Thanks to Audible.com for supporting this video: http://www.audible.com/minutephysics Original video collaboration with Vsauce: https://www.youtube.com/watch?v=jN-FfJKgis8 Thanks to everyone who supports MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon supporters here: http://www.minutephysics.com/supporters.html Music by Nathaniel Schroeder, http://www.soundcloud.com/drschroeder REFERENCES Gravity & Spherical Shells: http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/sphshell.html More Shell Theorem: https://en.wikipedia.org/wiki/Shell_theorem Density inside the earth (Preliminary Reference Earth Model): https://en.wikipedia.org/wiki/File:RadialDensityPREM.jpg Gravitational acceleration inside the earth: https://en.wikipedia.org/wiki/File:EarthGravityPREM.jpg MinutePhysics is on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephysics And twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Created by Henry Reich