William Thomson Kelvin (1824 - 1907) who proposed the absolute or Kelvin temperature scale. He also established the second law of thermo-dynamics. He was brilliant. But he wasn't perfect. W. & D. Downey/Getty Images hide caption

toggle caption W. & D. Downey/Getty Images

Pathologist Thomas Harvey took dozens of photos of Einstein's brain. This one shows that Einstein's prefrontal cortex (associated with higher cognition and memory) is unusually convoluted. On the right side of the brain there are four large ridges, where most people have only three. Brain(2012)/National Museum of Health and Medicine hide caption

toggle caption Brain(2012)/National Museum of Health and Medicine

A detail from what is thought to be one of only three existing manuscripts containing Einstein's most famous formula about the relationship between energy, mass and the speed of light — in his handwriting. Sean Carberry/NPR hide caption

toggle caption Sean Carberry/NPR

The Two-Way

Brilliant Idea: More Than 80,000 Of Einstein's Documents Going Online

They include work related to his most famous formula — E=mc² — and personal papers, such as letters to and from his former mistresses.

Listen Loading… 3:31
  • Playlist
  • Download
  • Embed
    <iframe src="http://www.npr.org/player/embed/148932592/148939339" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">

NPR thanks our sponsors

Become an NPR sponsor