Galileo was one of the first modern scientists.
He was born in Pisa, Italy, in 1564.
At first he studied philosophy,
but later he studied mathematics and astronomy.
He was interested in the way the earth and other planets move around the sun.
He found out several important facts about our world.
He also started the new way of working in science.
Before Galileo, scientists did not do experiments.
They just guessed about how something happened. Galileo was different.
He did not just make guesses.
He did experiments and watched to see what happened.