Why Time Speeds Up as You Age

It lays out two rival explanations for why your years pick up speed, side by side. This lesson works out which one the evidence backs, and takes apart a number you’ve probably heard repeated as a fact.

Before you start. You need nothing more than your own memory of a childhood summer that felt endless, and a recent year that felt like it vanished in a few weeks. Everything in the story half is arithmetic you could do with a calculator, and it never goes further than multiplying and comparing.