Bubble of nothing

In theoretical physics, a bubble of nothing is a physical instability that is found in higher-dimensional spacetime models. It was first described by Edward Witten in 1982, as a consequence of the positive energy theorem. It represents a non-perturbative decay channel of Kaluza–Klein theory, in which spacetime can spontaneously collapse through the nucleation of a gravitational instanton. This bubble of nothing has no interior, not even spacetime.
Bubbles of nothing are forbidden in models that include supersymmetry.
It has been considered as an hypothetical end of the universe mechanism. As bubbles of nothing have not been observed, their absence can be used to put constraints on other theories.