Galileo Galilei & Astronomy

Galileo Galilei was born on February 15, 1564, in Italy. He was an Italian natural philosopher, astronomer, and mathematician who made important contributions to the sciences of motion, astronomy, the strength of materials, and the scientific method's development. He has been called by many names because of this contribution in multiple fields like "father of observational astronomy", the "father of modern physics", the "father of the scientific method", and the "father of modern science".

Galileo was born in Pisa, Tuscany, on February 15, 1564, the oldest son of Vincenzo Galilei (a prominent musician at the time). The family then moved to Florence in the early 1570s, where they had lived for many generations. There he attended the monastery school at Vallombrosa, and then in 1581 went to the University of Pisa, to study medicine.

However, he went against his father's wishes and decided to make mathematical subjects and philosophy his profession. In 1585, he left the university without getting his degree and started to give private classes for mathematical subjects in Florence and Siena. During this, he also designed a new form of hydrostatic balance for weighing small quantities and also wrote a short treatise, La bilancetta (“The Little Balance”), which was circulated in manuscript form. He also began his studies on motion, which he pursued steadily for the next 20 years.

Galileo’s career took a 180-degree turn in the spring of 1609. He heard of an instrument that had been invented that could show distant things as if they were nearby. By trial and error, he found out the key of the invention and made his three-powered spyglass from lenses purchasable in spectacle makers’ shops. What set Galileo apart was that he understood quickly and found ways to improve the instrument, taught himself the art of lens grinding, and produced increasingly powerful telescopes.

In the fall of 1609, Galileo began observing the sky with instruments that could magnify the objects up to 20 times. In December he drew the Moon’s phases as observed through the telescope, showing that the Moon’s surface is not smooth, as previously thought, but is rough and uneven. In January of the next year, he discovered four moons revolving around Jupiter.
His discoveries were earth-shaking and he wrote a book, Sidereus Nuncius (The Sidereal Messenger), in which he described them. Galileo was now a courtier and lived his life as a gentleman.