Famous Scientists

Abū Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī (September 15, 973 in Kath, Khwarezm – December 13, 1048 in Ghazni) was a Persian Muslim polymath of the 11th century, whose experiments and discoveries were as significant and diverse as those of Leonardo da Vinci or Galileo, five hundred years before the Renaissance; al-Biruni was well-known in the Muslim world, but unlike some of his other Muslim contemporaries (such as Abulcasis, Alhacen, and Avicenna), al-Biruni’s name was little known in the Western world.

He was a scientist and physicist, an anthropologist, an astronomer and astrologer, an encyclopedist and historian, a geographer, a geodesist and geologist, a mathematician, a pharmacist and physician, a philosopher and Ash’ari theologian, a scholar and teacher, and a traveller, who contributed greatly to all of these fields. He was also the first Muslim scholar to study India and the Brahminical tradition, and has been described as the father of Indology, the father of geodesy, and “the first anthropologist”. Along with Geber and Ibn al-Haytham, al-Biruni was also one of the earliest leading exponents of the experimental method, and the first to conduct elaborate experiments related to astronomical phenomena.

George Sarton, the father of the history of science, described al-Biruni as:

“One of the very greatest scientists of Islam, and, all considered, one of the greatest of all times.”

A. I. Sabra desribed al-Biruni as:

“One of the great scientific minds in all history.”

The Al-Biruni crater, on the Moon, is named after al-Biruni.

Biography

He was born in Khwarazm (formerly north-eastern part of the Persian Samanid dynasty) presently in Khiva, Uzbekistan. He studied mathematics and astronomy under Abu Nasr Mansur.

He was a colleague of the fellow Persian Muslim philosopher and physician Abū Alī ibn Sīnā (Avicenna), the historian, philosopher and ethicist Ibn Miskawayh, in a university and science center established by prince Abu al-Abbas Ma’mun Khawarazmshah. He also travelled to South Asia with Mahmud of Ghazni (whose son and successor Masud was, however, his major patron), and accompanied him on his campaigns in India (in 1030), learning Indian languages, and studying the religion and philosophy of its people. There, he also wrote his Ta’rikh al-Hind (”Chronicles of India”). Biruni wrote his books in Arabic and his native language Persian, though he knew no less than four other languages: Greek, Sanskrit, Syriac, and possibly Berber.

He was buried in Ghazni in Afganistan.

Works

An illustration from Beruni’s Persian book. It shows different phases of the moon.

Biruni’s works number 146 in total. These include 35 books on astronomy, 4 on astrolabes, 23 on astrology, 5 on chronology, 2 on time measurement, 9 on geography, 10 on geodesy and mapping theory, 15 on mathematics (8 on arithmetic, 5 on geometry, 2 on trigonometry), 2 on mechanics, 2 on medicine and pharmacology, 1 on meteorology, 2 on mineralogy and gems, 4 on history, 2 on India, 3 on religion and philosophy, 16 literary works, 2 books on magic, and 9 unclassified books. Among these works, only 22 have survived, and only 13 of these works have been published. His extant works include:

• Critical study of what India says, whether accepted by reason or refused (Arabic تحقيق ما للهند من مقولة معقولة في العقل أم مرذولة) - a compendium of India’s religion and philosophy
• The Remaining Signs of Past Centuries (Arabic الآثار الباقية عن القرون الخالية) - a comparative study of calendars of different cultures and civilizations, interlaced with mathematical, astronomical, and historical information.
• The Mas’udi Canon (Persian قانون مسعودي) - an extensive encyclopedia on astronomy, geography, and engineering, named after Mas’ud, son of Mahmud of Ghazni, to whom he dedicated
• Understanding Astrology (Arabic التفهيم لصناعة التنجيم) - a question and answer style book about mathematics and astronomy, in Arabic and Persian
• Pharmacy - about drugs and medicines
• Gems (Arabic الجماهر في معرفة الجواهر) about geology, minerals, and gems, dedicated to Mawdud son of Mas’ud
• Astrolabe
• A historical summary book
• History of Mahmud of Ghazni and his father
• History of Khawarazm

Anthropology

Biruni has been described as “the first anthropologist”. He wrote detailed comparative studies on the anthropology of peoples, religions and cultures in the Middle East, Mediterranean and South Asia. Biruni’s anthropology of religion was only possible for a scholar deeply immersed in the lore of other nations. Biruni has also been praised by several scholars for his Islamic anthropology.

Astronomy

A statue of Biruni adorns the southwest entrance of Laleh Park in Tehran, Iran.

Instruments

In astronomy, al-Biruni invented and wrote the earliest treatises on the planisphere and the orthographical astrolabe, as well as the armillary sphere, and was able to mathematically determine the direction of the Qibla from any place in the world.^[15][16]

He also invented an early hodometer, and the first mechanical lunisolar calendar computer which employed a gear train and eight gear-wheels. These were early examples of fixed-wired knowledge processing machines.

