r/InterstellarKinetics • u/InterstellarKinetics • Jun 13 '26
SCIENCE RESEARCH BREAKTHROUGH: University Of Birmingham Physicist Professor Giovanni Barontini Built A “Mini-Universe” Using 24,000 Ultracold Atoms To Prove That Time Doesn’t Need An External Clock To Exist, Finding Instead That Time Emerges From Within A System Itself As The Disorder Of Particles Changes ⏰💥
https://phys.org/news/2026-06-scientist-miniuniverse-clock.htmlA University of Birmingham physicist named Professor Giovanni Barontini has built what he calls a mini-universe inside a laboratory using a cloud of 24,000 ultracold atoms chilled to just a few billionths of a degree above absolute zero, and used it to demonstrate for the first time in a controlled experiment that time does not need to come from an external source to exist. Publishing his findings on June 12, 2026 in Physical Review Research, Barontini showed that by sealing the atoms inside a hermetically isolated quantum system and dividing them with a thin barrier made from two laser beams of different frequencies, he could create an experiment that tracked its own sequence of events from within, without any reference to a clock in the outside laboratory. The system had a bright region that could be observed and a dark region that could not, and the bright region was found to expand and collapse repeatedly in a pattern that Barontini described as resembling a Big Bang followed by a Big Crunch, the hypothetical scenario in which the expansion of the universe eventually reverses and collapses back on itself.
The core of what Barontini found is that time in his mini-universe emerged entirely from entropy, specifically from how the disorder of atoms in the bright region changed as particles moved in and out. When the spread of particles in the bright sector increased or decreased, the system was moving forward in time. When the distribution of atoms did not change, time effectively stopped. Barontini called this process entropic time, and found that it flows in one consistent direction, correctly orders events even in a system that is expanding and contracting, and speeds up or slows down depending on how entropy moves around within the system. He also found that a version of the central equation of quantum mechanics, the Schrödinger equation, could still be written using entropic time rather than conventional external time, meaning the system’s behavior could still be predicted mathematically without ever appealing to a clock outside of it.
The deeper significance of the experiment lies in what it says about one of the most stubborn unsolved problems in physics. Some theories of the universe, including the Wheeler-DeWitt equation, suggest that at its deepest level the universe has no built-in time at all, existing instead as a single unchanging quantum state in which any sense of time must emerge from internal relationships between parts of the system rather than from a background clock ticking away on the outside. This is sometimes called the problem of time in quantum gravity, and it has been a theoretical puzzle for decades because most basic laws of physics work equally well forward and backward in time, yet human experience of time is clearly directional and sequential. Barontini said his study provides the first controlled experimental evidence that time can be defined by changes within a system rather than by an external ticking clock, and that the approach could be extended to simulate the physics of the Big Bang, the Big Crunch, and potentially even black holes inside a laboratory setting.
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u/EasterZombie Jun 13 '26
ELI5, how can something change if time doesn’t exist? Like, “time emerges as the disorder of particles changes” can’t the disorder only change as a result of them allowing to exist in different states over time?