  In a static gravitational field an intersection of a worldline by a global
hypersurface of simultaneity t=const gives an invariant constraint relating the
proper time of this event by t. Since at any finite t the such constrained
proper time intervals are less than reqiured for crossing a horizon, general
relativity predicts the gravitational freezing of proper times in stars with
time-like or null geodesics everywhere. The time dilation stabilizes
contracting massive stars by freezing, which is maximal but finite at the
centre, and the surface is frozen near the gravitational radius. The frozen
stars (frozars) slowly defrost due to emissions and external interactions, the
internal phase transitions can initiate refreezing with bursts and explosions.
