Al-Biruni

Al-Biruni (973-1048) was one of the greatest Muslim scholars of the 11th century. He made amazing contributions to astronomy, mathematics, physics, and geography.  He accurately calculated the Earth's radius centuries before modern scientists!  He also suggested that the Earth rotates on its axis, an idea very advanced for his time.  

Where Al-Biruni measured the radius of the Earth?

While on a mountain near Nandana (Pakistan), he used an astrolabe and the law of sines to estimate the Earth's radius as 6,339.9 km, which was only 16.8 km off the modern value. 

Not only a scientist!

He is the father of comparative religion. He studied different religions and cultures through his famous works like Kitab al-Hind. His deep search for knowledge showed the true Islamic spirit of learning and respect.