The human mind has a problem, it cannot imagine limitless. There has to be a barrier or a horizon or an event. Even learned professors discussing space seem to be uncomfortable with that and they speak of the universe as if it were finite . But is that true ? Limitless means it will never end regardless of the direction you take. The same with physics, we know the physics applicable to near space. It does not follow when you use the term 'limitless' that the physics we know will be the same everywhere, but here again the human mind will not permit us to speculate . To us everything has length, breadth, and width, or we can touch it, hear it, or see it. If it fails to fall into any of those categories it cannot exist ….or can it ?