Cosmos: Possible Worlds - Season 1 Episode 5

The Ship of the Imagination travels back in time to reveal 11th century Europe and North Africa during the golden age of Islam, when brilliant physicist Ibn al-Haytham discovered the scientific method and first understood how we see, and how light travels. Later, William Herschel discovers the infrared and the signature hidden in the light of every star, eventually unlocking one of the keys to the cosmos.