Today, the 15th February is Galileo Galilei’s birthday. He is often referred to as the farther of modern physics. He is of course also know for his discoveries using his telescope including the Galilean Moons of Jupiter, the rings of Saturn, the phases of Venus many geographical features of the Moon. Galileo as born on the 15th February 1564 in Pisa, Italy.

His legacy for theoretical physics
Galileo’s legacy for physics was his blend of mathematics with experimentation. Most of the contemporary science at the time was rather qualitative and Galileo was one of the first to believe that the laws of nature can take a mathematical form.

Link
Galileo Galilei Wikipedia.