The following equation has been derived to try to determine the minimum mass for a stable black hole.

g = c^2/[2r

_{s}+L/2

]

However some caution is necessary. The kinematic equation for distance traveled due to free fall is:

d = v

_{i}t + (1/2)at^2

v

_{i} is the initial velocity, t is elapsed time, a is acceleration and d is the displacement. Any object having an initial velocity when far from a black hole may ultimately acquire superluminal velocity before reached the event horizon due to its initial velocity. If instead of the Chandrasekhar limit we use a value of 3 solar masses we find that the acceleration falls below c. In order for this to be the minimum black hole mass it needs a proof of non-superluminal speed before the event horizon. Otherwise physics breaks down exactly where it shouldn't.