Welcome to practical physicsPracticle physics - practical activities designed for use in the classroom with 11 to 19 year olds

Planets in the Copernican system

Copernicus did not only offer an alternative model that looked simpler than the heliocentric model. He also extracted new information from his heliocentric scheme: the order and relative sizes of the planetary orbits.

But he did not know the real values of planets' orbit radii. For that he needed an accurate measurement of one of the distances. All he had was a Greek measurement of the distance of the Earth from the Sun. 
Estimating the size of the planets themselves would have to wait until telescopes had been invented. A rough model of the solar system known to Copernicus would then be: 
Sun - beach ball 
Mercury - a grain of sand, 16m from the Sun 
Venus - a pea, 29m from the Sun 
Earth - a pea, 40m from the Sun 
Mars - an apple pip, 61m from the Sun 
Jupiter - a ping pong ball, 210m from the Sun 
Saturn - a ping pong ball, 380m from the Sun 
Download modern data to make a chart of the planets known to Copernicus.


Cookie Settings