who figured out the size of the earth
Eratosthenes He is best known for being the first person to calculate the circumference of the Earth, which he did by applying a measuring system using stadia, a standard unit of measure during that time period. His calculation was remarkably accurate. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy). Additionally, he may have accurately calculated the distance from the Earth to the Sun and invented the leap day.[4] He created the first map of the world, incorporating parallels and meridians based on the available geographic knowledge of his era.
Geographical centre of Earth In 1973, Andrew J. Woods, a physicist with Gulf Energy & Environmental Systems in San Diego, used a digital global map and calculated the coordinates on a mainframe system as 39°00′N 34°00′E﻿ / ﻿39.000°N 34.000°E﻿ / 39.000; 34.000﻿ (Geographical centre of all land surfaces on Earth (Woods 1973)), in modern Turkey, 1,000 km north of Giza[6][unreliable source?]