Galileo Galilei (1564-1642) was an Italian scientist of the 16th century, closely linked to the Scientific Revolution experienced by the West during that century, due to his contributions in the fields of physics, astronomy, engineering and mathematics. For instance: perfect the telescope, discover the satellites of Jupiter, study sunspots. He also showed an interest in the arts (music, painting, literature) and is considered in many ways the father of modern science.
The son of a family belonging to the lower nobility, he studied at the University of Pisa, Italy, where he studied medicine, but especially mathematics and physics, becoming a follower of Euclid, Pythagoras, Plato and Archimedes, thus moving away from the prevailing Aristotelian positions. Later he would act as a university professor in both Pisa and Padua, in the latter much more freely, since he belonged to the Republic of Venice where the Inquisition was not so powerful.
its scientific career it was brilliant and lavish in discoveries, as well as in theoretical confirmations that debunked much of what was held to be true about the world at the time. This motivated the Holy Inquisition of the Catholic Church to pay attention to its treatises and publications, condemning the Copernican theory (heliocentric, opposed to geocentrism) that Galilei would both defend as “nonsense, an absurdity in philosophy and formally heretical”.
Forced to present the results of his experiments as hypotheses and show no evidence in their favor, he was censored in 1616 and formally convicted in 1633 on charges of heresy. During the process, they force him to confess his crimes under threat of torture and to publicly retract his ideas, which he does so that his sentence to life imprisonment is commuted to home incarceration.
According to tradition, when forced to admit in public that the earth does not move (since it was the center of the universe according to Aristotelian theories), Galileo added the refrain “Eppur si muove”(However, it moves) as an ultimate way of sustaining his scientific ideas in the face of ecclesiastical censorship.
He will finally die in Arcetri at the age of 77, surrounded by his disciples and completely blind.
Examples of contributions by Galileo Galilei
- Perfect the telescope. Despite not having invented it properly, since in 1609 Galileo himself received the news of the appearance of an artifact that allowed us to see objects at enormous distances, it is fair to say that Galileo contributed decisively to the manufacture of telescopes as we know them . By 1610 the scientist himself acknowledged having built more than 60 versions of it, of which not all worked properly and that, on some occasion, exposed him to embarrassment in front of the authorities. However, theirs were the first to obtain a straight image of what was observed, thanks to the use of divergent lenses in the eyepiece.
- Discover the law of isochrony of pendulums. The guiding principle of pendulum dynamics is so called, so it is fair to say that Galileo discovered them as we understand them today. He formulated a principle that states that the oscillation of a pendulum of a given length is independent of the maximum distance it moves away from the equilibrium point. This principle is that of isochronism, and he tried to apply it for the first time in the mechanisms of clocks.
- Build the first thermoscope in history. Devised in 1592 by Galileo, this type of imprecise thermometer made it possible to distinguish the rises and falls in temperature, although it did not allow to measure them or propose any type of point scale. Still, it was a huge advance for the time, and the basis for any temperature measurement technology. Today they are preserved, but as decorative objects.
- Postulate the law of uniformly accelerated motion. It is still known today by this name to a type of movement that a body experiences, the speed of which increases over time at regular intervals and in regular amounts. Galileo arrived at this discovery through a series of mathematical theorems and hypotheses and, it is said, the observation of a falling stone, whose speed increases regularly in time.
- He defended and proved the Copernican theories over the Aristotelian ones. This refers specifically to the geocentric vision proposed by Aristotle three hundred years before Christ, and which was formally accepted by the Catholic Church, as it was in harmony with its creationist precepts. Galileo instead defended the thesis of Nicolás Copernicus, for whom the center of the universe could not be the earth, around which the stars rotate, but the sun: the heliocentric thesis. This defense through various tests such as the observation of the moon, the tides, other phenomena of the cosmos and the birth of new stars (nova), would earn Galileo persecution by the forces of the Church and his many rivals scientists.
- Prove the existence of mountains on the moon. This verification, as well as the others that show his interest in astronomy, are, of course, after the making of the telescope, a device that revolutionized the life of the Italian. The observation of the mountains of the moon contradicted the Aristotelian precepts of the perfection of the sky, according to which the moon was smooth and immutable. This despite the fact that it was unable to correctly calculate its dimensions, given the impossibility of knowing the distance between the earth and the moon at that time.
- Discover the satellites of Jupiter. Perhaps Galileo’s most famous find, so much so that the moons of Jupiter are known today as the “Galilean satellites”: Io, Europa, Callisto, Ganymede. This observation was revolutionary, since verifying that these four moons orbited around another planet showed that not all celestial stars revolved around planet Earth, and this evidenced the falseness of the geocentric model fought by Galileo.
- Study sun spots. This discovery also allowed to refute the supposed perfection of the heavens, despite the fact that scientists of the time attributed them to the shadow of certain planetoids between the sun and the earth. The demonstration of these spots allowed us to suppose the rotation of the Sun, and therefore also that of the Earth. Checking the Earth’s rotation was to undermine the idea that the Sun was moving around it.
- Investigate the nature of the Milky Way. Galileo makes many other observations of the stars in our galaxy, within the range of his modest telescope. Observe novae (new stars), prove that many visible stars in the sky are indeed clusters of them, or get a glimpse of the rings of Saturn for the first time.
- Discover the phases of Venus. This other finding, in 1610, reinforced Galileo’s faith in the Copernican system, since the apparent size of Venus could be measured and explained according to its passage around the sun, which did not make sense according to the Ptolemaic system defended by the Jesuits. , in which all the stars revolved around the Earth. Faced with these irrefutable proofs, many of his rivals took refuge in the theories of Tycho Brahe, in which the Sun and the Moon revolved around the Earth and the rest of the planets around the Sun.