Solar system formation simulation

Here's a good simulation of how many think the solar system formed, using Newton's law of gravity primarily. The results of such simulations agree quite well with the actual structure we see today, which is why scientists use simulations. Simulations use the mathematical models and theories, use those equations to calculate what our theories suggest should happen in reality, and then test the simulation by comparing it to reality. When simulations match reality, of course this provides confidence that the theory being tested is certainly on the right track and gives us a set of ideas for how Nature really works.