In black holes this force is so strong that not even light can escape
... black 
holes throw out jets of high speed particles at almost the speed of light ... a black 
hole has so strong a gravitational field inside the Schwartzschild radius that 
nothing (not even photons) can escape, how come these material particles 
escape... [DOC] [TLE] Stephen Hawking explains how to (sort-of) escape a black hole ... [PAR] Aug 25, 2015 ... ... is so strong that absolutely nothingnot even lightcan escape once inside.