Can we define an event without reference to space and time? And why would this be useful? Laura Mersini-Houghton explains.
At the heart of modern physics lurks a terrible puzzle: the two main theories that describe the world we live in just won't fit together.
The holy grail for 21st century physics is to produce a unified theory of everything that can describe the world at every level, from the tiniest particles to the largest galaxies. Currently the strongest contender for such a theory is something called M-theory. So what is this supposed mother of all theories all about?