Excuse me if ninjaed, but there's nothing on this particular page of replies that I can see.
Perpetual motion needs the further study of gravity and it's effect on dark matter.
Dark Matter (unproven, but a hypothetical answer to some universal puzzles) is essentially matter that cannot be 'seen' (detected) by any other means than its gravitational influence. The whole point is that Dark Matter reacts 'normally' to gravity, just not normally to electromagnetism/whatever.. At least in ways that we can currently detect, from such a distance (or in the smallest quantities which it can only exist in if it's anywhere around/on/in our own planet.
Perpetual motion, on the other hand, has to do with conservation of energy (and mass), entropy, the impossibility of 100+% efficient systems and numerous other complaints. If I were looking for a viable PM device, I'd have to be looking at some way of separating inertial and gravitational mass values, on demand, or throughout a region of space, without needing to expend more energy as could be obtained from such a system in generating that effect.
The alternative method of putting a wormhole 'exit' above the wormhole 'entrance' and dropping stuff straight through it would doubtless involve either massive expenditure of effort to maintain the wormhole or
cause such large amounts of energy feedback[1] that it forces the system to collapse/never have been viable in the first place.
There was a thesis I wrote a while ago about a planet orbiting around a sun and being pulled 'back' by a secondary distant sun thus remaining in permanent orbit until something disturbs it, but I appeared to have misplaced it.
If you aren't talking about a
Lagrange Point situation, I think you've got something wrong, in that scenario.
(I.e. when you mean 'orbiting', you mean like Earth being at an Earth-like distance, but not actually rotating around the Sun, but instead being held off by the second Sun? If that second sun isn't itself orbiting around the first (or, rather, they are both orbiting about their common barycentre) then the two suns are going to be 'falling' towards each other. Unless you have other suns either side to balance them, but they need
other suns to balance them, etc... Barring a wrap-around universe (subject to just a tiny offset of any of its components, or else it'll end up collapsing together anyway) you're in big cosmological trouble!_
Also: space. Just think of a turbine that doesn't stop because there isn't any large force of gravity and air friction. Only problem is it moves in one direction :/ Still, it's damn well close enough for anything we need.
Why do we need an eternally spinning turbine (or any other object, like spanners, pencils, footballs,...)? The moment we try and get any power out of it, it'll no longer be eternally spinning, for a start. (By the way, it would only not stop spinning if there was
no friction, not "no large amount of". Gravity just dictates where it's falling to, and you could always arrange for it to orbit something forever, as long as you also stopped passing dust and gas from entering orbit around the same object and providing the small amounts of friction you're being too blasé about...)
Anyway, probably way ninjaed. Or we're now talking about Magma.
[1] By dragging one end of the wormhole around, you would at least introduce a tiny but still present time-displacement between the two ends, radiation entering the 'younger' end would come out of the 'older' one slightly before it entered, and potentially re-enter the younger end again. Given the distortions of space around the wormhole ends there'll probably not be any actual time-travel effects[2], but it would cause problems nonetheless.
[2]
If later radiation can re-entering the system at an earlier time, it can only go back so far and it can't go back to before the system has been so if it absultely
insists on perpetually time-travelling, it'll be by diminishing returns... Probably until it lessens to such an extent that the trip across the intervening gap wastes the time 'gained', but that would mean that any sustained 'ray' of radiation builds over itself, simultaneously... Personally, I think tha tthe universe wouldn't allow that, but it's a tad theoretical at the best of times, so I won't proscribe any possibilities, there.