A long time ago (ca 260 BC) Eratosthenes used measurements of sun shadows in different places to calculate the cincumference of the earth. He got it pretty much right with an error of less than 4 %.
What if Eratosthenes had been trying to calculate the distance to the sun instead of the circumference of the earth using his method. Would it be possible? - Why or why not?
link: https://www.ancient.eu/Eratosthenes/
