The scholar who wrote on everything — and learned Sanskrit to do it

The polymath al-Biruni (973–1048) is credited with some 146 works spanning astronomy, mathematics, geography, mineralogy, pharmacology and history, and he learned Sanskrit to research a detailed study of India. Using trigonometry and observations from a mountaintop, he estimated the Earth's radius at about 6,340 km — within roughly 1% of the modern figure of 6,371 km.

One of many fact-checked wonders across eight traditions at The Spring of Wisdom.