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Since people first looked up and wondered what the lights in the
sky were, we have tried to solve the mysteries of the stars and
planets. Mathematics has always been a powerful tool for studying,
measuring and calculating the movements of the planets. So
mathematics was used to both discover, then prove the first basic
`rule' of our planets - that they travel around the sun, not around
Earth. In the 1500's and 1600's, now famous men such as Nicolaus
Koppernik (

Copernicus ), Isaac Newton and

Galileo Galilei worked hard to convince the authorities of this
truth.

Between 1609 and 1618

Johannes
Kepler announced his laws of planetary motion. Using the
careful observations recorded by

Tycho Brahe , he showed that the shape of a planet's path
around the sun (orbit) was an ellipse (almost a circle). He
calculated the speed that each planet travelled. He also worked out
the relation between size of the orbit and the time it takes for
the planet to go once around the sun (revolution).

Later,

Isaac Newton used some different mathematics to develop the
theory of planetary motion in terms the effects of gravity.
However, the planets Uranus, Neptune and Pluto had not yet been
discovered.

### Eclipse of the Sun

Perhaps you have heard about total eclipses of the sun? People
in different parts of the world will see different amounts of the
sun blocked as the moon passes between the Earth and the sun. Long
ago, people were terrified by eclipses because they didn't know
when they would happen or what caused them. Scientists are able to
predict all of this through the use of mathematics. To find out
more about eclipses and the sun visit

The
Dynamic Sun .