Author: Myda Mangla
Editor: Hira Islam
Abu Rayhan al-Biruni (973-ca. 1050) was a Muslim astronomer, mathematician, geographer, and historian. It is written then he was interested in literally everything; because of that, he is sometimes referred to as the Leonardo da Vinci of his time (Al-Hassani, 2012).George Sarton, the History of Science discipline founder, defined al-Biruni as “one of the very greatest scientists of Islam, and all considered one of the greatest of all times,” inarguably a universal genius. According to Bobojan Gafurov in his article on the Unesco Courier, Al Biruni “was so far ahead of his time that his most brilliant discoveries seemed incomprehensible to most of the scholars of his days” (Sparavigna, 2013). As a man that continues to be studied and honoured, we must acknowledge his brilliance and bring light to his discoveries and contributions when speaking of Islamic heritage. In this article, we will briefly go over the early life of Al Biruni and then dwell on the many contributions he made for the advancement of astronomy, math, and geography.
Al Biruni was born in Kath, Khwarizm, on September 4, 973, a country of the Khwarezmian civilization and several kingdoms. Today, it is fractioned and belongs to Uzbekistan, Kazakhstan and Turkmenistan (Sparavigna,2013). The information on Al-Biruni’s early life is hard to gather. However, he spent the first twenty-five years focused on his studies in Islamic laws, philosophy, mathematics, and astronomy. We know that because of his intelligence, rulers of his time would keep him in their company (Wahab,2021). After leaving his homeland, at the age of 22, al-Biruni wandered in Persia and Uzbekistan. During his time in Bukhara, he came in contact with Ibn Sina, otherwise known as Avicenna and exchanged views with him on various subjects (Wahab,2021). At the age of 25 in 998, Al Biruni wrote his first book known as “The Remaining Traces of Past Centuries” (Wahab,2021). Regarding his book, Al-Biruni explained that the aim was to establish, as accurately as possible, the time span of various eras. “The Remaining Traces of Past Centuries” also discusses the various calendar systems such as the Arabian, Greek and Persian and several others (Sparavigna,2013). Then, after Mahmud of Ghazni conquered the emirate of Bukhara, Al-Biruni moved in Ghazni (Sparavigna, 2013). Al-Biruni spent then his life serving Mahmud and later his son Mas’ud. He was the court astronomer and accompanied Mahmud during the invasion of the northwest of India, living there for a few years (Sparavigna, 2013). During this time, he wrote the “History of India.” Interesting to note that most of the works of Al-Biruni are in Arabic, although he wrote one of his masterpieces, the Kitab al-Tafhim, is Persian and Arabic (Sparavigna,2013).
As earlier mentioned, you cannot speak about topics such as astronomy, math, and geography without mentioning the significant contributions of Al Biruni. Al-Biruni dealt with Earth in many of his works. He proposed a method to measure its radius using trigonometric calculations (Sparavigna, 2013). He did this by measuring the high of a hill by measuring the angles subtended by the hill at two points a known distance apart. Then he climbed the hill and measured the angle of the dip of the horizon (Sparavigna,2013). “Using an Arabic mile equal to 1.225947 English miles, the Al-Biruni value of the radius was equal to 3928.77 English miles, which compares favourably, being different of 2%, with the mean radius of curvature of the reference ellipsoid at the latitude of measurement; this mean radius is of 3847.80 miles” (Sparavigna, 2013).
“Since then al-Biruni’s self-constructed instrument could have measured angles up to 10’ of the arc, the key to the precision of the measurement is a precise sine value, which he seems to have obtained from various Indian sources” (Sparavigna, 2013).
Furthermore, based on his calculations, Biruni also began to think about the possibility of the Earth revolving around the sun, an idea polymaths of that time would ignore (Tasci, 2020). Regardless of the lack of support, Biruni was so sure about his logic and instincts that he extensively wrote about the sun, its movements and the eclipse (Tasci, 2020). In addition, he invented astronomical instruments and described how the Earth rotated on an axis, making
accurate calculations of latitude and longitude. He noted down his theories and observations in his book, “Al-Athar Al-Baqiya.” He also wrote a treatise on how timekeeping occurred in 1000 C.E, the period is known as the Christian Era (Tasci,2020).
