<P> In the 4th century BC , the Greek philosopher Aristotle believed that there is no effect or motion without a cause . The cause of the downward motion of heavy bodies , such as the element earth , was related to their nature , which caused them to move downward toward the center of the universe , which was their natural place . Conversely , light bodies such as the element fire , move by their nature upward toward the inner surface of the sphere of the Moon . Thus in Aristotle 's system heavy bodies are not attracted to the earth by an external force of gravity , but tend toward the center of the universe because of an inner gravitas or heaviness . </P>
<P> In the 4th century BC , the Greek philosopher Aristotle believed that there is no effect or motion without a cause . The cause of the downward motion of heavy bodies , such as the element earth , was related to their nature , which caused them to move downward toward the center of the universe , which was their natural place . Conversely , light bodies such as the element fire , move by their nature upward toward the inner surface of the sphere of the Moon . Thus in Aristotle 's system heavy bodies are not attracted to the earth by an external force of gravity , but tend toward the center of the universe because of an inner gravitas or heaviness . </P>
who came up with the idea of gravity
who came up with the idea of gravity
Aristotle
Aristotle