Al-Biruni: Who calculated Earth’s Radius


Al-Biruni, born in 973 in Khwarezm (now part of Uzbekistan), was a polymath whose intellectual brilliance transcended borders and disciplines. As a Khwarazmian Iranian scholar, he embarked on a remarkable journey of exploration, mastering a diverse range of fields, including astronomy, mathematics, physics, geography, history, anthropology, and comparative religion.

Unveiling the Life

Hailing from the city now known as Beruniy, al-Biruni’s early years set the stage for a life dedicated to the pursuit of knowledge. His exceptional intellect and insatiable curiosity propelled him to become a master of various sciences, placing him among the brightest minds of his time. From astronomy to comparative religion, al-Biruni’s thirst for understanding knew no bounds.

The Work that Shaped the World

Al-Biruni’s contributions to scientific knowledge were nothing short of revolutionary. By applying the principles of trigonometry and algebra, he calculated the Earth’s radius with remarkable precision, yielding results that were astonishingly close to modern measurements. Furthermore, al-Biruni boldly challenged the prevailing geocentric worldview, asserting that the Earth rotated on an axis around the Sun. These groundbreaking ideas paved the way for future advancements in astronomy and cosmology.

Also read- Al-Biruni: The Accomplishments and Contributions of a Renowned Muslim Scholar

Groundbreaking Scientific Achievements

  • Calculating the Earth’s Radius: Explain Al-Biruni’s innovative use of trigonometry and algebra to calculate the Earth’s radius, yielding remarkably accurate results that were close to modern measurements.
  • Challenging Geocentrism: Explore Al-Biruni’s assertion that the Earth rotated on an axis around the Sun, challenging the prevailing geocentric worldview of his time and paving the way for advancements in astronomy.
  • Contributions to Indology: Discuss Al-Biruni’s comprehensive treatise, “The History of India,” and his profound understanding of Indian culture, religion, and society, which laid the foundation for cross-cultural dialogue and knowledge exchange.

Journey into Indian Culture

A pivotal chapter in al-Biruni’s life unfolded during his captivity in India, under the patronage of Mahmud of Ghazni. It was during this time that he immersed himself in the intricacies of Indian culture, religion, and society. His comprehensive treatise, Tārīkh al-Hind (“The History of India”), stands as a testament to his profound understanding of Hindu faith and practices. Al-Biruni’s work in Indology laid the foundation for cross-cultural dialogue and fostered a greater appreciation of the richness of human civilization.

Few book’s written by him

  1. “Kitab al-Tafhim” (Book of Instruction): An influential work that covers various branches of knowledge, including astronomy, mathematics, geography, and natural philosophy.
  2. “Tahqiq ma li’l-Hind” (The Indica): A comprehensive treatise on Indian culture, religion, science, and society. It showcases Al-Biruni’s deep understanding of Indian civilization and is considered a significant contribution to the field of Indology.
  3. “Kitab al-Jamahir fi Marifat al-Jawahir” (Book of Precious Stones): A treatise on minerals, gems, and their properties.
  4. “Al-Qanun al-Mas’udi” (The Mas’udic Canon): A voluminous encyclopedic work that covers a wide range of subjects, including astronomy, geography, mathematics, and history.
  5. “At-Tafhim li Awa’il Sina’at at-Tanjim” (Introduction to the Elements of Astrology): A foundational work on astrology.
  6. “Kitab al-Saydalah” (Book of Pharmacy): A pharmacological work discussing medicinal plants and their uses.
  7. “Asar al-Baghdad” (The Monuments of Baghdad): A historical and architectural account of the city of Baghdad.
  8. “At-Tarikh al-Hind” (The History of India): A significant historical work that provides valuable insights into Indian history, culture, and civilization.

Friendship, Rivalry, and Intellectual Exchange

Al-Biruni’s intellectual journey was enriched by his friendship and rivalry with the esteemed scholar Ibn Sina. These two luminaries engaged in passionate debates, spurring each other to new heights of intellectual exploration. From discussions on light and heat to motion and astronomy, their exchange of ideas pushed the boundaries of scientific inquiry and left an indelible mark on the history of scholarship.

A Legacy Carved in Time

Al-Biruni’s linguistic acumen allowed him to delve into the works of ancient Greek and Indian scientists, enabling him to translate and interpret their profound insights. This multilingual genius not only preserved valuable knowledge but also expanded upon it, enriching the tapestry of human understanding. Even in his later years, as he resided in Ghazni (now in Afghanistan), his thirst for knowledge remained unquenched.

Al-Biruni’s legacy as al-Ustadh, “The Master,” endures to this day. His scholarly objectivity, universal genius, and unwavering pursuit of wisdom continue to inspire scholars and thinkers across generations. The impact of his contributions can be felt in the realms of science, culture, and intercultural dialogue, reminding us of the boundless potential of the human mind.


In the annals of intellectual history, al-Biruni shines as a beacon of inspiration and discovery. His relentless pursuit of knowledge, groundbreaking scientific achievements, and cultural exploration have left an indelible mark on human civilization. As we reflect upon the life, work, and enduring legacy of this medieval scholar, let us be inspired to embrace curiosity, foster intellectual exchange, and strive for greatness in our own pursuits. Al-Biruni’s story is a testament to the enduring power of knowledge and the transformative impact of a single inquisitive mind.