★Contingency is an indispensable element of disorder in the development of science.
★A dialogue between an astrophysicist and a historian, two friends engaging in a semi-serious exchange, casually yet rigorously delves into a variety of scientific discoveries, from radio astronomy to the discovery of the Americas continent, from the gamma-ray bursts to the steam engine, guiding us through an understanding of the evolution of science and the advancement of knowledge.

Discoveries are the salt of scientific research, the pivotal moment in scientific progress. But how do they happen and how do we get there?

In an unconventional format of a semi-serious dialogue between two friends, we will explore various scientific discoveries in a relaxed yet rigorous manner, thereby progressing along the many paths of scientific development. Discoveries can be the beginning of the path, its end, the result of dedicated research, or entirely unexpected events. Some discoveries turn out to be mistakes, while others are even proven to be hoaxes. In some cases, their significance is immediately apparent, whereas in other instances, it takes prolonged contemplation to fully comprehend their implications. Then there are the purely accidental discoveries, and we can count many such discoveries that span a wide range of disciplines.

From radio astronomy to the discovery of the Americas continent, from the mysterious gamma-ray bursts kept secret by the U.S. military for years to the late inventions of the steam engine and the bicycle, the two protagonists, through sudden topic changes, jokes, curiosities, explanations, and detailed yet always accessible, descriptions, accompany us on an adventure that explores the many ways in which knowledge progresses and the crucial role of serendipity in man's scientific and technological advancement.

Tommaso Maccacaro (Pavia, 1951), astrophysicist, has worked in Italy, England and the United States. He has held numerous positions in research management and organization. He was chairman of committees of ESO and ESA, director of the Brera Astronomical Observatory and finally president of the National Institute of Astrophysics. He has combined his research activities with a strong commitment to science popularization. He edited the essay La ricerca tradita (Garzanti 2007) and helped found the online journal «Scienzainrete.» With Tartari he published Storia del dove. Alla ricerca dei confini del mondo (Bollati Boringhieri, 2017).

Claudio Maria Tartari (Milan, 1951), an elementary school teacher from 19 to 39 years old - mainly devoted to the logicalmathematical area - graduated in History with a medieval focus and specialized in paleography. He then directed a conservation library with a historical-legal focus in Milan for as many years. He has published some 30 works, the majority focusing on the history of the Milanese territory. He has been a lecturer for decades.