In his discussion of accelerated motion on page 60 of "The Meaning of Relativity," Albert Einstein made an approximation that allowed him to develop the theory of relativity further. Einstein ...

In a new Physical Review Letters study, researchers propose an experimental approach that could finally determine whether gravity is fundamentally classical or quantum in nature. The nature of gravity ...

During its teenage and young adult years—what is now referred to as its “classical” period—physics made a lot of mistakes. In the old physics, mass and energy were separately conserved; particles’ ...

The theory of special relativity is rife with counterintuitive and surprising effects, the most famous of which are length contraction and time dilation. If an object travels at a relative speed, ...

Since 2007, physicist Leonard Susskind has regularly delivered a lecture series called the Theoretical Minimum, on the foundations needed to study different areas of ...