In a feature article for History Today, S. Frederick Starr of the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University, looks at the claimants to the discovery of the New World, including Abu Raihan al-Biruni, an Islamic scholar from Central Asia, who "may have discovered the New World centuries before Columbus – without leaving his study."
Abu Raihan al-Biruni was a 10th century scholar from the Aral Sea in what is now Uzbekistan. In a castle near Islamabad, Biruni "devised a new technique, which involved careful observation, spherical trigonometry and the application of the law of sines. Besides being far simpler than using two distant points on flat land, this method produced a measure of the earth’s circumference that was a mere 10.44 miles less than the definitive modern measurement." These calculations were available to Columbus and other early explorers.