We all know what we mean when we say that something has happened — well, all except for theoretical physicists. That's because the notion of a "happening" becomes very fuzzy when you go right down to the foundations of the science, where not even time and space are clearly defined. From Newton's classical physics to Einstein's general relativity and the weird theory of quantum mechanics, these articles and videos explore the notion of events in physics — or lack of it.
What's happening? — Time and space form the stage on which events unfold. But what if the stage itself becomes part of the action? We take a brief tour through the history of space and time and see how ideas have changed since the time of Isaac Newton.
Is it happening? — The strange theory of quantum mechanics has turned our conception of reality on its head. This article explores how things become fuzzy in the microscopic world and what this means for our understanding of events.
It's happened! — With all the trouble caused by quantum mechanics and people's attempt to construct a theory of everything, we might be better off defining an event without reference to time and space. It's easier than you might think!
Anthony Aguirre on the trouble with events and observers.
Sean Carroll explains why it's hard to define events and what to do about it.