Pony images used are from MLP:FiM (by Hasbro).
The original video (by Vsauce):    • What Is The Speed of Dark?  
Check out other cool videos on the Vsauce channel:    / vsauce1  
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COPYRIGHTS: FAIR USE, Title 17, US Code (Sections 107-118 of the copyright law): All media in this video is used for a limited and transformative purpose under terms of fair use. All footage, music & images used belong to their respective companies.