Theoretically, one could envisage a universe with only 2 particles orbiting around each other....perpetually
in space it is totaly possible, but on earth i dont think so because gravity will always have a downward pull, in-time stopping the movement. peace.
Yes, but as I explained earlier, that is not the kind of perpetual motion that is prohibited by the second law of thermodynamics. It prohibits, among other things, perpetual motion machines.
Theoretically, one could envisage a universe with only 2 particles orbiting around each other....perpetually True but one could also envision something similar to David Hillard's Grand Hotel but that doesn't mean that it is possible
"orbiting around each other" You clearly assume that they gravitationally attract each other, but are forgetting that they lose enegy and spiral together due to the gravitational wave radiation energy losses, assuming current phsics of this is correct.
Yes. In fact, there are many similar things that could be called "perpetual motion" - for example an electron in a hydrogen atom will theoretically "orbit" the nucleus forever. But when people talk about perpetual motion, and perpetual motion machines in particular, they mean real, macroscopic devices that never run down, or devices for which the energy output is more than the energy input (so-called "over-unity devices"). This is the kind of perpetual motion that defies the laws of physics (thermodynamics).
A site where some of the better perpetual motion machine designs are collected in one place, for comparison: http://www.lhup.edu/~dsimanek/museum/unwork.htm