In ordinary discourse, an event is a happening lasting some duration during which some object changes its properties. Physicists use the term ‘event’ this way, but they also speak of events composed of point-events in which no value is intended for any physical variable, and this is another meaning of the word 'event'. The latter type of event is simply a point location in space and time, with no requirement that anything happens there then. Usually only the context suggests what is intended.
The point-event is fundamental in science in the sense that any object is just a series of its point-events and the values of their properties. Point events are simply locations in spacetime with zero duration.
Strictly speaking, this notion of an event is an idealization. It specifies a definite time and place, whereas any actual event is bound to have a finite extent, both in time and in space. All fundamental laws of physics are written in terms of point-events. For example, the process of a ball’s falling down is a continuous, infinite series of point-events along the path in spacetime of the ball.
- In relativity, an event is the instantaneous physical situation or occurrence associated with a point in spacetime (that is, a specific place and time).
- Hermann Minkowski (1864-1909) had in mind that the world of events forms a four-dimensional continuum.