Download Models of the solar system

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MODELS OF THE SOLAR SYSTEM
You are required to "interpret given information about developments in ideas about models of the
Solar System".
In other words - don't memorise this! They'll supply you with all the background material on the
paper, and then ask questions about it.
Sun
Earth
Moon
The Ancient Greeks thought that the Earth was the centre of
the Universe, with the Moon, Sun and a few planets orbiting
around it. The stars were fixed lights on the inside of a large
sphere. Everything went around the Earth. They believed that
the Heavens were perfect and that every shape and motion
should consist of perfect circles.
This Ptolemaic model works pretty well in some regards - it
explains why the Sun and Moon rise and set, and why the stars
move across the sky at night. For centuries, this was the
accepted view of the Solar System.
In 1543, Nicholas Copernicus suggested that the model could be made simpler in some regards if
you put the Sun at the centre of the Universe and allowed the Earth and other planets to orbit around
it. The model gave mathematical predictions that matched observations but it still had problems: in
many ways it was at least as complicated as the Greek model - always worrying.
Meanwhile, astronomers were working hard to obtain better observations of the actual movement of
the planets. Two rather important astronomers, Tycho Brahe and Johannes Kepler, spent years
accumulating accurate observations. Literally years, by the way - Kepler spent eight years observing
Mars.
Moon
Earth
Sun
Kepler used advances in mathematics to show that the
Copernican model became dramatically simpler if you
assumed that the planets had slightly elliptical orbits (first
laws published in 1609). Suddenly, the model becomes
straightforward, elegant and gives very accurate predictions
that are then borne out by observations.
Galilei Galileo used the newly invented telescope to
examine the Heavens. He saw a variety of odd phenomena, including mountains on the Moon
(imperfect Heavens) and moons orbiting Jupiter (so not everything orbits us!). Galileo started to teach
the Copernican heresy and published a booklet about it in 1632, but (due to his own political stupidity)
got into a lot of trouble and was banned from teaching it again.
In 1686 Sir Isaac Newton publishes a book in which he proposes a number of laws of motion and
gravity. He invented some even more advanced mathematics (calculus) to show that his laws
automatically lead to elliptical orbits, providing a theoretical basis for Kepler's model.
And the relevance of this? The advances that occurred were stimulated by various things:
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The search for simple, elegant models. In Physics, messy and complicated is usually wrong.
Improved and extended observations, to which the predictions of models could be compared.
Advances in technology - the telescope greatly improved the accuracy of observations and
allowed new types of observations to be made.
The spread of ideas. The growth of printing enabled large numbers of books to be produced.
Kepler and Galileo had read the work of Copernicus, rather than having to start from scratch.
Advances in our understanding of the natural world - Newton's laws give a theoretical basis for
previously purely mathematical models.
Advances in mathematics - neither Kepler nor Newton could have developed their theories
with the mathematics available to Copernicus.