The flat myth and the ancient curve
The spin that squashed the poles
The lumpy gravity of the geoid
Mapping a round world on a flat screen
YOUR GOAL
Master of The lumpy potato we call home
007skaty At Fort Nandana in Pakistan, Al-Biruni used trigonometry and a mountain's horizon dip angle to measure Earth's radius
007skaty Glowing mathematical diagrams and constellations surround a spherical Earth in the ancient Indian sky.
Eratosthenes' nickname: The ancient Greek scholar Eratosthenes was nicknamed 'Beta' because his contemporaries thought he was the second-best in every field of study.
The quality, state, or condition of being spherical. Eratosthenes calculated Earth's sphericity around 240 BCE, debunking the historical misconception of medieval flat-Earth beliefs.
What ancient unit of distance did Eratosthenes use to calculate the Earth's circumference?
In which modern country did Al-Biruni conduct his famous mountain-peak measurement of the Earth?
Which Indian astronomer calculated the Earth's circumference in 499 CE with an error of less than 1%?
What angle did Eratosthenes measure the sun's shadow to be in Alexandria on the summer solstice?
Which ancient city, now called Aswan, had a famous well where the sun cast no shadow at noon on the summer solstice?