Most people agree that, outside of science fiction movies, time constantly moves forward. As such, determining how much time has passed since a given event is usually as simple as checking a clock. But what if watches had never been invented? Would it still be possible to find out when (and in what order) different things happened? According to Giovanni Barontini, a scientist at the University of Birmingham, this is not only possible, it is the reality in which we live. To test the hypothesis, Barontini created a “miniature universe” composed of approximately 24,000 rubidium atoms, cooled almost to absolute zero so that they acted more like a collective cloud than individual particles. These were locked in an inescapable trap, which was split in half by a specially configured laser. One side (the “bright” side) was observed while the other (the “dark” side) was not. In this experiment, the changing entropy of the bright side was used to track time, meaning that the internal stopwatch only advanced when the atoms crossed the laser barrier. By measuring the way the cloud expanded and contracted, as well as the exchange of atoms, it was possible to reveal the order in which events happened. However, because it is possible for time to effectively stop (when there is no atomic exchange between the sides), the recorded internal clock did not agree with the external clock as to when exactly the events occurred. Read more: 5 states with the most wind turbines (and how much energy they produce) What does this mean for our understanding of time? Brianajackson/Getty Images Basically, this experiment shows that in a controlled environment, it is possible to measure the flow of time simply by measuring entropy changes in an atomic system. This is enormously important because the two models that underpin our current understanding of physics, Einstein’s theory of general relativity and quantum mechanics, do not always agree on what time is or how it works. For example, in certain situations, it is possible to reverse time in specific quantum systems. Therefore, this experiment is a step towards unifying these two theories and learning why events that occur on a planetary scale do not always happen the same way in quantum environments. It is important to recognize that this is only the starting point for future experimentation. After all, it does not simulate several factors that could affect the flow of atoms, such as black holes, and there are many other variables that could be changed, including the shape of the trap, the atomic density, and the height of the laser barrier. The cloud’s repeated oscillation between the dark and bright sides could also help scientists simulate conditions immediately after the Big Bang, and potentially even the period leading up to the Big Crunch, when the universe theoretically collapses in on itself. The true impact of this experiment on physics probably won’t be evident for a while, but at least there are now several ways to track exactly how long it takes. Did you enjoy this article? Subscribe to BGR’s free newsletter and add us as a preferred search source or follow us on Google for the latest in tech and entertainment, plus tips and advice you’ll actually use. Read the original article on BGR.
