Aristotelian physics laws of physics". The Persian polymath Abū Rayhān al-Bīrūnī (973-1048) was the first to realize that acceleration is connected with non-uniform motion (as later expressed by Newton's second law of motion). During his debate with Avicenna, al-Biruni also criticized the Aristotelian theory of gravity firstly for denying the existence of levity or gravity in the celestial spheres; and, secondly, for its notion of circular motion being an innate property of the heavenly bodies. In 1121, al-Khazini, in "The Book of the Balance of Wisdom", proposed that the gravity and gravitational potential energy of a body varies depending on its distance
Kepler's laws of planetary motion laws fit the observations better than does the model proposed by Copernicus. Kepler's corrections are not at all obvious: The eccentricity of the orbit of the Earth makes the time from the March equinox to the September equinox, around 186 days, unequal to the time from the September equinox to the March equinox, around 179 days. A diameter would cut the orbit into equal parts, but the plane through the Sun parallel to the equator of the Earth cuts the orbit into two parts with areas in a 186 to 179 ratio, so the eccentricity of the orbit of the