Theories

Al-Biruni was the first to conduct elaborate experiments related to astronomical phenomena. He discovered the Milky Way galaxy to be a collection of numerous nebulous stars. In Khorasan, he observed and described the solar eclipse on April 8, 1019, and the lunar eclipse on September 17, 1019, in detail, and gave the exact latitudes of the stars during the lunar eclipse.

In 1030, Biruni discussed the Indian heliocentric theories of Aryabhata, Brahmagupta and Varahamihira in his Indica. Biruni noted that the question of heliocentricity was a philosophical rather than a mathematical problem.

In 1031, al-Biruni completed his extensive astronomical encyclopaedia Kitab al-Qanun al-Mas’udi (Latinized as Canon Mas’udicus), in which he recorded his astronomical findings and formulated astronomical tables. The book introduces the mathematical technique of analysing the acceleration of the planets, and first states that the motions of the solar apogee and the precession are not identical. Al-Biruni also discovered that the distance between the Earth and the Sun is larger than Ptolemy’s estimate, on the basis that Ptolemy disregarded the annual solar eclipses.

Abu Said Sinjari, a contemporary of al-Biruni, suggested the possible heliocentric movement of the Earth around the Sun, which al-Biruni did not reject. Al-Biruni agreed with the Earth’s rotation about its own axis, and while he was initially neutral regarding the heliocentric and geocentric models, he considered heliocentrism to be a philosophical problem. He remarked that if the Earth rotates on its axis and moves around the Sun, it would remain consistent with his astronomical parameters:

“Rotation of the earth would in no way invalidate astronomical calculations, for all the astronomical data are as explicable in terms of the one theory as of the other. The problem is thus difficult of solution.”

Will Durant wrote the following on al-Biruni’s contributions to astronomy:

“He wrote treatises on the astrolabe, the planisphere, the armillary sphere; and formulated astronomical tables for Sultan Masud. He took it for granted that the earth is round, noted “the attraction of all things towards the center of the earth,” and remarked that astronomic data can be explained as well by supposing that the earth turns daily on its axis and annually around the sun, as by the reverse hypothesis.”

Chemistry

Along with al-Kindi and Avicenna, al-Biruni was one of the first chemists to reject the theory of the transmuation of metals supported by some alchemists.

Earth sciences

Biruni made a number of contributions to the Earth sciences. In particular, he is regarded as the father of geodesy,^[7][26] and has made significant contributions to cartography, geography, and geology.

Cartography

By the age of 22, he had written several short works, including a study of map projections, Cartography, which included a method for projecting a hemisphere on a plane.

Geodesy and Geography

At the age of 17, Biruni calculated the latitude of Kath, Khwarazm, using the maximum altitude of the Sun. Biruni also solved a complex geodesic equation in order to accurately compute the Earth’s circumference, which were close to modern values of the Earth’s circumference. His estimate of 6,339.9 km for the Earth radius was only 16.8 km less than the modern value of 6,356.7 km.

John J. O’Connor and Edmund F. Robertson write in the MacTutor History of Mathematics archive:

“Important contributions to geodesy and geography were also made by al-Biruni. He introduced techniques to measure the earth and distances on it using triangulation. He found the radius of the earth to be 6339.6 km, a value not obtained in the West until the 16th century. His Masudic canon contains a table giving the coordinates of six hundred places, almost all of which he had direct knowledge.”

Geology

Among his writings on geology, Biruni wrote the following on the geology of India:

“But if you see the soil of India with your own eyes and meditate on its nature, if you consider the rounded stones found in earth however deeply you dig, stones that are huge near the mountains and where the rivers have a violent current: stones that are of smaller size at a greater distance from the mountains and where the streams flow more slowly: stones that appear pulverised in the shape of sand where the streams begin to stagnate near their mouths and near the sea - if you consider all this you can scarcely help thinking that India was once a sea, which by degrees has been filled up by the alluvium of the streams.”

History

Chronology

By the age of 27, in the year 1000, he had written a book called Chronology which referred to other works he had completed (now lost) that included one book about the astrolabe, one about the decimal system, four about astrology, and two about history.

He discussed more on his idea of history in another work, The Chronology of the Ancient Nations.

Indology

Until the 10th century, history most often meant political and military history, but this was not so with Persian historian Biruni (973-1048). In his Kitab fi Tahqiq ma l’il-Hind (Researches on India), he did not record political and military history in any detail, but wrote more on India’s cultural, scientific, social and religious history. Biruni is now regarded as the father of Indology.

Mathematics

He made significant contributions to mathematics, especially in the fields of theoretical and practical arithmetic, summation of series, combinatorial analysis, the rule of three, irrational numbers, ratio theory, algebraic definitions, method of solving algebraic equations, geometry, and the development of Archimedes’ theorems.

