Although the development of the germ theory of disease in the latter half of the nineteenth century marks a major revolution in medical science, comparable to the discoveries of Galileo in astronomy or Darwin in biology, it cannot be reduced to the heroic efforts of a single researcher or group of researchers. Rather, a number of conceptual, technological and institutional preconditions made the germ theory possible. Among these, contagion...more
Professor Bailyn introduces the course and discusses the course material and requirements. The three major topics that the course will cover are (1) exoplanets--planets around stars other than the Sun, (2) black holes--stars whose gravitational pull is so strong that even their own light rays cannot escape, and (3) cosmology--the study of the Universe as a whole. Class proper begins with a discussion on planetary orbits. A brief history of...more
The Voyager spacecraft that toured through the giant planets of the Solar System, Jupiter's Galileo orbiter and the Cassini-Huygens mission to Saturn and Titan have given us wonderful views of these most beautiful planets and shown us, in Titan, a world that is surprisingly like our Earth - but at - 180° Celcius!
In this introductory lecture, Professor Lewin discuses basic units, dimensions, measurements and associated uncertainties, dimensional analysis, and scaling arguments. Further, he explains why a measurement is meaningless without knowledge of its uncertainty, using data collected by Galileo Galilei as an example. He begins to dive into dimensional analysis, reasoning that the time from an object to fall from a certain height is independen...more