If you spin a generator in weightless space could you generate infinite power?
Of course the friction would be a issue but couldn't there be ways to reduce this in a weightless environment?
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Friction is ultimately where most power is lost in a generator system or any other mechanical system. The pull of gravity against interlocking objects, pressing them against each other, certainly causes some friction. The medium in which objects move also causes friction. In the weightless vacuum of space, both of these kinds of friction can be reduced to nearly zero, which is why we can have things like relatively stable orbit.
On Earth, engineers used to try to produce perpetual motion machines. To do this, the friction that would otherwise gradually slow down the machine must be reduced to a level that is negligible compared to the momentum in the machine. Even when this is achieved, you don't really have perpetual motion, unless friction is actually zero, but you could have the appearance of perpetual if the ratio of friction to momentum is low enough. This is what can be achieved in the vacuum and weightlessness of space - apparently perpetual motion.
Perpetual motion does not mean infinite energy. With your generator idea, you are trying to imagine something that escapes the limitations of the Law of Conservation of Energy. You are imagining a system in motion which stays in motion, and you recognize that motion is a kind of energy. But what you want to do next is to remove some of that energy and apply it to something else. When you do so, your system will slow down by at least as much as the energy you have used. When you generate electricity by spinning a magnet inside a coil of wire, the energy you get comes from pushing electrons down that wire. But what pushes the electrons? Have you ever used a device that generates some kind of power by turning a hand-crank? Do you ever wonder why there is so much resistance to turning that crank? It's essentially because you are pushing electrons with your hand. By turning the magnet, you induce a current in the wire. By inducing the current, you generate a magnetic field. That new magnetic field resists the field of the magnet you are turning. Ultimately, what you are feeling is the resistance of the momentum of those electrons wanting to remain "at rest".
But simply moving them is not the only work you have to do actually. Did you know there is friction at that atomic level? If you put a lot of power through a wire, the wire gets hot. That's from a kind of friction called electrical resistance. So what you would find if you have a "perpetually" spinning magnet in a space station is that as soon as you move a coil of wire over it, it will very quickly stop. If you had a light bulb attached to that wire in a completed circuit, it would glow briefly. You would also feel a tug on that wire. Then your energy is spent. The motion was transformed into heat, light, and the tug you felt on the wire. The end.