Comparisons

The following animation compares the different visual relativistic effects as speed increases. The circles show these effects at different angles around the eye. From left: angular compression, doppler shifting, and the headlight effect.

Angular compression (left): At rest the arrows indicate light coming in from all directions. As the observer accelerates the arrows move to show the direction the light appears to be coming from due to aberration. Light concentrates in the direction of motion as speed increases.

Doppler shift (centre): At rest the green circle represents green light coming from all directions. As the speed increases the colour at each angle shows the colour that this has been doppler shifted to. At low speed the rear is red (red shift) and the front blue (blue shift). At higher speeds a colored band is surrounded by black to the front and rear. To the front the black represents ultra-violet, and to the rear infra-red. The middle of the coloured band is green and shows the direction in which there is no doppler shift. Because of angular contraction this is not at an angle of 90 degrees.

The headlight effect (right): At rest the grey circle represents light of uniform brightness coming from all directions. As the speed increases the intensity at each angle shows the headlight effect: the rear is darkened and the front brightened. The separation between the light and dark sections shows the direction in which there is no change in brightness. Again, this does not occur at an angle of 90 degrees.