Medieval Muslim World
At some time in the
9th century, with scholars like
Al-Battani, the
Muslim World was leading in
astronomical knowledge, and the sphericity of the Earth was consequently a well known fact. Around 830 CE, Caliph
al-Ma'mun commissioned a group of astronomers to measure the distance from Tadmur (
Palmyra) to
al-Raqqah, in modern Syria. They found the cities to be separated by one degree of latitude and the distance between them to be 66 2/3 miles and thus calculated the Earth's circumference to be 24,000 miles.
[38] Ibn Taymiya (died 1328 CE), said:
"Celestial bodies are round - as it is the statement of astronomers and mathematicians - it is [likewise] the statement of the scholars of the Muslims; as Abul-Hasan ibn al-Manaadi, Abu Muhammad Ibn Hazm, Abul-Faraj Ibn Al-Jawzi and others have quoted: that the Muslim scholars are in agreement (that all celestial bodies are round). Indeed Allah has said: And He (i.e., Allah) it is Who created the night and the day, the sun and the moon. They float, each in a Falak. Ibn Abbas says: A Falaka like that of a spinning wheel. The word 'Falak' (in the Arabic language) means "that which is round." [39]
Many Muslim scholars declared a mutual agreement (
Ijma) that celestial bodies are round. Some of them are:
Ibn Hazm (d. 1069),
Ibn al-Jawzi (d. 1200), and
Ibn Taymiya (d. 1328). The later belief of Muslim scholars, like
Suyuti (d. 1505) that the earth is flat represents a deviation from this earlier opinion .
[40]
The Muslim scholars who held to the round earth theory used it in an impeccably Islamic manner, to calculate the distance and direction from any given point on the earth and
Mecca. This determined the
Qibla, or Muslim direction of prayer. Muslim mathematicians developed
spherical trigonometry which was used in these calculations.
[41] Ibn Khaldun, in his famous
Muqaddimah, clearly says the world is spherical.
There is also a verse in the Quran [79:30] which some modern English translations give as "He made the earth egg-shaped"
[42] which suggests that the Earth was not believed to be flat. Most translations ("And after that He spread the earth") suggest that this verse can be interpreted to support the flat Earth theory.