17 2011

Does the solar system as a whole have a magnetic field?
 — MaxwellBuchanan, Feb 17 2011

Yes - about 5 nT at the orbit of the Earth (link).
 — spidermother, Feb 18 2011

 WcW wrote: "IMHO is not a safe game to play with the earth nor a reasonably efficient form of energy generation."

 For small meteors this would not be a problem. If telescopes (both ground based and space based) can track them, they could also reasonably determine their size, so only meteors determined small enough to burn up in the atmosphere would be towed into Earth orbit.

 Further, a proximity beacon can be placed on the satellite and generating coils so we would know to very high precision where the meteor is in the sky. Destroying it would not be a problem, but why even do that?

 If we know exactly where the meteor is in the sky and if it's orbit degrade to where it is no longer useful for power generation then because of the proximity beacon we could easily land another satellite on it and mine it out for valuable minerals.

 It's a win-win situation if it's done right.

 The world's population is exploding and industry is quickly running out of minerals for it's manufactured products and power plants, so at this rate of consumption, we'll hit ecological collapse long before we need to worry about meteor impacts. Going to space to mine meteors to feed the Earth's billions is the next logical step.

In any case most scientists agree that if we stay on a single planet without developing space faring technologies we will very likely also die on it from many other causes: epidemics, ethnic hatreds, superstition, political and resource wars, pollution, etc..... It's like a stewing pot.
 — technatezin, Feb 18 2011

.... another planet will solve those problems?
 — WcW, Feb 18 2011

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