Grey? Blue? Purple? It can look different, depending on the context. Let's talk about color perception, color temperature, and the history of laundry. Atmospheric opacity image from ESA/Hubble (F. Granato): https://www.eso.org/public/images/atm_opacity/ - image licensed under CC by 4.0 - https://creativecommons.org/licenses/by/4.0/ The optical illusion is original, but based on the work of David Novick: https://twitter.com/novickprof/status/1139342022551191553 More on Illuminant D65: https://en.wikipedia.org/wiki/Illuminant_D65 - the references in this article go into the full technical detail 🟥 MORE FROM TOM: https://www.tomscott.com/ (you can find contact details and social links there too) 📰 WEEKLY NEWSLETTER with good stuff from the rest of the internet: https://www.tomscott.com/newsletter/ ❓ LATERAL, free weekly podcast: https://lateralcast.com/ null ➕ TOM SCOTT PLUS: null 👥 THE TECHNICAL DIFFICULTIES: null