This directory contains documents and interactive resources which explore aspects of both Newton's theory of universal gravitation and Einstein's general relativity.
The first two installments in the series are now available.
We live our entire lives within the Earth's gravitational field, yet
rarely if ever do we experience the universality of
gravitation: that every object in the universe attracts and is
attracted by every other. This page presents a “basement
science” experiment which reveals the gravitational attraction
between objects less than a kilogram in mass. Knowledge in antiquity
suggesting gravitation was universal is discussed, and the feasibility
of an experimental test using only materials and techniques of the era
is explored.
Close-in orbits around compact massive objects such as neutron stars
and black holes trace out paths drastically different from the
ellipses of Kepler's Laws. Since the velocity of an orbiting object
cannot attain or exceed the speed of light, Einstein's general
relativity predicts a different energy curve, resulting in precession
absent in Newton's theory. This page includes an interactive
animation that lets you explore such orbits and explains the theory
behind them.