Time stops for no one. It continues to move forward. We are so used to hearing that, we never pause to think about the alternative. Physicists, however, do think like that and they have been trying to understand the phenomenon for decades. They have just uncovered conditions that makes time run in reverse.
They didn’t build a time machine yet so keep your plans to visit the dinosaurs on hold for now. The research tells us why time only moves forward. Before we get into the depth of the experiment, we need to know about how time works. The principal feature we use to define time is the movement of energy.
Its explanation lies in the thermodynamic principle of entropy, which means disorder. As our universe is cut off from gaining energy, things tend to go from ordered to disordered. To put it simply, if you place a hot object in a cold room, you can’t expect the object to get hotter and the room to get colder. Hot things tend to cool down.
Many experiments have shown that even on a microscopic level, particles behave as dictated by the initial conditions. In short, they are moving forward. but scientists have finally found an exception to this generalization and discovered conditions to make time run in reverse.
The team looked at chloroform, a molecule made up of a carbon atom connected to one hydrogen and three chlorine atoms. A strong magnetic field was used to line up the nuclei of carbon and hydrogen atoms when the molecules were suspended in acetone. Then, they manipulated a property of the particles called spin.
Now what should happen is that as one nucleus warms up, it should transfer the random movements to colder particles till the time they are both at the same temperature. This is what happened under normal conditions, but there was an exception to this when the particles were correlated.
The particle correlation made a significant difference to how energy was shared between the bodies. The heated hydrogen particles got even hotter, while their colder entangled carbon partner got colder. In other words, the study revealed the thermodynamic equivalent of reversing time in a very tiny pocket of the Universe.
“We observe a spontaneous heat flow from the cold to the hot system,” the team writes in the study. Even though the study is on a very small scale, it shows us that time isn’t absolute. This has also opened new doors to the field where quantum mechanics and thermodynamics overlap and scientists are still researching it.
Further investigations and experiments to make time run in reverse will reveal if it can be converted to a macroscopic level and if these experiments are a success, they could open doors to a number of technical applications.