Who Was Galileo Galilei and Why Is the Italian Astronomer the Father of Modern Observational Astronomy?

Galileo Galilei seemed to be larger than life.

Born in Pisa, Italy, in 1564, at the culmination of the Renaissance, Galileo was not just the first person to focus a telescope on the stars; he also turned the view of the world upside down.

Galileo was a master of astronomy, mathematics, physics, philosophy, and publicity. His image, and probably the reality, was that of a temperamental genius: brilliant and witty, but also caustic and nasty.

Prominent people sought his company, until he took up the unpopular and dangerous task of defending Copernicus’s sun-centered view of the solar system in his published works.

We accept as fact that the Sun is the center of the solar system. Imagine, however, knowing just as surely that Earth is the center. We might have said: “Everyone knows that the Sun revolves around the Earth. Only a few crazy scientists think otherwise.”

In 1543, Nicolaus Copernicus had published his treatise proposing that all the planets, including Earth, revolved around the Sun.

This breakthrough was welcomed by a few, but only in private, because the most powerful government in Europe at that time, the Roman Catholic Church, had a vested interest in the status quo. Its whole system of beliefs, and its authority, rested on Earth being central to the universe.

Galileo’s public support of the Copernican worldview upset the church. Its leaders had dealt with other heretics by ignoring them or burning them at the stake. But the church could not ignore Galileo.

In 1634, Galileo was brought before the church courts and told to recant his heretical beliefs about the solar system.

Faced with the alternative, torture and death, Galileo finally gave in. According to legend, as he left the courtroom, Galileo claimed, under his breath, that regardless of what he was forced to say, Earth still moved around the Sun.

Galileo was under house arrest for the remainder of his life, until 1642.

The church officially accepted the Copernican model of the solar system 350 years later, in 1992.