What is Perpetual Motion?
A perpetual motion machine is (as the name implies) a machine that moves perpetually; it never stops. Ever. So if you created one today and set it going, it would keep on going until the Big Freeze. Calling that “a long time” is an understatement of epic proportions.
If you aren’t aware, the Big Freeze is the theoretical end of, well, everything. It is the point at which the universe has expanded so much that it reaches a state of zero thermodynamic free energy. In other words, it is the point at which the cosmos, as a whole, will be unable to sustain motion. All of spacetime will be at absolute zero (the coldest known temperature, where all movement stops).
There are many designs on the internet that claim to be working designs for perpetual motion machines. If you look at those designs, it’s not too farfetched to think that some of those machines could (if engineered correctly) move without stopping. And if we could do this, the implications would be staggering. We would essentially have an eternal source of energy. More than that, it would be free energy.
Unfortunately, thanks to the fundamental physics of our universe, perpetual motion machines are impossible.
Now, I know that there are probably a lot of people who are saying, “You should never say ‘never’ in science.” And fair enough. I admit that new knowledge could come along; however, in order for perpetual motion machines to be possible, this new knowledge would have to break physics as we know it. We’d be wrong about simply everything, and nearly none of our observations would make any sense.