The paradox does not arise in the Big Bang or its successful Lambda-CDM refinement, which posit that the universe began roughly 13.8 billion years ago, not long enough ago for the universe to have approached thermodynamic equilibrium. Some proposed further refinements, termed eternal inflation, restore Kelvin's idea of unending time in the more complicated form of an eternal, exponentially-expanding multiverse in which mutually-inaccessible baby universes, some of which resemble the universe we inhabit, are continually being born.