The theory of general relativity provides us with excellent tools to study and predict the dynamics of objects in the vicinity of gravitating bodies, as long as the latter are considered to be ...

The state of a physical system has no absolute meaning, but is only defined relative to the observer’s reference frame in the laboratory. The same system may be associated to different states in ...

The reference frames from which observers view quantum events can themselves have multiple possible locations at once — an insight with potentially major ramifications. Imagine standing on a railway ...