Recent content by ebm_teacher

In the Wikipedia entry on mass-energy equivalence*, there is a reference to an elementary derivation of mass-energy equivalence in an article by Rohrlich (AJP 1990), which apparently expands on the original thought experiment by Einstein (ie observer in middle of moving train, light pulses...

In Sean Carroll's "From Eternity to Here", pages 69-70, the author says that people in a sealed spaceship out in space can tell when they accelerate (they are pushed "down" to the floor say by a rocket firing at the rear of the craft), or when they rotate (an object perfectly positioned at the...