How one theory ties together everything we know about the universe

The following is an extract from our Lost in Space-Time newsletter. Each month, we hand over the keyboard to a physicist or mathematician to tell you about fascinating ideas from their corner of the universe. You can sign up for Lost in Space-Time for free here.

Though our world is bewildering in its diversity, all known natural phenomena can be classified into just a few categories. Four of these – gravitational, electromagnetic, strong nuclear and weak nuclear – are…