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Apparent Velocity
Shows how the apparent velocity b depends on β and angle θ.
Here:
- radial speed is the speed along the line of sight between the object and the detector; positive for approaching, negative for receding.
- transverse speed is the speed at 90° (perpendicular) to the line of sight.
Interesting to note:
- green curve: an approaching object's apparent radial speed has no upper limit
- green curve: a receding object's apparent radial speed is never less than -0.5c
- white curve: at 90°, the apparent transverse speed is simply the value of β
- white curve: an approaching object has a maximum apparent transverse speed, as shown by the peak of the white curve.
Curiously, for very high speeds, the value of θ for which the maximum transvere motion occurs is not that large.
That is, the maximum transverse motion occurs when the direction of motion is not far from being
directly toward the detector.