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Welcome to the Space-Time Lab

This Java applet demonstrates some physical effects of Einstein's Special Relativity. On the left is a graph of "space", in each experiment you will see objects moving through space here. On the right is a space-time diagram of all the objects and the observer. In general,

BLUE = ObjectRED = Observer

To begin an experiment:

  • Choose an experiment using the pull-down menu.
  • Choose a speed you would like the main object in the experiment to move at.
  • Choose the frame you would like to see using the frame toggle button Switch Frames.
  • Press START to begin experimenting!
  • Press RESET to be able to restart a new experiment at a different speed.
  • Press Java TA to run through the lesson for this applet.

The buttons functions are:

STARTPress the start button to put the system in motion.
STEPPress the step button to increment time manually
RESETPress the reset button to reset all variables and enable the velocity scrollbar.
Click for Java TAWant to really know what makes Special Relativity tick? Press the Java TA button to start up the Java teaching assistant. The button will disappear and the teaching assistant will load.
For an HTML version of the Java TA click here.
Press this to switch which rest frames the graphs are made from. The Object in the Observer's rest frame moves with velocity v, but in the Object's rest frame it has velocity zero (while the Observer with respect to the Object has velocity -v). The orthogonal axes in the Space-Time diagram are those of the rest frame's.
Use the scrollbar to adjust the velocity v.

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