Where did earth came from?

Answer 1

Earth is a conglomeration of debris that was orbiting the sun shortly after the sun formed. Most of the pieces were either already in or close to earth's current orbit, as earth grew larger from collision after collision it swept up this material. The moon was formed when a shallow glancing collision with an object roughly the size of mars collided with earth, scooping out a chunk of mantle which merged with the object and went into orbit. Most of earth water and atmosphere probably came from very late collisions with comets.

Then for people of faith, there is Creationism.