The physics of nothing:

The physicist Edward Witten first discovered the “bubble of nothing” in 1982. While studying a vacuum with one extra dimension curled up into a tiny circle at each point, he found that quantum jitters inevitably jiggled the extra dimension, sometimes shrinking the circle to a point. As the dimension vanished into nothingness, Witten found, it took everything else with it. The instability would spawn a rapidly expanding bubble with no interior, its mirrorlike surface marking the end of space-time itself.