There's a software that make you able to simulate movements of celestial bodies, called
Universe Sandbox. I tried it out, made some simulation about what happen if a large cluster of moon-sized bodies are left to undergo a gravitational collapse on their own. Would they eventually form a massive object in the center and have planets orbit in beautiful near-perfect circles in a plane?
The result was not close the perfection of the solar system. While a massive object in the center formed, the remaining bodies either move in highly eccentric orbits, or have too high velocity to stay in the system. In addition, they have no tendency to align in a plane. Life in such solar system would be impossible. And contrary to popular belief, eccentric orbits do not magically become circular over time.
The only reasonable explanation is that God created the sun, earth, moon and all planets, and placed them in proper orbits, at proper velocity.