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[Rose]

What would the turbine do?

Any work it's doing would slow it down.

[Execute/Dumbo.exe]

And also I'm pretty sure putting it in zero gravity wouldn't do anything if you assume it's symmetrically built, since gravity would already be working equally on both sides*, the biggest source of friction (Apart from the energy it's using to power whatever you want it to) would just be the air around it.
Even then if you put it in space, it would still be kind of needless because you could just cut out the middleman and power whatever you're powering directly.
*Maybe.

[wierd]

First, we need to define some things.

If you mean this:
Turbine=Spinning Fanlike Thing, but with nothing attached, spinning in a vacuum, in zero G.

Then the "turbine" will spin freely without any disruption.

If you mean this:

Turbine=Device to create electrical energy via moving a permanent magnet around and around inside an induction coil, and is a device that resembles a fan so that the force of a passing fluid (air counts) gets converted into rotation as it passes through friction, which then moves said magnet

Then no.  Even if you spin it around in a vacuum, the induced magnetic field in the coil windings will introduce a magnetic dragging effect, in addition to the losses from resistance of the induced electrical current.

This means that eventually it will stop unless a constant stream of energy is supplied to it, even if all forms of mechanical friction were removed from the shaft.

https://en.wikipedia.org/wiki/Eddy_current

This braking effect is what causes a neodymium magnet to "fall very slowly" when dropped down a copper tube.
https://www.youtube.com/watch?v=5BeFoz3Ypo4

[Osmosis Jones]

In zero gravity, a moving object will stay in motion until it's stopped or slowed by something else, correct? If you were to create a turbine in zero gravity, could you start it spinning very fast using an extremely small amount of thrust, then just let it keep moving on its own inertia until it needs another little bit of thrust to counteract the friction from the brushes?

Lets break it down;

In zero gravity, a moving object will stay in motion until it's stopped or slowed by something else, correct?

Zero gravity AND zero atmosphere, yes. Either on their own, this is not necessarily true, and honestly in this case the atmosphere is the more important issue.

Really, even in zero grav and zero atmo, it's still technically false for anything spinning that doesn't satisfy cylindrical symmetry along the axis of rotation, since gravity waves, but for all practical purposes...

could you start it spinning very fast using an extremely small amount of thrust,

In a vacuum, if it was very light or the thrust was constant for a long time, yes. Acceleration is still a function of both force and mass (which for rotational cases becomes the moment of inertia, i.e. a function of both the mass, AND it's distribution relative to the axis of rotation), so a tiny force won't instantaneously get you up to high speeds, but in a vacuum, the absence of friction would allow such a thing if the force is constant for long enough. Of course, if it's in a vacuum, I'm not sure turbine is the right name for it, since a turbine is an object that generates rotation from the movement of a fluid (be it a gas or a liquid).

then just let it keep moving on its own inertia until it needs another little bit of thrust to counteract the friction from the brushes?

Anything that draws power from the turbine will slow it down; whether that's in the form of atmosphere being moved out of the way, or  brushes causing friction, or the current drawn from it, that will be constantly braking it. Since you specified a tiny thrust, it's quite possible that said braking would be greater than the thrust, and hence it would eventually slow down even under conster thrusting.

HOWEVER, one possibility here is using the turbine as a flywheel instead; note the second case they list. If you got your spinning object up to very high speeds in a vacuum without tapping it, you would then in effect be able to use it as a mechanical battery, tapping it for higher power over shorter time frames.

[Gentlefish]

... How large would a solar wind turbine/water wheel have to be to be an effective energy source?

[Starver]

... How large would a solar wind turbine/water wheel have to be to be an effective energy source?

...to power what, exactly?

(Not that I'm sure that angled vanes in a 'solar wind turbine' would be better than perpendicular ones of like size when coated with photovoltaic cells, in generating power, at any distance from the Sun.  You'd need to attach to a non-rotating/counter-rotating assembly (in the latter case, counter-angled vanes/sails behind connected by an axle) and derive the power by the differences in rotation through a mechanical linkage that is designed, and lubricated, with long-term space-tolerant materials in mind.  I suppose a statite could use the method in isolation to set it spinning for orientation-keeping purposes, but you'd need to de-feather your sails (or at least neutralise, rotation-wise, even if you kept an adjustable chevron-like profile to allow dynamic force-balancing) to prevent rotation of the whole statite to continue to build up to dangerous levels. - But that's just my first thoughts, and maybe I'm missing something about the question, or else some other realistic application.)

[redwallzyl]

MinutePhysics: https://www.youtube.com/watch?v=KRGca_Ya6OM

interesting idea. what do you guys think.

[Criptfeind]

Well, I guess it makes sense. I was hoping that I could find a Wikipedia page or something to see if there are people more qualified then me that have objected to it, but my google powers seem to fail me or such things don't exist.

[TempAcc]

The general idea around the whole ~searching for aliens~ effort is based around what we know of biology, geology, astronomy, chemistry and physics. This is both good and bad. Good because it gives us a good idea on how and where complex organisms can perhaps form, but its bad because it kinda limits our scope to things that fall under the criteria we stablished based on what we observed on earth.

If there are lifeforms out there that are radically different to earth life forms, IE those that may live in radically different environments and under different conditions (which we might consider hostile to life altogheder), then its unlikely we'll ever find them.

WE CAN determine the general trends that favor biological life by looking at our planet, the problem is, what guarantees that we followed the general trend in the development of life in the universe? What if WE are the exception? What if the huge majority of the life forms in the universe are composed of gas beings hundreds of meters in size that communicate by suplexes and reproduce by singing We Are The Champions backwards?

So ye, I think we're doing good so far with the current methodology we developed for searching for signs of alien life, but there's always the unknown factor, but this doesn't mean we're going to run into a race of alien cat girls in the future, obv.

[Sheb]

There are very good reasons to expect life not to work with gas clouds hundred of meters big. Like the fact that you can't really compartimentalize chemical reaction in such a medium.

[TempAcc]

:v it was an intentionaly unrealistic/hyperbolic example, but that assumption is still based on what we know of chemical reactions and physics. Maybe said beings exist on such a thick atmosphere that chemical reactions don't spread their energy all over the place when they happen, or maybe they're gas bags rather then clouds, maybe their metabolism is extremely slow and composed of very minute chemical reactions. My point is, we have a good lead, but hey, who knows? The universe is a pretty big place, and physics/chemistry/biology have proven time and time again to to always have more mysteries in store.

[Sergarr]

It should be noted that any aliens that live in radically different environments, radical enough to avoid being predicted by modern science, will almost certainly live on a cardinally different "clock time" than we do (i.e. they'll either be thousands of times faster than we do at stuff like "thinking", or thousands of times slower, or have otherwise a very erratic and irregular behaviour pattern). In other words, it would be impossible to meaningfully interact with those.

Also, stuff like "material science" ensures that, no matter how they look, the general material structure, shape and functionality of tools they use is going to be pretty similar to those of our own, which would result in similar environmental changes and other observable effects, which would reduce the chances of "incomprehensible tool-using aliens" event happening pretty much down to zero.

[TempAcc]

I stand by my theory that singing We Are The Champions backwards is a viable method of reproduction.

[Descan]

I could certainly see a certain pattern of soundwaves interfering in such a way in certain environments as to create optimal conditions for certain reactions to take place. :V Such as babby makin'.

[TempAcc]

Descan is developing secret technology to touch butts with the power of his voice.