Johannes Kepler

“Astronomia

Nova”

Title PageAstronomia

Nova

Note the Greek:

“Aitiologitos”

Kepler’s view of the Solar System

(from Mysterium Cosmographicum)

Outermost is ‘sphere

of Saturn’

It has a cube inscribed

within it

Inside the cube is the

sphere of Jupiter

It has a tetrahedron

inscribed within it

Inside is the sphere of

Mars

Etc.

(NB: this model is for

the Copernican

system!)

First Law:

Law of Ellipses

One of the foci is

the Sun

What about the

other one?!

Second Law:

Law of Areas

3 months at

Aphelion

will trace

out the

same area

as 3 months

at

Perihelion

A Bit of Taxonomy

Bisected

portion of the

Major Axis is

the “Semi-

Major Axis”

We’ll need

this for the

next law

Third Law:

Law of Harmony

The law states that:

The ratio of the square

of the revolutionary

period for every planet

is equal to the ratio of

the cubes of the semi

major axes

HUNH?

In other words, there

is a precise correlation

between the sidereal

period (squared) and

the average distance

from the sun (cubed)

and it is the same for

every planet!