geometry

Around 270 BC, Aristarchus of Samos used lunar eclipses and the half-moon angle to calculate the Sun's distance and size — and concluded the Earth orbits the Sun, not the reverse.

Around 240 BCE, Eratosthenes measured Earth's circumference using two sticks and shadows. Here is exactly how he did it — and why the result was nearly perfect.

Pythagoras founded a secretive mathematical cult, gave his name to a theorem the Babylonians already knew, and may have had a disciple drowned for proving irrational numbers exist.

Maryam Mirzakhani's life, discoveries, and verified quirks: painting math on the floor, two IMO gold medals, the Fields Medal in 2014, and dying at 40 of breast cancer.

A single number — 1.618 — is claimed to appear in sunflowers, seashells, and the Mona Lisa. Some of that is real math. Most of it is myth. Here's how to tell the difference.

Around 240 BCE, Greek mathematician Eratosthenes used only sunlight, shadows, and geometry to calculate Earth's circumference with remarkable accuracy. A timeless example of clever scientific thinking.