The end-Cretaceous mass extinction was a cataclysmic asteroid impact that ushered in the end of the non-avian dinosaurs and forever changed the course of evolution on Earth. But what can we say about the timing of the event, other than it happened 66 million years ago?

Well, it turns out that Tanis, a relatively-recently discovered fossil site in North Dakota, is full of lines of evidence that are allowing earth scientists to piece together when the impact occurred.

In this episode, we’re joined by Melanie During, Uppsala University, who has been examining the details of the bones of fish to say more about the world either side of the event.