For over a century, physics has treated time as a silent background — a dimension in which events unfold, much like frames on a film reel. But what if the reel isn’t already complete? What if “time” itself only begins when the universe makes an irreversible change? In our latest work, we show that the flow of time can emerge from one simple but profound process: the creation of new, committed information. Before this threshold, the universe is in what we call the pre-temporal regime — a state where changes can still occur, but they must be perfectly reversible, leaving no permanent trace. Cross that threshold, and the “arrow of time” appears, forged by records that cannot be erased.
This information-driven view of time isn’t just philosophical musing. It comes with hard mathematics, testable predictions, and experiments we could perform with today’s quantum technology. From laboratory ion traps to the first moments of the cosmos, the same rule applies: no irreversible information, no operational time. The implications are profound — not only does this mean that time is a local, physical property that can vary from place to place, it also shows that existence itself is possible outside of time. In the pre-temporal world, reality unfolds without any operational “before” or “after,” its changes forever poised to be undone. In short, the clock we live by may be one the universe writes for itself — and sometimes chooses not to write at all.from place to place, and perhaps even switch on and off.