Are extra dimensions visible near the event horizon: Black holes coupled to scalar fields

In terms of the Kaluza-Klein theory the authors study some properties of the spherically symmetric gravitational field coupled to a massless scalar field and discuss the final state of the gravitational collapse. The static field with a naked singularity is unstable and generates a large disturbance of the scalar waves. Even if an event horizon forms, the scalar disturbance continues to develop. This suggests that the extra space can enlarge with the lapse of time to a visible size near the disturbed black hole