THE engineer has no difficulty in understanding entropy. The boilerman says : “I give you steam with so much heat energy and entropy, and you want to know how much work your engine will get out ...

According to Sean Carroll, the most mysterious thing about time is its direction. This mystery arises from the fact that the known fundamental laws of physics are time-symmetric: by themselves ...

Ludwig Boltzmann, a 19th-century physicist, proposed that the arrow of time arises from the statistical behavior of particles ...