Physicists have built a miniature universe in the laboratory and observed time emerging from changes within it, without any external clock to measure it. The experiment, led by a University of Birmingham researcher, could help address one of the most persistent questions in physics: what time is, and where it comes from.
The system uses 24,000 ultracold atoms arranged as an isolated quantum system. The researchers caused it to repeatedly expand and contract, a process that mimics the Big Bang and a possible Big Crunch. Remarkably, the experiment showed that a sense of time could arise from the changes taking place inside the system itself, rather than relying on an outside reference to keep track of it.
The findings speak to a long-standing puzzle. In most physics experiments, time is treated as a fixed background against which events unfold, measured by a clock that sits outside the system being studied. The new work suggests that, at least in this controlled setting, time can be understood as something that emerges from the evolution of the system's own parts. That idea matters because the origin of time remains open in both quantum theory and cosmology, where the laws governing the universe have not yet been fully reconciled.
Because the miniature universe is built in a laboratory, researchers can adjust its conditions and observe how its behavior changes, something that is impossible with the real cosmos. That makes it a testing ground for theoretical ideas about the early universe and the nature of time. The experiment does not itself establish how time works in the universe at large, but it offers a way to check whether competing models make predictions that match what happens in an isolated system.
The work sits within a broader effort by physicists to use controlled quantum systems to probe questions usually confined to theory. Such experiments can produce measurable data on phenomena that cannot be observed directly, giving researchers concrete results to compare against theoretical expectations.
The source material available for this report is limited to the summary of the Birmingham experiment. A separate article about the Deep Underground Neutrino Experiment in South Dakota's former Homestake mine was included in the research package, but it describes a different project and contains no verified details about the miniature universe, so it has not been used for facts in this story.
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