Medicine

Al-Biruni’s Kitab-al-Saidana was an extensive medical encyclopedia which synthesized Islamic medicine with Indian medicine. His medical investigations included one of the earliest descriptions on Siamese twins.

Physics

Celestial mechanics

In the celestial mechanics field of physics, al-Biruni described the Earth’s gravitation as:

“The attraction of all things towards the centre of the earth.”

He also discovered that gravity exists within the heavenly bodies and celestial spheres, and he criticized Aristotle’s views of them not having any levity or gravity and of circular motion being an innate property of the heavenly bodies.

Dynamics and kinematics

In the dynamics and kinematics fields of mechanics, al-Biruni was the first to realize that acceleration is connected with non-uniform motion, which is part of Newton’s second law of motion.

Natural philosophy

Al-Biruni and Abū Alī ibn Sīnā (Avicenna), who are regarded as two of the greatest polymaths in Persian history, were both colleagues and knew each other since the turn of the millenium. Al-Biruni later engaged in a written debate with Avicenna, with al-Biruni criticizing Aristotelian natural philosophy and the Peripatetic school, while Avicenna and his student Ahmad ibn ‘Ali al-Ma’sumi respond to al-Biruni’s criticisms in writing. Al-Biruni began by asking Avicenna eighteen questions, ten of which were criticisms of Aristotle’s On the Heavens, with his first question criticizing Aristotle’s reasons for denying the existence of levity or gravity in the celestial spheres and the Aristotelian notion of circular motion being an innate property of the heavenly bodies.

Al-Biruni’s second question criticizes Aristotle’s over-reliance on more ancient views concerning the heavens, while the third criticizes the Aristotelian view that space has only six directions. The fourth question deals with the continuity and discontinuity of physical bodies, while the fifth criticizes the Peripatetic school’s denial of the possibility of there existing another world completely different from the world known to them. In his sixth question, al-Biruni rejects Aristotle’s view on the celestial spheres having circular orbits rather than elliptic orbits. In his seventh question, he rejects Aristotle’s notion that the motion of the heavens begins from the right side and from the east, while his eighth question concerns Aristotle’s view on the fire element being spherical. The ninth question concerns the movement of heat, and the tenth question concerns the transformation of elements. The eleventh question concerns the burning of bodies by radiation reflecting off a flask filled with water, and the twelveth concerns the natural tendency of the classical elements in their upward and downward movements. The thirteenth question deals with vision, while the fourteenth concerns habitation on different parts of Earth. His fifteenth question asks how two opposite squares in a square divided into four can be tangential, while the sixteenth question concerns vacuum. His seventeenth question asks “if things expand upon heating and contract upon cooling, why does a flask filled with water break when water freezes in it?” His eighteenth and final question concerns the observable phenomenon of ice floating on water.

After Avicenna responded to the questions, al-Biruni was unsatisfied with some of the answers and wrote back commenting on them, after which Avicenna’s student Ahmad ibn ‘Ali al-Ma’sumi wrote back on behalf of Avicenna.

Optics

In optics, al-Biruni was one of the first, along with Ibn al-Haytham, to discover that the speed of light was finite. Al-Biruni was also the first to discover that the speed of light is much faster than the speed of sound.

Statics

In statics, al-Biruni measured the specific gravities of eighteen gemstones, and discovered that there is a correlation between the specific gravity of an object and the volume of water it displaces. He also introduced the method of checking tests during experiments, measured the weights of various liquids, and recorded the differences in weight between fresh water and salt water, and between hot water and cold water.

During his experiments, he invented the conical measure, in order to find the ratio between the weight of a substance in air and the weight of water displaced, and to accurately measure the specific weights of the gemstones and their corresponding metals, which are very close to modern measurements.

Theology

Islamic theology

Al-Biruni was a supporter of the Ash’ari school of Islamic theology. He assigned to the Qur’an a separate and autonomous realm of its own and held that:

“[the Qur'an] does not interfere in the business of science nor does it infringe on the realm of science.”

Comparative religion

He wrote works on both Islamic theology and Indian theology, and wrote on the topic comparative religion, comparing both religions. His comparisons included the following comparison between the Qur’an and the Indian religious scriptures in the “On the Configuration of the Heavens and the Earth According to [Indian] astrologers” chapter of the Indica:

“[The views of Indian astrologers] have developed in a way which is different from those of our [Muslim] fellows; this is because unlike the scriptures revealed before it, the Qur’an does not articulate on this subject [of astronomy], or any other [field of] necessary [knowledge] any assertion that would require erratic interpretations in order to harmonize it with that which is known by necessity.”

“[In contrast, the religious and transmitted books of the Indians do indeed speak] of the configuration of the universe in a way which contradicts the truth which is known to their own astrologers.”

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