1. The History of Astronomy
Part 5
Copernicus

2. “the simplest explanation is usually best.”
Copernicus ( )
Copernicus was a Polish
physician, lawyer and astronomer,
he questioned the Ptolemaic System.
It just didn’t pass the test of “Ockham’s Razor” that
“the simplest explanation is usually best.”

3. The Copernican System
Copernicus proposed a simple heliocentric system with circular orbits
The planets orbit in the right order (though without Uranus and Neptune).
He even got the relative distances from the sun correct (see chart on page 49).
Moon orbits Earth
To avoid religious persecution he published his work
“de revolutionibus orbium coelestium” posthumusly.

4. This system explains retrograde motion easily,
The Earth was simply passing by!

5. The lack of observable parallax could be explained with simple geometry.
A star far enough away would have a parallax too small to see
Recent discoveries had shown that stars might be far enough away (see Tycho)

6. At first Copernicus's Simple Heliocentric model met opposition from great astronomers such as Tycho Brahe .
But some agreed,
Like: The Astronomer Kepler
And the mathematician/philosopher: Rene Descartes
A Great Debate ensued

7. Crazy Talk! Thomas Diggs and Giordano Bruno both proposed that:
Stars are other Suns and planets may orbit them!