In this paper, we study blow ups of solutions to the second sound equation ∂t2u=u∂x(u∂xu), which is more natural than the second sound equation in Landau-Lifshitz's text in large time. We assume that the initial data satisfies u(0,x)≥ δ>0 for some δ. We give sufficient conditions that two types of blow up occur: one of the two types is that L∞-norm of ∂tu or ∂xu goes up to the infinity; the other type is that u vanishes, that is, the equation degenerates.
