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Would This Work?


OrbitalBuzzsaw
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So I had an idea recently. First, you build a ring in low orbit, but locked to the planet by towers. Secondly, you run a smaller ring with magnets attached around at orbital velocity inside a copper-wire-lined enclosure. Wouldn't this generate a crapton of power for basically no operating cost beyond, y'know, space rings and elevators?

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Just now, Shpaget said:

And what mechanism do you propose that would extract it / convert to something that can be turned into something useful?

It's a big generator...

7 minutes ago, StrandedonEarth said:

The energy has to come from somewhere. Your magnet-studded ring would quickly stop as its kinetic energy is converted to electrical energy

No. Gravity.

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16 hours ago, Darnok said:

Magnetism itself is form of energy.

Oof. Oh no, no nooo.

You cannot extract energy from a magnet without first putting energy in. A magnetic field is not a source of energy although you can use it to store energy.

Think of a magnetic field as a spring. You cannot extract energy from a spring, its just a piece of metal. If you squeeze it though, you are putting energy in, which you can store in the spring and release later.

16 hours ago, OrbitalBuzzsaw said:

Gravity

Oh jeeze what is happening?

Its the same with gravity although because there is no repulsion force its a little different. Yes you can drop something into a gravity well and see energy come from that. But you can only do it once, if you dont add energy to the system, the object you drop will stay at the bottom of the gravity well forever. You're not really extracting energy from gravity, you are extracting it from the relationship between two seperated masses. You can add and subtract energy from that system, but you cant extract energy from a single mass's gravity well. Dont go banging on about collapsing the mass into its own schwartzchild radius, that is just an extension of the stored energy situation explained just above.

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And if place a lot of rings one above another, it will be a Dyson sphere.

 

22 minutes ago, p1t1o said:

 

17 hours ago, Darnok said:

Magnetism itself is form of energy.

Oof. Oh no, no nooo.

 

22 minutes ago, p1t1o said:
17 hours ago, OrbitalBuzzsaw said:

Gravity

Oh jeeze what is happening?

Mmmmm... The Love?

Edited by kerbiloid
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@p1t1o Thanks for explaining it much better than I could. 

OP: The bottom line is that your concept violates the law of conservation of energy. Never mind the engineering hurdles of building such a thing, it would soon stop as you extract energy from it. The energy has to come from somewhere, and magnetism and/or gravity won't provide it, they just facilitates the conversion. 

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Magnetism does no work. It is not a form of energy.

Magnetism is a force. But again, a force incapable of doing work.

To more fully answer the question: no, this would not work, and yes-maybe-kind-of this would work.

Setting aside deformations from other celestial bodies for a moment, the Earth's magnetic field rotates with the Earth (more or less; we're also ignoring the liquidity of the mantle).

If you put a ring up there in orbit not connected with the Earth, the ring would move through Earth's magnetic field and a current would flow around the ring. However, if you tapped that current (and you would have to, to keep the ring from melting), the ring would slow to a stop and fall out of the sky, because energy must come from somewhere, and the energy creating the current is the energy of orbit. To counteract this, you'd have to use station-keeping fuel. So you'd ultimately be finding an extremely inefficient and expensive way to trade rocket fuel for electricity.

If you attached the ring via a long pylon to the ground, however, then the ring would be 'orbiting' the Earth with the same period as the Earthly rotation. Therefore it would not move relative to the Earth's magnetic field, and therefore it would not induce a current.

 

Now, that last bit is a bit oversimplified. The magnetic field of the Earth doesn't quite move exactly with Earth's rotation, due to many factors (the liquidity of the Earth, deformations from celestial bodies and events, etc.) So you probably would be able to induce some current, especially with a very long ring (which you have). At that point, instead you'd be slowing the rotation of the Earth (albeit minutely, because she's a big'un).

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6 hours ago, p1t1o said:

Oof. Oh no, no nooo.

You cannot extract energy from a magnet without first putting energy in. A magnetic field is not a source of energy although you can use it to store energy.

Think of a magnetic field as a spring. You cannot extract energy from a spring, its just a piece of metal. If you squeeze it though, you are putting energy in, which you can store in the spring and release later.

You are wrong... take for example neodymium, this is your spring. If you put energy in it you add magnetic capabilities to this piece of metal. Now you have squeezed spring ready to make work (release energy).

Key thing is to develop mechanism able to drain energy stored in neodymium and of course you can not drain more energy than you stored :wink:

 

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6 minutes ago, kerbiloid said:

Just orienting its atoms, not storing an energy.
Making its structure to betray the Chaos and turn to the Order.

Yes, which means if you would be able to build device that would disorienting atoms of neodymium you should in result also get fraction of energy used in process of manufacturing neodymium magnet.

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