A History of Astronomy

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Kepler’s work provided one of the foundations for Isaac Newton's theory of universal gravitation

He discovered that orbits are shaped like ellipses, not circles

Slide 9

Galileo Galilei (1564 - 1642)

He discovered the four largest moons of Jupiter and craters on the Moon

His 1631 book, Dialogue Concerning the Two Chief World Systems, argued for the heliocentric model

He said the Earth could be moving because of the law of inertia

Slide 10

Isaac Newton (1642 - 1727)

Newton used the ideas of Copernicus, Galileo, and others and created the 3 Laws of Motion and the Law of Universal Gravitation

These laws accurately described the motions of all objects everywhere, including astronomical objects

Before this it was believed that astronomical objects had different laws of motion than objects on the Earth

Published his theories in his work Principia in 1687