3.1 The Internal Geometry Shift (IGS)

3.1.3 Visualizing the IGS transformation

As previously described, an observer's perception of a straight line is tilted backward when the observer is speeding up and looking sideways. Objects appear to be farther away when the observer is looking forward and closer when he or she is looking backward. The optical effect of this geometrical transformation can be equated to changing the focal length of a camera lens. This effect is very similar to the optical appearance effect that manifests when the observer is changing velocity. The primary difference is that the optical appearance effect is not simply a visual effect; it is an effect on the actual geometry to which one has adapted oneself when one changes velocity.