In 1609 Galileo revolutionized the world with his new invention, a telescope capable of reaching the moon and discovering the satellites orbiting around Jupiter, something unthinkable in the midst of the Holy Inquisition, contrary to scientific advances and progress. We are in the midst of the Scientific Revolution, the 17th century.

Galileo Galilei was born in Pisa (Tuscany) on February 15, 1564 into a wealthy family and the lower Pisan nobility. His father was a well-known mathematician and musician who wanted his son Galileo, the eldest of his offspring, to study medicine, and so it was, Galileo studied medicine, mathematics and philosophy.

When he discovered his invention in 1609, a telescope made by himself by hand with 20x magnification and that could see the stars of the Via Lactia, the sky, the moon and its craters or Saturn, it was a revolution and above all it had with the opposition of the Church. Galilei thought that the conception that the Polish astronomer Copernicus had about the universe was the most appropriate. He himself was a faithful follower of Copernicus’ heliocentrism theory for fifteen years.

This one, Galileo’s, was the first recorded telescope, even surpassing the one already built by a Dutchman a short time before.

Photo: Galileo’s original telescope.- Museum of the History of Science in Florence.

Heliocentrism: Thesis that was born in classical times in Greece by Aristarchus of Samos that in a certain way contradicted the geocentric theory of the famous philosopher, Ptolemy. For his part, Copernicus (1473-1543) studied and improved the thesis of heliocentrism, demonstrating that the apparent movements of the sun and the stars could be explained thanks to the double rotation of the Earth, a daily rotation on its axis and its annual translation. around the Sun. In other words, the Earth is the one that rotates around its axis and not the sun. In classical Greece, man was the center of the universe, but heliocentrism considered it wrong to think of that, since it was the earth that rotated and the sun was the center of the planetary system, closest to the earth. The three movements of the earth were already then, daily axial rotation, annual orbital movement and conical-annual movement on its axis.

Galileo was able to determine the value of gravitational acceleration, which regulated the movement of bodies falling towards the center of the earth, by studying the fall of the furthest spheres along inclined planes, the acceleration of gravity and the the conservation of energy. From the motion of the spheres, some simple measurements were exposed for the different angles to obtain a value, a little lower than the current one, known as 9.80665 m/s2, which due to systematic errors due to attrition, cannot be completely removed.

For this reason, the theory of heliocentrism meant questioning the biblical texts; the consequences were not only theological, but also metaphysical and ontological consequences, which produced various scientific reactions.

Galileo clarifies that the mountains of the Moon are similar to those of the Earth and that the spots on the solar surface contradicted the theory of perfection of the stars above the Moon.

Jupiter is surrounded by four satellites that revolve around it in a similar way to what happens to the Moon. To go further, the planet of Venus already declared that it had phases, the ones we know today.

Before building his telescope, Galileo begins to prove his ideas about the center of gravity. In 1586 he reconstructs an Archimedean hydrostatic balance. His projects and ideas about the studies on the oscillations of the heavy pendulum come to light as his new invention, the heart rate monitor, which allows to measure the pulse and on a time scale allows to know its value. He becomes interested in falling bodies and starts working in a studio.

As a university professor at the University of Padua, he continues to show his admiration for Copernicus and passes on his teachings; they grant him the title of professor of Duke Cosme II de Médicis. In 1592 he was appointed professor of mathematics at the University of Padua and built his first gas thermometer.

Thanks to the offer of the University of Florence, Galileo is invited to observe the Tower of Pisa, since it was leaning more and more. His studies on the Tower lead him to clarify these following points:

a) From the top floor of the Tower of Pisa, every object dropped to the ground, from that height, took the same time (in time) as in proportion (weight) to reach the bottom.

b) That its trajectory was always constant, the same, vertical. This contradicted what Aristotle defended many centuries ago. = Theory of Gravity.

Because of these conclusions, Galileo was removed from the university and even sued by some student at the time.

In 1606 he builds his first thermostat, the first of his kind in the history of science. He wants to know and objectively compare the levels of heat and cold. He will begin to study the power and structure of magnets.

Three years later, and after learning that a Dutchman had created a telescope, he set about creating his own. The crystals he uses magnify the Dutch six times and give him another perspective that helps discover more of the Milky Way.

Shortly after the first telescope, Galileo decides to create another one, even better, and increases it with objectives that reach 8 or 9 times more than the first; he will present it to the Senate of Venice.

In 1610 he already had more than 30 telescopes, but none of them satisfied him completely. He also creates the first microscope. In 1611 he enters the Academia dei Lincei, the first scientific society of the time.

In 1615 he is denounced by the Inquisition. He had to appear before the Court on more than one occasion to defend his opinions and studies and on occasion he retracted it.

In 1638 he became blind, but he will continue working, at that time he decides to move to live in his house near the sea of ​​San Giorgio and his disciples accompany him.

He died at his house in San Giorgio (Arcetri-Tuscany) on January 8, 1642; his body was buried in the church of Santa Croce. His tomb was created to house his remains, almost a hundred years later, as it dates from the date of March 13, 1736.