Letters; June 2009; Scientific American Magazine; by Staff Editor; 2 Page(s)

End without Horizons? In Naked Singularities, Pankaj S. Joshi argues that models for stellar collapse can produce naked singularities, or singularities without the event horizon that surrounds a black hole. According to quantum theory, black holes emit thermal radiation and evaporate because of the separation of particle-antiparticle pairs near their event horizon. Will a naked singularity ever disappear? Daniel Chamudot Riverdale, N.Y.

If an event horizon has an extreme but finite spacetime curvature and gravity, and in a singularity these are infinite, how can there be any path between a low-gravity and curvature region and a singularity without passing through a horizon? Lloyd Anderson Villa Park, Ill.