Why is it Hot Underground?

Subscribe to MinuteEarth! - http://www.youtube.com/user/minuteearth?sub_confirmation=1 And support us on Patreon: https://goo.gl/ZVgLQZ ________________________ Created by Henry Reich Production and Writing Team: Alex Reich, Peter Reich, Emily Elert, Ever Salazar, Kate Yoshida, and Henry Reich Narrated by Emily Elert Illustrated by Omkar Bhagat - https://www.youtube.com/user/c0defap Music by Nathaniel Schroeder - http://www.soundcloud.com/drschroeder ________________________ Free iTunes podcasts of MinuteEarth! - https://goo.gl/sfwS6n Facebook - http://facebook.com/minuteearth Twitter - http://twitter.com/MinuteEarth MinuteEarth provides an energetic and entertaining view of trends in earth s environment -- in just a few minutes! ________________________ References England, P. C., Molnar, P., & Richter, F. M. (2007). Kelvin, Perry and the Age of the Earth. American scientist, 95(4), 342-349. https://www.americanscientist.org/my_amsci/getFile.aspx?id=14035015574935 Perry, J. (1895). On the age of the earth. Nature, 51, 341-342. Thomson, W. (1862). XV.—On the Secular Cooling of the Earth. Transactions of the Royal Society of Edinburgh, 23(01), 157-169. Excerpt: https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Earth-age-and-thermal-history/more/Kelvin-1863-excerpts.pdf Thomson, W. (1897). The age of the Earth as an abode fitted for life.