The world’s first astronomer and the father of modern physics — these are just some of the ways people describe Galileo Galilei.
Early in his career, in 1589, Galileo showed that when two objects are dropped from the same height, they’ll fall at the same speed, regardless of their weight.
He invented the basic thermometer in 1593 and improved many scientific instruments, including the telescope, the compass and the microscope.
In 1609, Galileo’s observations changed how people thought of the Moon. Other people had seen shadows on the Moon, but Galileo realized these were actually mountains and craters. That meant the Moon wasn’t a perfect sphere, as people thought, but rough and cratered, like the Earth.
The next year, Galileo discovered four of Jupiter’s moons and realized they orbited Jupiter. That confirmed what Nicolaus Copernicus had said — that the planets and stars didn’t revolve around the Earth. Galileo’s later observations of how Venus moved were more proof.
Leaders in the Catholic Church felt Galileo’s theories went against the Bible. For this “crime,” Galileo spent the last nine years of his life confined to his house.
Today, most people agree with famous physicist Stephen Hawking, who said, “Galileo, perhaps more than any other single person, was responsible for the birth of modern science.”