





What is it?

Light Speed! is an OpenGL-based program developed to illustrate the effects of special relativity on the appearance of moving objects. When an object accelerates to more than a few million meters per second, it begins to appear warped and discolored in strange and unusual ways, and as it approaches the speed of light (299,792,458 m/s) the effects become more and more bizarre. In addition, the manner in which the object is distorted varies drastically with the viewpoint from which it is observed.

These effects which come into play at relativistic velocities are:

The Lorentz contraction - causes the object to appear shorter The Doppler red/blue shift - alters the hues of color observed The headlight effect - brightens or darkens the object Optical aberration - deforms the object in unusual ways

They are described in greater depth in the About page. Highlights of the simulator's capabilities are listed on the Features page.

See Light Speed! in action

(The screen shots are here!) (The screen shots are here!)

To run Light Speed!, you will need:

A Unix/Linux workstation running the X Window System

A fast CPU (then again, what today doesn't require one? :-)

OpenGL or Mesa3D libraries

Light Speed! also requires the GTK+ toolkit library. (Binaries with this library compiled in statically will be made available in the future)

Antony Searle, of the Australian National University, is author of the BACKLIGHT raytracer, another excellent program for illustrating relativistic phenomena. It uses a four-dimensional raytracing engine (loosely based on POV-RAY) to produce its images, and is a better tool to use if greater accuracy and/or more rendering flexibility is needed. There are various sample images and movies online, which are certainly worth a look.

David Porterhouse maintains a Relativistic Flight Simulation page, with links to various other programs and movies illustrative of relativistic effects. Some of these center on general relativity (which considers gravitational forces), with heavy emphasis on black holes and the like. Fascinating material.

I would like to thank the following people for their assistance:

Professor Alan Guth , of the MIT Physics Department, for fielding some tricky questions (tricky for me anyway)

, of the MIT Physics Department, for fielding some tricky questions (tricky for me anyway) Antony Searle , for letting me use the Doppler-shift code from BACKLIGHT, and providing valuable insight into the physics of it all

, for letting me use the Doppler-shift code from BACKLIGHT, and providing valuable insight into the physics of it all Justin (you know who you are) for pointing out to me one really small but really stubborn bug. You saved my sanity. (Oh, and using that Octane to debug wasn't half bad either }:-)

(you know who you are) for pointing out to me one really small but stubborn bug. You saved my sanity. (Oh, and using that Octane to debug wasn't half bad either }:-) The brave souls of the SIPB

Everyone who has written in with their comments and suggestions!

This project is generously hosted by

Light Speed! was written by Daniel Richard G., a former student of Computer Science at the Massachusetts Institute of Technology.