Galileo Galilei was one the greatest astronomers in the world. He changed the way we look at the universe. Galileo was the first person to use a telescope. Galileo studied the sun, the planets, and the moon.
Galileo Galilei was the eldest of 7 children, he was born in Pisa on February 15th 1564. He was born in the same year as Shakespeare and also the year Michelangelo died. When he was born, there was no Italy as we know it today. It was made up of independent states, the states were in regions. Pisa belonged to the Tuscany region, controlled by the Medici family.
Galileo’s father was Vincenzio, and his mother, was called Giulia. His father was a gifted musician and mathematician, he was also a cloth merchant to earn extra money. Galileo’s father educated him until he was 10. The next year his family moved to Florence. A year later, Galileo attended the Benedictine Monastery of Santa Maria di Vallombrosa. There, he studied Latin, Greek, music, logic and religion.
Before Galileo Galilei, all humans believed that the earth was the centre of the universe, and the sun revolved around the earth. This theory is called the Ptolemaic theory, named after a roman astronomer Ptolemy. The roman Catholic church also believed this theory. Then, in 1543, Nicolaus Copernicus published a theory that the earth revolves the sun, this was called the Copernican theory. His theory was thought a solemn challenge to the Ptolemaic theory. Unfortunately Copernicus died before he could prove this theory.
Galileo studied this theory, he wanted to finish Copernicus’ work by proving it, or disproving it. The way he made this possible was by inventing the telescope, in 1609. In December 1609, Galileo looked at the moon through his telescope and discovered numerous things. He exposed the fact that the moon doesn’t create light, but reflects it. And that the moon is not flat as Aristotle had believed, but in fact it has mountains, valleys and craters on it, just like the earth. In 1610, he made an important discovery about Jupiter, this changed the way we now think, this was that there appeared to be 4 stars orbiting Jupiter. Later he realized that in fact, these stars were moons. Therefore proving Copernicus’ theory. It proved that the moon can orbit around the earth while the earth orbit’s the sun. Galileo discovered 4 moons on Jupiter, but now we know there are at least 60 moons of Jupiter. The 4 moons discovered by Galileo are the 4 biggest known so far. These moons are called; Io, Europa, Ganymede and Callisto. In 1637, Galileo uncovered that the moon has a regular libration (Rocking movement).
Galileo made other observations using the telescope. He discovered that the milky way is made up of billions of individual stars. The planet Venus has phases similar to the moons, Saturn has rings, Sunspots move across the sun’s surface. All of these observations not only made Galileo even more famous than he already was, but it also led to the development of astronomy to become a major branch of science.
Galileo is known as the Father of modern science as not only did he do all of the above, but he was one of the first people ever to use scientific ways to carry out experiments. He used new scientific inventions to prove or disprove the beliefs of the ancient Greek philosophers, e.g. Aristotle.
Galileo started experimenting with pendulums after he saw a light swing in the Pisa Cathedral. He realized each swing of the light took the same amount of time, even though it was a shorter swing than the previous one. This led to Galileo’s discovery of the Law of the Pendulum. In his experiments, he included experiments with falling objects as Aristotle believed that heavier objects fall to the ground quicker than lighter objects. Legend has it that Galileo dropped two different objects of the same size at the same time from the top of the tower of Pisa to prove or disprove Aristotle’s theory. Both objects fell to the ground at the same time. This disproved Aristotle and led Galileo to discover the Law of Falling Bodies.
Unfortunately Galileo died on January 8th 1642, in Arcertri near to Florence. He lived for 77 years. He was buried in Santa Croce cemetery in Florence. Galileo’s experiments and findings of the planet Jupiter are extremely important, to honour Galileo’s contributions the four moons which he discovered are called the Galilean moons. There is also a spacecraft named after him, that was launched on 18th October 1989. It was sent to orbit Jupiter it finally reached and started orbiting in 1995. Galileo proved that the Earth is not in the middle of the solar system and it revolved on its axis around the sun.
Galileo was an amazing astronomer and scientist, his many discoveries have changed the modern world.
By Alex Grady