Electrical Network Frequency analysis, ENF analysis, matches background hum against power grid logs. I talked to one of the researchers who works on it, and also set them a challenge. Thanks to @answerinprogress, @hannahwitton and @SteveMould! 🟥 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