Black holes generally are defined as stellar objects which do not release any light. The Schwarzschild radius, derived from GRT, defines the;horizon radius for non-rotating black holes. The Kerr metric is supposed to define the ‘event horizon’ of rotating black holes, and this metric is derived from generally ‘acceptable’ principles. The limit for the Kerr metric’s horizon for non-rotating black holes is the Schwarzschild radius.;By analyzing the horizon outcome for rotating and non-rotating black holes, using the Maxwell Analogy for Gravitation (or historically more correctly: the Heaviside Analogy for Gravitation, often called gravitomagnetism), I find that the Kerr metric must be incomplete in relation to the definition of ‘event horizons’ of rotating black holes. If the Maxwell Analogy for Gravitation (gravitomagnetism) is supposed to be ‘a good approach’ of GRT, we may assume that it is a valid analysis tool for the star horizon metrics.;The Kerr metric only defines the horizons for light, but not the ‘mass-horizons’. I find both the ‘light-horizons’ and the the ‘mass-horizons’ based on MAG. Moreover, I deduct the equatorial radii of rotating black holes. The probable origin of the minutes-lasting gamma bursts near black holes;is unveiled as well. Finally, I deduct the spin velocity of black holes with a ‘Critical Compression Radius’.;The deductions are based on the findings of my papers ‘Did Einstein Cheat?’, ‘On the Geometry of Rotary Stars and Black Holes’, and ‘On the Orbital Velocities Nearby Rotary Stars and Black Holes.

Keywords: Maxwell Analogy, gravitation, gravitomagnetism, rotary star, black hole, Kerr Metric, torus, gyrotation, light horizon, mass horizon, angular momentum