The physics we know today have been applied to almost anything and have not proven faulty, but these laws have only been applied to things in our own knowledge. If the laws of physics are different in other areas, what things would need to change for that to happen?

I think really your question isthis: do the laws of physics apply everywhere in the universe in the same way as they do here on Earth? For example, does Newton's 3rd Law apply on the surface of Pluto? In reality no one truly knows, as no one has been to Pluto to check. However, to date there is no evidence that uniformity is not the case, and so scientists have a belief that the universe behaves in a consistent way everywhere. And the fact that we can send probes out past Pluto without them veering wildly off course and the electronic systems on board operate as expected gives credence to this belief - at least as far as the laws of physics applies within our own solar system. Hence we assume that these same laws apply in other soilar systems, and in other galaxies. Observations of stars and galaxies lend credence to this belief, as to date the behavior of stars and galaxies seems pretty consistent no matter which way you look. But this is truly something that can not be proven.