47.

"Look round at the courses of the stars, as if thou wert going along with them; and constantly consider the changes of the elements into one another; for such thoughts purge away the filth of the terrene life."

This is my favorite of Aurelius' passages in "The Meditation". To me it means that life is constantly changes and effecting itself. It talks about the galaxy and it's movement. The galaxy is in constant ever changing motion just like life. The collision, combination, explosion and growth of stars is remarkable and spontaneous. Just like every instance of life, good or bad.