Galileo, Copernicus and the heliocentric model
Although scientists as early as Aristarchus of Samos knew the relationship between the sun and earth around 270 BCE, it wasn’t until 1543 that Nicholas Copernicus (born on February 19, 1473) published his masterwork De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published the same year that he died that the heliocentric model received wide distribution. Perhaps his death and inability to defend his thesis led to the very slow spread and adoption of his idea, so that by the year 1616 a group of cardinals and bishops under the direction of the Vatican met to denounce Galileo Galilei, who was using the results of his observations made with the new technology of the telescope to re-introduce the heliocentric model of the solar system.
A decade and half passed before Galileo was dangerous enough to draw a trial, which commenced in 1633. Galileo was furious with the philosophers, theologians and scientists who denounced his idea, complaining to his friend and fellow astronomer Johannes Kepler,
My dear Kepler, I wish that we might laugh at the remarkable stupidity of the common herd. What do you have to say about the principal philosophers of this academy who are filled with the stubbornness of an asp and do not want to look at either the planets, the moon or the telescope, even though I have freely and deliberately offered them the opportunity a thousand times? Truly, just as the asp stops its ears, so do these philosophers shut their eyes to the light of truth.
He lost the trial and spent his last eight years under house arrest, working on his theories from his home in Pisa.
The word heliocentric comes from Ancient Greek, a combination of the words ἥλιος (helios) meaning sun and κέντρον (kentron) meaning center. It would take another three centuries for scientists to understand that not only is the Earth not the center of the Universe, neither is the Sun.
Painting of Galileo Facing the Roman Inquisition by Cristiano Banti, 1857, in the public domain.
Image from Copernicus in the public domain.