Born in Pavia in 1501 and died in Rome in 1576, a very long life for that time, especially if we think that his mother while she was pregnant did everything to procure an abortion and that he was practically stillborn, miraculously brought back to life by the midwife thanks to a bath with vigorous frictions in wine (sic!).
In his youth he studied law and medicine at the University of Pavia and accompanied his father, a lawyer on his visits, meeting people of immense value, such as Leonardo da Vinci.
Cardano is an astrologer, doctor, mathematician, engineer, gambler, philosopher, magician, inventor.
Versatility is quite common for the times, but Cardano, unlike other equally versatile contemporaries, bequeathed us inventions and discoveries that are still fully in use today, and scientific insights that amaze with their futuristic reach.
Cardano experienced moments of fame and wealth in his life, mainly linked to his medical skills and as an astrologer and soothsayer - gifts that led him around Europe to treat bishops and nobles, perhaps even the king of England, of whom certainly fill in the horoscope. But he also experiences moments of despair and poverty due to his family events, his bad character and his behavior that is not always ethically correct, which will put him in conflict with his colleagues and finally also with the inquisition, who will not forgive him, among other things, of having written a horoscope of Jesus.
Cardano is probably the most brilliant scoundrel of all time, in his mind, rationality and magic, mathematical precision and astrology coexist. But do you really believe in magic and astrology? Probably very little, but he understood that, given that most of his contemporaries believe in it, one can get by, and even quite well.
Cardano invents (or rediscovers) the joint that bears his name, which transforms the plane of motion from vertical to horizontal or vice versa. The cardan joint still moves our cars today, in addition to mills, wind turbines and many other things.
To Cardano we also owe the cardanic suspension, which is also used in nautical compasses, keeping them still in case the boat sways. This mechanism is also still in use today.
But the best of itself Cardano undoubtedly gives it in mathematics: contributes to the formula for solving cubic and quartic equations ed is the recognized precursor of probability theory (which will later be developed by Pascal and Fermat), which Gerolamo twenty-year-old thinks of as he wanders from one tavern to another in Pavia, the city where he studies medicine.
Winning at the game is the only way he has to make ends meet and probabilistic calculus helps him.
A few years later he discovers (or invents) the imaginary and complex numbers that are at the basis of the mathematics of quantum physics (appear in the Shroedinger equation, which describes the evolution of a quantum system) and many electronic technologies.
An imaginary number i has the form x = √-1 or x₂ = -1, and is called i. The imaginary unity i, which is not a real number, has the property of being equal to the square root of -1. From the union of i with real numbers complex numbers are generated. It is thanks to the complex numbers that Gerolamo develops the solution of the equations of the third and fourth degree.
In reality, part of the solution is communicated to Cardano by Nicolò Tartaglia (another rather picturesque character) with the promise not to divulge it. Gerolamo instead develops the formula of the solution in full and publishes it in his work ars magna. The result is a stormy controversy which will have as its epilogue the arrest of Cardano by the Inquisition, of which Tartaglia is a good friend and confidant.
Cardano is also a forerunner of Braille writing as he is among the first to think about a tactile reading system and how to make it, even if his approach is still analog.
Moreover, his contributions to the cryptography.
Thanks for the contribution Paolo Riccardo Felicioli