““Kepler’s third or harmonic law states that the squares of the periods of the planets (the times for them to complete one orbit) are proportional to the cubes of their average distance from the Sun; the more distant the planet, the more slowly it moves, but according to a precise mathematical law: P2 = a3, where P represents the period of revolution of the planet about the Sun, measured in years, and a the distance of the planet from the Sun measured in “astronomical units.””
![“[ When a religious couple wrote to Sagan about fulfilled prophecies, he wrote back in May 1996 :] If ‘fulfilled prophecy’ is your criterion, why do you not believe in materialistic science, which has an unparalleled record of fulfilled prophecy? Consider, for example, eclipses.” quote by Carl Sagan](https://sms4smile.com/quotes/img-quotes/875/carl-sagan-160_belief_when-a-religious-couple-wrote-to-sagan-a_25095.jpg)
