Happy Birthday Copernicus!

Today is the 543rd birthday of Nicolaus Copernicus.
He was a Renaissance mathematician and astronomer who formulated a model of the universe that placed the Sun rather than the Earth at the centre of the universe.
Born: February 19, 1473, Toruń, Polan
Died: May 24, 1543, Frombork, Poland
To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.
Mathematics is written for mathematicians.
For it is the duty of an astronomer to compose the history of the celestial motions through careful and expert study.