### lightspeed-1.2 README file

    ==== Light Speed! ====

    DESCRIPTION

         This is a simulator designed to illustrate relativistic effects on
    the appearance of objects moving at ultra-high velocities.

         It simulates a geometrical lattice object traveling at a given speed
    in a straight line through space. Specifically, the object moves along the
    x-axis of this space, in the positive-x direction; at time t=0, the object
    is precisely centered on the origin.

         The simulator displays, in essence, a still image of the vicinity of
    the origin snapped at the exact moment that the object is *seen* to be at
    the origin; i.e. the moment that light reflected off the object, when the
    object was exactly at the origin (at t=0), eventually reaches the camera.
    This moment will usually be a few billionths of a second after t=0,
    accounting for the time needed for the light to traverse this distance.
    (The camera's info display will explicitly indicate the time of the
    snapshot, to 0.001 microsecond accuracy).

         Light Speed! will allow you to move around and see interactively how
    the object appears to change with observer position. At low velocities,
    this isn't much the case, but up in the several-million-meters-per-second
    range, the object as viewed from one angle to another can vary
    significantly.

         To get started, drag the slider at the right of the window upward.
    Relativistic effects will immediately become noticeable. Click and drag
    in the graphics window to move around. Have fun!

    THEORY

    Light Speed! takes into account the following consequences of special
    relativity:

      1. Lorentz contraction     (fast objects appear shorter)
      2. Doppler red/blue shift  (the Doppler effect on light/color)
      3. Headlight effect        (redistribution of reflected light)
      4. Optical aberration      (warping due to the finite speed of light)

    A lengthier treatment of the above phenomena, complete with the formulae
    used (really, they're not that bad!) may be found in the file MATH.

    LIMITATIONS

    The only major weakness of this simulator is color. The Doppler shifts
    produced are only approximations, and in certain cases may be wildly
    inaccurate. If color fidelity is a must, Antony Searle's BACKLIGHT
    raytracer program may be a better choice. (See the Acknowledgements
    section below for details).

    REQUIREMENTS

    Light Speed! requires the X Window System with OpenGL or Mesa3D support,
    as well as the GTK+ libraries to function. Compilation will additionally
    need Janne Lof's GtkGLArea widget. See the file INSTALL for more.

    ACKNOWLEDGEMENTS

    I would like to thank Antony Searle, of the Australian National
    University, for allowing me to make use of the Doppler-shift code from his
    well-received relativistic raytracer, BACKLIGHT. This program illustrates
    relativistic effects via a four-dimensional raytracing engine, and I
    highly recommend it in case greater scientific rigor or creative
    flexibility is desired. You may find it at:
    http://www.anu.edu.au/Physics/Searle/

    ====================================
    Daniel Richard G. // <skunk@mit.edu>