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Aristotle introduced his theory of how comets came to be by first stating that the world was divided into two parts: the earth and the heavens. The upper parts of the earth, below the moon contained phenomena such as the milky way and comets. These phenomena were created from a mixture of four elements that were naturally found on earth: water, earth, fire, and air. He theorized that the earth was the center of the universe, which was surrounded by various other planets and stars. The universe or better known as the heavens filled the void above the terrestrial atmosphere with a fifth element called "Aether." Aristotle believed that comets were shooting stars that evolved into something much different. This proved that comets came from a combination of the elements found on earth. Comets could not have come from the heavens as the heavens are never-changing but comets are ever-changing as they move through space. Anaxagoras and Democritus’ theory deviated from Aristotle’s, as they believed comets were only after-images or shadows from planetary eclipses. Pythagoreans claimed comets were planets that revolved around the sun for a longer period of time across the edge of the sun. Hippocrates of Chios and Aeschylus had a similar belief to the Pythagoreans, as they both believed comets were planets that had special properties. Chios and Aeschylus theorized that comets are planets that have an immaterial tail produced by the atmosphere.

Aristotle’s theory over the creation and properties of a comet was prevalent up until the 1600s. Many philosophers and astrologers came up with their own theories to try and explain the phenomena that is a comet but only two were of relevance. Aristotle’s theory still prevailed, along with Seneca’s. However, Seneca believed comets came from the celestial region of the universe. He firmly opposed Aristotle’s theory that comets were formed from the element of fire by stating the comets fire would grow if it ever entered the lower depths of the atmosphere. Seneca recognized the flaws in his theory as he understood that accurately and consistently observing a comet had a high level of difficulty.

In the mid 1500s, a mathematician by the name of Jean Pena opposed Aristotle’s theory of comets by studying the physics and math behind the phenomena. He deduced that a comet maintained its visual appearance, regardless of the view and angle in which is observed near the horizon or the sun. Pena argued that the orientation and appearance of the comets were due to the physics of space. Pena claimed comets were at a farther distance from the earth than the moon as it would pass the moon at a greater speed, due to the effects of earth’s gravity. The tail of a comet points directly away from the sun as it is moving through space, because the sun's rays are focussed through the comet's body, which acts as a lens based on the laws of refraction. The comet’s tail is composed of an air-like element that is transparent as it is seen in space but only when it is faced away from the sun. The explanation on how we are able to visually see the tail is due to the solar rays that the sun is reflecting off of the tail. The Laws of Refraction allows the human eye to visually see the tail of a comet in space at a different position than it truly is because of the reflection from the sun.

The theories that astrologers and philosophers before the 1600s came up were still prevalent by the time Isaac Newton began studying mathematics and physics. John Flamsteed, one of the leading astronomer in the Newtonian age revised Descartes' theory to prove that comets were planets. The motion of the comets came from magnetic and vortex particle forces, and the tails of the comets were physical not just a reflection. Flamsteed's revision contradicted Aristotle and many other comet theories as they believed that comets came from earth and had their own special properties from the rest of the phenomena in space. However, Newton rejected Flamsteed's revision of this theory. Newton theorized that the properties of these phenomena were not due to magnetic forces because magnetic forces lose their effect with heat. Newton finalized his study of comets when he revised Flamsteed's theory that a comet's motion was due to a force acting upon it. Isaac Newton believed that the motion of comets came from an attracting force, which came from either the natural effects of the sun or a different phenomenon. Newton's discovery over the comets motion propelled the overall study of comets as a part of the heavens.