A life of research
Born in Toruń, he studied in Poland and Italy. As a canon in Frombork, he divided his time between administration, medicine and astronomical calculation.
He developed his model over several decades. His major work, De revolutionibus orbium coelestium, appeared in 1543, the year of his death.
Understanding the contribution
In his system, Earth rotates daily and travels around the Sun annually. The apparent backward motion of planets becomes largely an effect of our own moving viewpoint.
He nevertheless retained circular motions and epicycles: this was not yet Kepler’s model. Nor did the model by itself provide observational proof that Earth moves.