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For decades, scientific models of our universe have included the possibility that it exists as a long-lived, but not completely stable, sector of space, which could potentially at some time be destroyed upon 'toppling' into a more stable vacuum state. The Standard Model of particle physics opens the possibility of calculating whether the universe's present state is likely to be stable or merely long-lived. A catastrophic bubble of "true vacuum" could theoretically occur at any time or place in the universe, which means (because the bubble of "true vacuum" will expand at the speed of light) the end of our false vacuum could occur at any time.

If the Standard Model is correct, the particles and forces we observe in our universe exist as they do because of underlying quantum fields. Quantum fields can have states of differing stability, including 'stable', 'unstable', or 'metastable' (meaning, long-lived but capable of being "toppled" in the right circumstances). If a more stable vacuum state were able to arise, then existing particles and forces would no longer arise as they presently do. Different particles or forces would arise from (and be shaped by) whatever new quantum states arose. The world we know depends upon these particles and forces, so if this happened, everything around us, from subatomic particles to galaxies, and all fundamental forces, would be reconstituted into new fundamental particles and forces and structures.

A hypothetical 'vacuum metastability' event would be theoretically possible if our universe was in fact part of a metastable (false) vacuum in the first place. A false vacuum is one that appears stable, and is stable within certain limits and conditions, but is capable of being disrupted and entering a different state which is more stable. If this were the case, a bubble of lower-energy vacuum could come to exist by chance or otherwise in our universe, and catalyze the conversion of our universe to a lower energy state in a volume expanding at nearly the speed of light, destroying all that we know without forewarning.