[watsisname]

Here's an application you may find interesting; modelling the orbits of particles close to a black hole, using general relativity.  To quote the site,

In Newtonian gravitation, an orbit is always an ellipse. As the gravitating body becomes more massive and the test particle orbits it more closely, the speed of the particle in its orbit increases without bound, always balancing the gravitational force. For a black hole, Newton's theory predicts orbital velocities greater than the speed of light, but according to Einstein's Special Theory of Relativity, no material object can achieve or exceed the speed of light. In strong gravitational fields, General Relativity predicts orbits drastically different from the ellipses of Kepler's laws. This page allows you to explore them.

http://www.fourmilab.ch/gravitation/orbits/

[Colonol Dekker]

Well that killed my phone.

[Colonol Dekker]

Well that killed my phone.

[Mongoose]

DOUBLE KILL!