Uploaded October 2016 | Updated September 2026, 2 weeks ago

---

Produced on site at New Scientist Live 2016! This was a question from the #MendeleyWall, a giant wall in the Mendeley booth where people wrote down the questions they had for science.

Illustrated by Claudia Stocker (vividbiology.com), narrated by Lisa Dennison (sciencesketches.org).