In his Book of Optics, written in Cairo around 1011-1021, the Basra-born scholar Ibn al-Haytham rejected the idea, inherited from Euclid and Ptolemy, that the eye sends out rays. Instead, he argued, light reflected by objects enters the eye. Above all, he backed his claims with methodical experiments, notably using a camera obscura. Translated into Latin around 1200, his work shaped European optics up to Kepler. UNESCO celebrated its millennium in 2015.
Around 2300 BCE, Enheduanna, daughter of King Sargon of Akkad, became high priestess of the Moon god at Ur. She composed hymns to the goddess Inanna and put her name to them. She is the oldest person identified as the author of a literary work, about 1,500 years before Homer.
Squeeze Earth's 4.5 billion years into a single 24-hour day. Homo sapiens shows up around 11:59:54 p.m., roughly six seconds before midnight. All of written history, from Sumerian tablets to today, fits into the final tenth of a second. A cosmic blink.