Aryabhatiya I.5 (499 CE) gives Earth's diameter as 1,050 yojanas. The yojana-to-modern-units conversion is genuinely disputed (estimates range from 5 to 8 miles per yojana), but with the most-cited mid- period value of ~7.5 mi, Earth's diameter comes out to 7,875 miles — within 1% of the modern 7,917. Pre-telescopic, by a 23-year-old in Kusumapura.