The Birth of A New Physics

Aristotle, Ptolemy, Copernicus, Kepler, Galileo, Newton.

I've been enjoying my reading on the history of science very much in the past month. I like to connect the ideas which I've studied previously with the people who created them. These people are much more impressive when their context is applied to them. There is something about Tycho Brahe which endears him to me (though he wasn't discussed much in this work). Kepler was supersticious -- he practiced astrology and his model of the universe was dearer to him than his three famous laws. Galileo seemed to me to be the most scienfic of all his peers, Newton seemed the most mathematical. Aristotle's model was so complete that it took nearly twenty five hundred years to completely overthrow his ideas.

Kepler's Laws-
The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)

An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)

The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

Newton's Laws-
Every object in a state of uniform motion tends to remain in that state of motion unless an extermal force is applied to it. (The Law of Inertia)

The acceleration of a body is parallel and directly proportional to the net force acting on the body, is in the direction of the net force, and is inversely proportional to the mass of the body, (F = ma)

When a first body exerts a force on a second body, the second body simultaneously exerts a force on the first body. This means that F₁ and F₂ are equal in magnitude and opposite in direction.