Real Time Relativity [RTR], developed by Craig Savage and his team at the Australian National University, allows you to “fly through” a virtual world at relativistic speeds.
RTR+EM is a modified version of RTR, incorporating relativistic electromagnetism. RTR flies through a static “world” which contains electric charges – Lorentz transformations modify the electric field relative to that seen by a static observer, as well as generating a magnetic field. Electric and magnetic field vectors can be displayed individually, or simultaneously. RTR scenarios are specified via XML files – these can be edited, so charge configurations can be modified by the user without recompiling the code.
RTR+EM does not support accelerated charges, and thus does not model radiation. However, it demonstrates relativistic transformations of the electric field and the relativistic origin of the Biot-Savart law, where the magnetic field of a constant current is the consequence of viewing electric charges in a boosted frame.
RTR+EM is “forked” from version 1.60 of RTR, and released under the GNU Public License. Installers for Mac and Windows executables as well as the source code can be found below. The source code includes a number of graphics elements and ancillary libraries needed to compile the code, and is approximately 200MB (compressed).
RTR scenarios are specified via XML files – these can be edited, so charge configurations can be modified without recompiling the code.
KNOWN ISSUES: This software is released on an “as-is” basis, and remains a work in progress. It worked on MacOS 10.5 through 10.6.4 and recent versions of Windows. However, we make no promises that it will continue to work, although the executable runs on MacOS 10.11. The “game” is played with the keyboard (or mouse), and needs a bit of practice before you can easily manoeuvre through space.
RTR+EM does not support accelerated charges, so does not model electromagnetic radiation. However, it demonstrates relativistic transformations of the electric field and the relativistic origin of the Biot-Savart law.
BASIC COMMANDS: Hit “Escape” to get the main menu, and to set the keys (or mouse) used for steering. Hitting the “E” key will toggle the display of the E field, the B field, E and B together, and no electromagnetic fields. The “M” key turns other relativistic distortions off and on. When these are on, the layout of the charges is changed by the standard relativistic effects which RTR was designed to display. The 8 and 9 keys move the plane in which the field values are displayed backward and forward, in a line between the “observer” and the center of the RTR co-ordinate system.
FEEDBACK: This project is not currently being updated, but any comments would still be welcome!
USES AND APPLICATIONS: If you use RTR+EM in your teaching, or just find it informative, please let us know!
ACKNOWLEDGMENT: This work was supported by the National Science Foundation (CAREER-PHY-0747868), and the Paul Moore fund of Yale College. We are very grateful to Craig Savage and his collaborators for generously placing RTR under an open source license, and thus making RTR+EM possible. We also thank Michael Williamson for technical advice on the initial implementation of the electric and magnetic field vectors inside RTR.
AUTHORS: Richard Easther and Katherine Rosenfeld