Galileo by his telescope transformed Astrology into Astronomy in the modern sense and started the physical understanding of heavenly bodies. However, telescopes based on Geometrical Optics do not allow to see much at stellar distances. Further progress in the theory of light and its properties was needed for the study of stellar sizes, shapes and details such as star spots. This story is an elementary account of the physical principles that made such measurements possible and of some of the main results. …

Michele Cini

Retired Full Professor, Tor Vergata University. Quantum Theory of Transport, Pumping, Magnetism, Superconductivity, Non linear Optics, Electron Spectroscopy,..