Just as early man would slowly discover the land "just over the mountain", so has modern man furthered our knowledge of the Sol system. First we were at its center, then the church allowed us to orbit the sun--how gracious of them. We knew of 5 planets in the solar system along with our own, and then we knew 6, 7, and then 8. Pluto came last, closely followed by the now debunked Planet-X.
