Aspetti moderni della Fisica Greca

The translations into modern languages of the books and papers by ancient scientists (let us confine ourselves, here, to physicists) have been the praiseworthy work of scholars whose fields of competence, however, were too often in humanities, rather than in science. Such translations, therefore, miss points important for modern physics, since for a good translation it is of course necessary a good understanding of the topic. [Even in the case of a rather recent author like Leonardo da Vinci, whose language was not that different from modern Italian, many translations into current languages are misleading]. In our opinion, scientists with a deep knowledge in physics, and a rare interest in its history, have to revise all the enourmous body of the ancient physicists’ writings. To give an idea of the terrible effort that should be undertaken in this respect by physicists, we call attention in this brief article to some extremely “modern” results, frequently overlooked, got by ancient Greek physics. Since the present e-print is in Italian, let us translate here, into English, at least two remarkable claims: (i) Posidonius (circa135-51 BC) wrote: «Matter is endowed with a cohesion that keeps it together and against which the surrounding vacuum has no power. Indeed, the material world is supported by an immense force, and alternately contracts and expands in the vacuum following its own physical processes, now consumed by fire, now, instead, giving rise to a new creation of the cosmos»; (ii) Plutarchus, circa 100 AD, in his early book on “astrophysics” --in which he exposed, in a sense, a general theory of gravitation-- wrote the noticeable passage: «The Moon gets the guarantee of not falling down just from its motion and from the dash associated with its revolution, exactly as stones in slings cannot fall due to their circular whirling motion; in fact, each thing is dragged by its mere natural motion only if it isn’t deviated by something else. The Moon, therefore, is not dragged down by its weight, because its natural tendency is frustrated by its revolution. And, on the contrary, it would be really amazing if it remained at rest always at the same place, like the Earth».