The motion was for a very long (and sometimes still is) a sort of Holy Grail of the inventor, as the transmutation of metals was among alchemists. 

The idea is simple: what if someone invented one day a kind of universal motor, which would alone any moving mechanism, in short, which could supply energy at will? This would certainly be the inventor for eternal glory ... 

But it seems that the existence of such a machine would contradict the laws of classical physics, especially one of the most basic laws of physics: the conservation of energy, which is found naturally in thermodynamics (the science that was originally invented precisely to study the machinery - steam, in fact), but also mechanics, relativity and quantum mechanics! 

Indeed, it is said that energy is what is called a quantity, we will say "something" that is preserved: this means that it carries, it turns, but never that, but then she never comes out of nowhere. 

The energy contained in our muscles is that we eat. What we eat has to be other animals that eat plants or plant directly, which are a form of energy. This energy comes in fact from sunlight, which in turn derives its energy from nuclear reactions taking place within it. In short: it never fails to draw energy from nowhere. If you take an object, whatever it is, even if the uranium that runs nuclear power plants, it contains a finite amount of energy. 

Imagine that there may be a machine, a classical mechanics capable of providing energy at will is pure utopia. This is called a perpetual motion of the first kind, because there is another type of perpetual motion, and because it would undermine one of the principles of physics the more established, the first principle of thermodynamics. 

I recently saw a television broadcast on a large public network, an evening of listening, which praised the invention of an enlightened: he built a machine that never stops! The perpetual motion! And we explained that he had seriously lucky that it fell on him, and he built a museum (!) Of motion (which incidentally, did not look having been able to operate more than two hours). It would seem that no one had thought to warn that such fads (relatively common since found a lot of machines on the internet that produce energy but-n-that-never-have-been-built - lack-of-sub) was increased from fashion since the discovery of the laws of thermodynamics! And without necessarily being insane, the paper in question was hardly aware of physical theories - in any case hardly believe ...