The physics behind Einstein’s most famous equation

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Lindsay DeMarchi, Fabio Pacucci |

TED-Ed

• June 2025

Ever since Einstein published his Special Theory of Relativity, one equation has been the bane of humans hoping to explore the stars: E=mc². In addition to informing our understanding of gravity, space, and time, this formula implies that traveling at or beyond light speed is impossible. Why is that? Lindsay DeMarchi and Fabio Pacucci explain the physics behind this unbreakable speed limit. [Directed by Igor Ćorić, Artrake Studio, narrated by Addison Anderson, music by Cem Misirlioglu, Mikey Coltun].