In other words, it is the moment at which the whole universe would be incapable of maintaining motion. It is the point at which the universe has extended to the point of having no thermodynamic free space. That is an understatement of monumental proportions to call it 'a long time.' The Big Freeze is the theoretical end of everything. So, if you started one today and left it running, it will run until the Big Freeze. A perpetual motion machine as the name suggests, a machine that never stops moving. A perpetual motion machine is a machine that can do work infinitely without an external energy source. Perpetual motion is the motion of bodies in an unaffected environment that lasts indefinitely.
