Isaac Newton (25 December 1642 – 31 March 1727) is credited with introducing the idea that the motion of objects in the heavens, such as planets, the Sun, and the Moon, and the motion of objects on the ground, like cannon balls and falling apples, could be described by the same set of physical laws. In this sense he unified celestial and terrestrial dynamics. Using his law of gravity, Newton confirmed Kepler's Laws for elliptical orbits by deriving them from the gravitational two-body problem, which Newton included in his epochal Principia.