Outline of the Physics

Abstract

4Physics and Culture indelibly linked to Albert Einstein (1879Einstein ( -1955, and quantum mechanics on the incredibly small scale. In the late twentieth century, physics has seen the development of string theory whose foundation is not experimental and has similar characteristics to postmodernism in the arts. 7 The fundamental particles in string theory, which are point particles in quantum theory, have extension albeit extremely small. Gabriele Veneziano is considered to have written the first paper on string theory in 1968 but its origins, in the concept that some at least of the fundamental particles had extension, go back to 1943 and the S-matrix of quantum physicist Werner Heisenberg (1901Heisenberg ( -1976. 8 The postmodernism of string theory, which has not become fully accepted, has not yet caused a revolution in physics. Newtonian PhysicsNewtonian physics was the culmination of the first scientific revolution but it did not start from a vacuum. As Newton recognized himself in a letter to Robert Hooke (1635-1703) written in 1676: 9 'If I have seen further it is by standing on the shoulders of Giants.' Newton's Giants extended back to the Ancient Greeks and even earlier. Nicolaus Copernicus (1473-1543), Johannes Kepler (1571-1630), and Galileo Galilei (1564-1642) led the revolution in science that enabled Newton to synthesize terrestrial and celestial mechanics. The Principia consists of three books, the first deals with forces and motion in free space, the second expands the treatment of motion to resisting media and the third book applies the first two books to the System of the World. At first Newton tells in the introduction to Book 3 he had originally intended to present this last book in a popular style but decided later that it would lack clarity and lead to misunderstanding and so wrote it in the same mathematical style as the first two books. However he told William Durham (1657-1735), a natural philosopher and rector at Upminister, that he made it difficult 'to avoid being baited by little Smatterers in Mathematicks'. In the beginning of the sixteenth century the cosmology was that of Claudius Ptolemaeus (ca. 90-168), known in English as Ptolemy, who lived in Egypt, which was then part of the Roman Empire, and died in Alexandria. The Earth was at the centre of the universe in Ptolemy's astronomy. The fixed stars revolved around the Earth on perfect circular orbits, but the Sun and the planets moved relative to the fixed stars and could not follow exact circular orbits. In Outline of the Physics 5 particular the superior planets like Jupiter or Saturn, which are further from the Sun than Earth, seem at times to have retrograde motion and at some periods of the year appear to move westwards relative to the stars instead of in the usual easterly direction. To account for this apparent motion, Ptolemy had the planets and the Sun follow epicyclic paths (a curve traced by a point on a circle which rolls around another circle). Even then the centre of the main circle had to be displaced from the cent...