The Islamic Golden Age (8th-15th centuries) strongly promoted astronomy, and several scholars contributed to its development. Islamic astronomy had a significant influence on the astronomy of medieval Europe (Sparavigna, 2013). Many of the stars and astronomical terms we know today, such as alidade, azimuth, and almucantar, are still referred to by their Arabic names (Sparavigna, 2013). After 770, the Arabs adopted the sine function, inherited from Indian geometry, instead of chords of arc used in Greek trigonometry. One of the al-Biruni zijes contains a table giving the coordinates of six hundred places, almost all of them measured by al-Biruni himself (Sparavigna, 2013). Zij is the generic name of Islamic astronomical books that arrange parameters used for astronomical calculations concerning the positions of the moon, sun, planets, and stars (Sparavigna, 2013).
Furthermore, Al-Biruni denned the trigonometric functions of tangent and cotangent, inherited in a tentative form from the Indians (Sparavigna, 2013). Al-Biruni, help laid the foundation for modern trigonometry. In fact, through his findings, Al Biruni scientifically fixed the direction of Mecca from any point of the globe (Al-Hassani, 2012). Islam needed a way to figure out how to orient all sacred structures toward Mecca. The precise celestial mapping done by Al Biruni was necessary to find the right direction (qibla) toward the Kaaba. By the 9th century, the astronomers were often using trigonometry to determine the direction of Mecca from geographical coordinates, turning the qibla determination into a problem of spherical astronomy (Sparavigna, 2013).
In geography and geology, Al-Biruni contributed to geological eruptions and metallurgy (Tasci, 2020). Through his findings, Al Biruni explained the working of natural springs and artesian wells by the hydrostatic principle of communicating vessels (Tasci, 2020). In light of his scholarly work, he was called the founder of geodesy. His book Al-Athar Al-Baqiyah fi Qanun al-Khaliyah deals with ancient history and geography, and it was translated by Edward Sachau (Tasci,2020). Moreover, during his time in India, Al Biruni correctly identified the sedimentary nature of the Ganges River Basin (Al-Hassani, 2012). His great mineralogical work was called Treatises on How to Recognize Gems, and it made him a leading scientist in this area (Al-Hassani, 2012).
Keeping Islamic teaching as a cornerstone of his scientific finding, Biruni summarised his journey in the following way: “My experience in the study of astronomy and geometry and experiments in physics revealed to me that there must be a Planning Mind of Unlimited Power. My discoveries in Astronomy showed that there are fantastic intricacies in the universe which prove that there is a creative system and a meticulous control that cannot be explained through sheer physical and material causes” (Tasci, 2020).
Hundreds of centuries later, Al Biruni continues to inspire and educate people with his knowledge and findings. His dedication to his work was purely for the sake of learning and not for any material gains or possessions. When Sultan Masood sent him three camel-loads of silver coins in appreciation of his encyclopedic work “Al-Qanoon al-Masoodi,” (The Mas’udi Canon), Al-Biruni politely returned the royal gift saying, “I serve knowledge for the sake of knowledge and not for money” (Tasci,2020). After a remarkable life of research and exploration, Al Biruni passed away at the age of 77 in the year 1050 at Gazni, Afghanistan (Wahab,2021). May his knowledge continue to inspire the world around us, Ameen.
Sparavigna, A.C. (n.d.). “The Science of al-Biruni” Department of Applied Science and Technology, Retrieved Dec. 2013 from,
Salim T. S. Al-Hassani. (2012). “1001 Inventions: The Enduring Legacy of Muslim Civilization”, National Geographic
Tasci, U. N. (2020). Al-Biruni, the Golden Age of Islam’s ‘Universal Genius.’ Al-Biruni, the golden age of ISLAM’S ‘universal genius.’ Retrieved September 27, 2021, from https://www.trtworld.com/magazine/al-biruni-the-golden-age-of-islam-s-universal-genius-37622.
Tietz, Tabea. “Al-Biruni – Mathematician, Astronomer and Founder of Indology.” SciHi Blog, Retrieved September 4, 2021 from,
Wahab, A. (n.d.). “Al-Biruni,” in Science4Fun, Retrieved September 23, 2021 from,