Apparent superluminal motion of a revolving subluminal body

Abstract

This paper aims to determine the conditions for apparent superluminality for a revolving subluminal body. Using signal-delay transformations, we showed that a revolving subluminal body may be perceived by an observer as apparently superluminal. For an object to become apparently superluminal, its orbital speed must exceed a distance-dependent threshold value. In astronomically relevant contexts, this threshold is approximately 0.707 times the speed of light.