"General Relativity for Undergraduates: The Jungle and the Explorers."
Professor Edwin Taylor
General relativity underlies our contemporary understanding of the big bang, black holes, pulsars, quasars, x-ray sources, gravitational waves, gravitational focusing of light, and the evolution of the Universe. Undergraduates specializing in physics naturally want to know more (to paraphrase James Hartle). Undergraduates start with the metric, the solution of Einstein's field equations. A metric describes spacetime around a black hole using the language of differentials that can be manipulated with single-variable calculus. How does a stone move through this spacetime? A hint from the twin "paradox" tells us that the stone moves so as to maximize the time on its wristwatch; the stone obeys the Principle of Maximal Aging. With the metric on one hip and the Principle of Maximal Aging on the other, the undergraduate explorer plunges deep into the jungle of general relativity. No one who knows a subject should be allowed to write a textbook without advice from students, because professionals no longer share student difficulties. How can students help authors to explain their subject to the students' satisfaction? Ask members of William Ingham's class Physics 297: Special Topics -- Relativity