Last month I attended a celebration of the 450th anniversary of the birth of Galileo, co-hosted by the Italian Embassy in Washington. The keynote speaker was Nobel laureate Carlo Rubbia, the former Director General of CERN, who was recently appointed senatore a vita by the President of Italy.
Hearing one giant of physics describe the achievements of an even bigger giant got me thinking about Galileo’s legacy to modern physics. Galileo understood that mathematics, theories, experiments and experimental tools are all part of the same package. Rather than argue Aristotelian philosophy for another millennium, Galileo knew that systematic observations of the phases of Venus could conclusively rule out the Ptolemaic system, with no ifs, ands or buts. This test required a high-tech experimental tool — the telescope — known to Galileo only by second-hand rumors. So he painstakingly built and refined his own telescopes, about a hundred in all, several of which I have seen in the Museo Galileo in Florence. With the right tool in hand, he turned it to the sky to see what he could see. The rest, as they say, is history.
Another Italian physicist, Enrico Fermi, carried the Galilean style of physics into the modern era. A brilliant theorist, Fermi wrote a paper in 1933 that explained the phenomenon of nuclear beta decay in terms of a new weak interaction involving an as yet unseen particle that he called a neutrino. He submitted his revolutionary paper to the prestigious journal Nature, where it was promptly rejected for containing “speculations too remote from reality.” Undeterred, Fermi began to broaden his horizons to include experiment. By 1938 he had a Nobel in his pocket for experiments with slow neutrons, inducing what we now know to be nuclear fission. By 1942, Fermi was in Chicago, designing and overseeing construction of the first nuclear reactor.
Fittingly enough, Fermilab has a long and proud history of contributions from Italian physicists. Giorgio Bellettini brought Italian groups into the CDF collaboration in 1980, stayed on to lead one of the top quark discovery analyses and still organizes the successful summer program that brings Italian students to Fermilab. Recently Ornella Palamara and Flavio Cavanna arrived here to lead parts of our liquid-argon neutrino program, and Professor Rubbia himself is preparing to bring the ICARUS detector to Fermilab after a major revamping at CERN. Viva Italia!