No external force = no source of energy.

no external force would imply perpetual motion, and that has conclusively been proven to be impossible. however, a windmill in space could certainly work for sure. you could use solar sails and put it in a geosynchronous orbit around the earth and feed the power back down a strong cable. however, because of finances i would say the idea is not viable.

The “windmills” in space would not spin forever without losing momentum. Windmills are used to convert wind energy to electrical energy. They do not create energy. In your scenario there would be a certain amount of friction created by the turbine. This would at the least slow the “windmills”*, eventually stopping them, or it would prevent them from spinning at all.

—*Edit, per @hiphiphopflipflapflop: the Windmills would indeed be more accurately called flywheels.

@Yetanotheruser Actually, they would just be flywheels and the extraction of energy from them would slow them down in addition to frictional effects. You would get somewhat less energy out of them than was put into them to spin them up in the first place.

@poisonedantidote this beanstalk/solar windmill would need to send a counterweight into higher orbit.

So only if a single object is put into motion in a single direction would that work, which in my case not possible?

@hiphiphopflipflapflop indeed. im not sure if that would be possible yet with out current technology. the mental picture i get is kind of similar to these proposed space elevators.

EDIT: i guess it would be better to just put solar panels on a station.

What is the difference from say me pushing the windmill causing it to move compared the wind causing it to move?

Is it just different types of energy itself?

@poisonedantidote Carbon nanotubes have the strength-to-weight ratio to just barely bring them into the realm of possibility, IIRC.

@hiphiphopflipflapflop i just hope they dont snap, that would be one hell of a towel whipping.

@Steve_A the friction caused by the energy conversion would still slow it down

@Steve_A You’ll need to stay up there spinning the mill to generate energy if you’re extracting energy at the same time. I don’t think you want to stay up there indefinately doing this.

Energy conversion itself causes friction, or is it the blades connection to the parts causing the friction? or both?

@Steve_A said: tied to what I call “energy blocks”

I think what you mean to say is Energon Cubes

@ninjacolin Yes! lol :D

if we have our hearts set on a windmill idea pushed by someone, why not just get a space suit and create a vacuum here on earth.

@Steve_A before you solve Earth’s energy problems, you’re going to have to invest in some study of thermodynamics. There is no getting around this (or indeed, around thermodynamics in general).

@poisonedantidote I just thought of it as an idea but it did not work. I failed haha…..

@hiphiphopflipflapflop I am not a scientist or good enough at math to try and attempt those fields best leave it the people who know it.

@Steve_A keep the ideas coming either way, its people who dare to say ’‘what if’’ regardless of how crazy it is that end up making the big breakthroughs.

A spinning object not connected to anything else (and: in a perfect vacuum, without gravitational tidal forces acting on it, and electrically neutral so it doesn’t create a magnetic field) will spin forever.

@Steve_A said: “I am not a scientist or good enough at math to try and attempt those fields best leave it the people who know it.”

scientists weren’t born scientists either.
you’re interested in this stuff and you have the creative mind to take a lot of knowledge a long way. why not become a scientist?

here is a crazy idea, how about putting a small highly magnetic man made asteroid in orbit around the moon, and then building a copper tunnel with copper cables for the asteroid to orbit round the moon inside of the tunnel.

@poisonedantidote That would brake the asteroid, causing its orbit to decay.

@hiphiphopflipflapflop how about 50.000 hamsters in tiny space suits running round on a giant tread mill? lulz.

anyway, im off to play some poker, have fun guys. put me down for one of whatever we end up building, energy bills are killing me

@poisonedantidote By god it might just work lol :D

@poisonedantidote You said something about magnets and all so its the attraction itself suppose to cause energy?

@hiphiphopflipflapflop What’s a good book to read up on thermodynamics?

@Steve_A The one I bought in order to revisit the subject at some future date is Modern Thermodynamics by Kondepudi and Prigogine. Bought on the strength of Prigogine’s reputation.

@hiphiphopflipflapflop Ok will check it out.

another question what is it called when you put something say a small amount of energy to create more energy?

Like if I wind something up will I only get the amount I put in or is it possible to get more energy out of it than before?

pendulum effect if that is correct thinking?

@Steve_A It’s not called anything because your notion violates the law of the conservation of energy.

@Steve_A Newtonian physics is also the order of the day. If you’re going to make real headway, you cannot do what the majority of non-physics majors do, and that’s take the cookbook approach to answering homework/test problems. You need to develop your conceptual understanding.

@hiphiphopflipflapflop This is a dumb question but how much energy would you say a toliet flush or water coming down pipes of a bath tube might cause?

That would be like hydroelectric power, which is possible right?

I see how it may be possible with solar panels but until we can develop beaming up blocks and beaming them down to earth, I think it would cost more to make the energy than what we would get in return.
Till this day I think solar panels are probably our most effective way. The sun is and endless source of energy. What we need to do is find an effective way of storing the extra energy collected for dark cloudy days or for storms that will last us at least a week.

http://en.wikipedia.org/wiki/Space-based_solar_power

@Steve_A A toliet works because it has a reservoir of water above the bowl. And that reservoir refills because the water utility has their BIG reservoir of water way above ground in a water tower. They use a water pump to keep that topped up.

@hiphiphopflipflapflop I was thinking when the water went down if passed some kind of friction it could cause energy? What if you were take that and multiply that by say a whole country (if it could happen) would you say it would create any decent amount of energy?

Like little tiny turning generators turned by the water flow of pipes

http://ga.water.usgs.gov/edu/hyhowworks.html ?

http://en.wikipedia.org/wiki/Hydroelectricity

In the case of a water pump pumping water into a water tower the pump consumes electrical energy and uses it to increase the potential energy of the water. This potential energy is used to maintain water pressure so that you can have running water from your faucet. If you were to collect energy from the water tower you would simply be re-collecting the energy that was put into it by the electric pump.

Understand that things do not “cause” energy. Energy is the potential of something to do work.

go shuttle go shuttle go!
oh, i guess i should read what you said..

As far as the windmill idea goes I think most everyone has answered the big stuff. However, there are lots of things within the windmill that would cause energy to be lost. Some examples are the bearings that connect the hub to the blades, the generator that converts the rotating blade into electrical energy, and simply the many billions of particles from the sun that would hit the fan blade in space. The second law of thermodynamics basically says that any useful energy will eventually turn into useless energy. It’s a tough concept to explain but basically things like friction or electrical resistance turn good energy that can potentially move things around (do useful work) into random molecular vibrations (heat). The concept is called entropy.

In an ideal system, friction, resistance, and other things aren’t factored into the analysis; however, no system is actually ideal. Entropy will always increase. This means that there is no system that you can get as much energy out of it as you put in it (especially not more than you put in it).

Thermodynamics is a very interesting subject. The history of its development is also quite interesting and I’d definitely recommend reading some of it.

You could rig your orbital windmill with solar sails, but I think that it would be easier to use solar panels, or else regular groundside windmills.