This application should run on computers that use the Microsoft Windows or Linux operating systems. Unfortunately it does not run on the Mac OS. To run this application you must have the Java Runtime Environment (JRE) version 7 or later installed on your computer, a web browser that will run the Java Plugin and you must be connected to the Internet. As of this writing, the latest Java version is 1.7.0_21 (often referred to as just version 7).
If you don’t have the Java Runtime Environment (JRE) version 7 or later:
If you don’t have at least Java Runtime Environment 7, or just want to play it safe, you may download the latest update free from Oracle Corporation at,
Note: Java SE stands for Java Standard Edition. JRE stands for Java Runtime Environment. JDK stands for Java Development Kit. You do not need JDK. Click the button “Download JRE” and follow the instructions for your computer platform.
If you do have the Java Runtime Environment (JRE):
If Java is installed you should have access to the Java Control Panel. On Microsoft Windows, it is accessible from the Windows Control Panel.
Windows Start -> Control Panel -> Control Panel Home -> Programs -> Java
The Java Control Panel is a small application that manages the options for Java.
This application will run with the defaults assigned when you install Java, but to be safe, do the following;
Make sure Java Cache is enabled
Java Control Panel > in the section “Temporary Internet Files” > Settings (button) > check “Keep Temporary Files on my computer”
Clear the Java Cache to get a clean start
Java Control Panel > in the section “Temporary Internet Files” > Settings (button) > Delete Files (button) > OK (button)
3. Make sure your security settings match the picture below.
Java Control Panel > Security
Running Java Applications:
Most browsers no longer run Java automatically. You must load and enable a Java Plugin.
For Firefox version 20, select Tools -> Add-ons -> Plugins to view the plugins that you have. If you do not see an item called something like “Java TM platform SE 7” you cannot run java applications from your browser. Select the “get Add-ons” link and follow the instructions to load the Java plugin. (You only need the SE. You do not need the JDK)
For Internet Explorer version 9, select Tools -> Manage Add-ons -> Toolbars and Extensions. If you do not see at least one “Java (TM) Plugin SSV Helper” item select the “find more toolbars and extensions” link and follow the instructions to download the Java plugins.
Other browsers should have similar options.
Click on the URL below. Alternatively you may paste or type the URL in the address bar of your web browser,
This application is an evolving product. So you may see a simple redirect link for you to click like the one pictured below.
Click the “Here” link and you will get the Main Page of the web site. It should look something like the picture below. If you are reading this Requirements Document, you probably got it from this web page.
In the section labeled “Simulation Program:” click the button that says “Launch”. You will be prompted to open the Java Web Start Launcher. That’s java’s name for a program that downloads a java application from the web. You may save the program if you want to run it later, but for now leave the option at “Open” and click OK. Open means Run in this situation.
It may take a minute or two to fully load. After that most of the files will remain in your Java Cache which you can clear anytime you want. If you can’t get the application to load, you can still read the tutorials. There are lots of pictures from the application. Toward the end of the load you may get a security warning that looks like this.
This means the application’s digital signature is not registered. I am in the process of registering. Please trust me. Check the accept box and click Run. When the application finishes loading, your web browser should will open a separate window for the application and you will see a blank simulation scene as pictured below. You may now close your web browser at any time without affecting this application.
Above the scene, you will notice tabs. The simulation scene is the first tab. Below the scene, at the bottom of the page, you will see various buttons and controls. If you cannot see the full application window, it may be because your monitor is not set to a good resolution. The application is best run when your monitor is set to a 1280 by 960 pixel screen area. From the above window you can load predefined examples or individual objects to create your own examples. If this is your first time using the application, it is recommended that you follow one of the tutorials listed in the main web page at
Good luck and have fun learning Special Relativity!