In the cooling Universe after the Big Bang, a field (quantum field), like an invisible web, froze into partitions between regions with different vacuum properties. These walls, a thousand times thinner than an atom, should have, by calculations, acquired monstrous mass and distorted the cosmic microwave background and the expansion of the Universe. But observations of redshift from distant supernovae show the opposite: the walls are gone.

The solution was found in numerical simulations. If the masses of field excitations on opposite sides of the wall differ, it becomes a rocket: energy rushes toward the lighter vacuum, and the wall itself gets a push in the opposite direction. The network of walls starts moving, colliding, and collapsing; calculations that even include curved spacetime confirm a rapid decay.

This mechanism requires no new particles and naturally explains the absence of walls today. Their collisions generate gravitational waves — ripples in spacetime that future observatories might detect.