Back To Michael's Page
The Doppler Demonstration

by Michael Loyd - michael@loydnet.com

This is a java program that demonstrates the Doppler effect due to an object's speed relative to the speed of light (about 300,000 km/s).

This applet can be ran as both an applet (click button at bottom of page) and a program. You might find it useful to download the Doppler.jar file to run the program offline. To run it as a program see the first bullet in "Some Issues" further down on this page. The idea for the program was spawned by the Physics department at Davidson College. But the program here was written by myself. The entire program was written by hand (none of those fancy editors!). Here's my documentation.

Terms
c - speed of light (almost 300,000 km/s)

Applet Properties
The applet demonstrates a couple of properties by running on 2 separate threads.
  1. Relative Speed Of Galaxy
    One thread is the rate at which an object is receding from the earth. In this thread, a numerical value is multiplied by c to give a value relative to c. Currently the program initializes at 50% and increments or decrements by 50% upon clicking the buttons at the top of the window.

  2. Speed Of Light
    Another thread utilized is a constant thread which reflects c. This remains a constant simply because c itself is constant. If a blackbody object is at rest it will emit light radiation at almost 300,000 km/s. If it is moving at any percentage of 300,000 km/s, it will still emit radiation at almost 300,000 km/s in any direction. In other words, if you are going the speed of light (which is not possible, but for argument's sake so you can) and turn on your headlights you won't see anything! Note to people self conscious of their weight: As you approach the speed of light, your mass approaches infinity.... The c thread is the Doppler.class itself. The Doppler thread increments each active RadiationWave object every 30 milliseconds. c in this example was arbitrarily set to 4. So c is equal to 4 pixels/30 milliseconds or 133.3 pixels/s. The Radiator.class, which operates under its own thread, constructs a new RadiationWave every 300 milliseconds at the galaxy location and expands at the rate of c.

Things To Notice
Observe the wavelengths at the left and right of the galaxy. When the galaxy speed is stationary, you will see equal radiation frequecies at either side. When traveling at 50% of c you will see the radiation start to "squash" together on the side of the galaxy vector. And as you hit c the waves are stacked on top of each other.

If you had an anti-matter warp cores you would notice that you could travel at "warp" speed - speeds faster than light. This doesn't say that your direct speed would be faster than light but your speed relative to an object not in "warp" would appear faster than light. Imagine walking down the sidewalk in a straight line towards a tree. Then all of a sudden the side walk between you and the tree was squashed together effectively bring the tree closer. The distance you traverse in one step, which previously was about ~3 feet, is now ~15 feet. You aren't taking bigger steps now compared to before the warp began so relatively speaking you aren't traveling any faster than you were before. But you will certainly get to that tree alot faster. Speed above c is noted as warp - <c/c> (ie. Warp 1.5 which indicates 150% light speed). How fast can you go?

So without further ado, click the button to start.



Some Issues
Last Modified 05/04/99 16:46:56
Back To Michael's Page