...or why do we live on an onion made of magma?
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Thanks to Miles Traer and Mike Osborne for geophysics help on this one!
Why does Earth have a liquid core, and how do we know?
http://scienceblogs.com/startswithabang/2011/09/28/why-does-the-earth-have-a-liqu/
How many pennies would you have to stack to melt the one on the bottom? http://www.reddit.com/r/askscience/comments/2g8jj9/how_many_pennies_need_to_be_stacked_before_the/
Why are the inner planets rocky and the outer ones are gas giants?
http://www.quora.com/Why-are-the-inner-planets-rocky-and-the-middle-planets-large-gas-giants
Produced for PBS Digital Studios
Joe Hanson - Host and writer
Joe Nicolosi - Director
Amanda Fox - Producer, Spotzen IncKate Eads - Associate Producer
Katie Graham - Director of Photography
Andrew Matthews - Editing/Motion Graphics
John Knudsen - Gaffer
Dalton Allen - Post-production Intern
Theme music:
"Ouroboros" by Kevin MacLeod
Stock images via Shutterstock
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