Seminars

3pm Thursday 24 September 2009, S2 Lecture Theatre, Building 25
School of Mathematical Sciences Colloquium
Is all motion relative?
Donald Lynden-Bell (IoA, Cambridge)

Newton's invention of Absolute Space was essential for the development of Dynamics but Leibniz and later Mach rejected it. Einstein showed it was not absolute but did not remove the influence of space on mechanics completely. We first give a truly relative classical mechanics which is in exact agreement with Newton's in our non-rotating universe. We then demonstate that General Relativity gives all the main Machian effects and conclude that only spaces closed by the mass of the energy they contain obey Mach's precepts. Other solutions of Einstein's equations do not obey his boundary conditions and may be considered unphysical.