Galileo Galilei
and
His Discoveries
Scientific Method:
Galileo Galilei, the founder of scientific method, was an Italian astronomer, mathematician, and a natural philosopher. He made fundamental contributions to the science of motion, especially the motion of bodies in constant acceleration. His discoveries were based on experimental results, and his inferences were expressed in mathematics rather than qualitative narratives.
For instance, he formulated the ‘time squared’ law which says that the vertical distance covered in a free fall is proportional to the square of time. The equation below is what we use today.
He also showed that the projectile motion was parabolic.
Leaning Tower Experiment
Aristotle, the Greek philosopher, claimed that heavier body would fall faster than the lighter one. No one questioned the claim for almost 2000 years. As a proponent of scientific method, Galileo decided to verify Aristotle’s claim.
Legend goes that Galileo performed an experiment by dropping two cannon balls of different masses from the leaning tower of Pisa in 1591. As his equation predicted, both the cannon balls reached the ground at the same time. With this simple experiment, the master of scientific method demonstrated that Aristotle’s claim was not correct.
Astronomy
Galileo's Telescope
Though Galileo did not invent telescope, he made substantial improvements to the idea of telescope that came from Netherlands. His brilliance was on display when he turned his improved telescope to the sky. He made the following stunning discoveries looking at the sky through his telescope.
- The Moon’s surface is not smooth as preached by scriptures and, in fact, it has mountains and valleys.
- There are four moons orbiting Jupiter. These moons of Jupiter are now called Galilean moons.
- Venus too undergoes phases just like our Moon.
- There are sunspots on the Sun.
- There are rings around Saturn .
- The sky is filled with many more stars than the naked eye can see.
Copernicanism
The above discoveries, especially the discovery of moons orbiting Jupiter and the discovery of phases of Venus, convinced Galileo that Copernicus’ heliocentric theory of the solar system was right, and Ptolemy’s geocentric theory was not right.
Besides, geocentric theory could not explain the retrograde motion of the planets; it had to use complicated epicycles over epicycles to account for the retrograde motion.
However, his support for heliocentric theory, unfortunately, put him at odds with religious doctrines.
The church considered his book “Dialogue Concerning the Two Chief World System, Ptolemaic & Copernican,” published in 1632, heretic. In 1633, the inquisition of the church prosecuted Galileo for heresy and sentenced him to life imprisonment. It forced him to recant too.
He was under house arrest until his death in 1643. In the history of science, Galileo was a perfect embodiment of the conflict between science and religious doctrines.
In the final stage of his life, he became blind, perhaps a consequence of constantly staring at the Sun through his telescope while studying sunspots.