The second law of thermodynamics delineates an asymmetry in how physical systems evolve over time, known as the arrow of time. In macroscopic systems, this asymmetry has a clear direction (e.g., one can easily notice if a video showing a system’s evolution over time is being played normally or backward).
Click here for original story, A machine-learning algorithm that can infer the direction of the thermodynamic arrow of time
Source: Phys.org