Search results
Results from the WOW.Com Content Network
In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler in 1609 (except the third law, which was fully published in 1619), describe the orbits of planets around the Sun. These laws replaced circular orbits and epicycles in the heliocentric theory of Nicolaus Copernicus with elliptical orbits and explained how planetary ...
Aristotle proposed a geocentric model of the universe in De Caelo. The Earth is the center of motion of the universe, with circular motion being perfect because Earth was at the center of it. There can be only one center of the universe, and as a result there are no other inhabited worlds within it besides Earth.
Solving applications dealing with non-uniform circular motion involves force analysis. With a uniform circular motion, the only force acting upon an object traveling in a circle is the centripetal force. In a non-uniform circular motion, there are additional forces acting on the object due to a non-zero tangential acceleration.
Other Greek scientists, such as the Pythagorean philosopher Philolaus, postulated (according to Stobaeus' account) that at the center of the universe was a "central fire" around which the Earth, Sun, Moon and planets revolved in uniform circular motion. [195]
1) the circular motion of the celestial bodies produces a sound; 2) the loudness of the sound is proportional to their speed and magnitude (according to Achytas, the loudness and pitch of the sound depends on the force with which it is produced; 3) the velocities of the celestial bodies, being proportional to their distances from the earth ...
The first non-geocentric model of the universe was proposed by the Pythagorean philosopher Philolaus (d. 390 BC), who taught that at the center of the universe was a "central fire", around which the Earth, Sun, Moon and planets revolved in uniform circular motion.
The uniformity was generally assumed to be observed from the center of the deferent, and since that happens at only one point, only non-uniform motion is observed from any other point. Ptolemy displaced the observation point from the center of the deferent to the equant point. This can be seen as violating the axiom of uniform circular motion.
According to the accepted Aristotelian physics of the time, the heavens (whose motions and cycles were continuous and unending) were made of "Aether" or "Quintessence"; this substance, not found on Earth, was light, strong, and unchanging, and its natural state was circular motion. By contrast, the Earth (where objects seem to have motion only ...