The first law of thermodynamics states the principle of energy conservation for systems in which heat and work interactions can take place and the internal energy of the system can change. Using unit ...

The famous second law of thermodynamics says that the world gets more and more disordered when random chance is at play. Or, ...

The grandfather paradox is just one of the thorny logical problems that arise with the concept of time travel. But one physicist says he has resolved them.