You Could Fall Through the Earth in 38 Minutes 🌍

Dig a tunnel from the North Pole to the South Pole and jump in. You'd pop out the other side in about 38 minutes, hitting 35,000 km/h (22,000 mph) at the center. And on the way down, gravity does something most people get exactly backwards. 0:00 Falling through the Earth 0:29 An old idea 1:09 What's down there 2:07 How deep we've actually dug 2:51 The rules 3:40 The jump 4:05 Gravity gets stronger 4:41 The center 5:10 The other side 5:31 What if there's air? 6:08 The gravity train 6:58 Could we build it? THE NUMBERS 38 minutes pole to pole · 35,000 km/h (22,000 mph) at the center Gravity peaks ~9% stronger at the top of the core, ~2,900 km (1,800 mi) down Kola Superdeep Borehole: 12,262 m (40,230 ft), deeper than the deepest ocean SOURCES Klotz, "The Gravity Tunnel in a Non-Uniform Earth", American Journal of Physics (2015): arxiv.org/abs/1308.1342 Inge Lehmann, "P′" (1936): discovery of the inner core Gravity train: Hooke to Newton (1679), Lewis Carroll (1893), Paul Cooper, Am. J. Phys. (1966) IMAGE CREDITS (Wikimedia Commons) Galileo by Justus Sustermans, 1636 (public domain) · Dialogo frontispiece by Stefano della Bella (CC0, The Met) · Robert Hooke reconstruction by Rita Greer, 2004 (Free Art License; no authentic portrait survives) · Isaac Newton by Godfrey Kneller, 1689 (public domain) · Principia title page, 1687 (public domain) · Lewis Carroll by Oscar Rejlander, 1863 (public domain) · Inge Lehmann by Even Neuhaus, 1932 (public domain) · Earth from Apollo 17, NASA (public domain) · Kola borehole site by Andre Belozeroff (CC BY-SA 3.0) · Mponeng gold mine by JMK (CC BY-SA 4.0) Animation, music and sound by Tiny Probe. Narration is AI-generated. Big universe. Small probe. Real physics. Subscribe for a new explainer every week. #science #physics #space