I have previously written several blogs on Islamic science and how it not only fostered the right conditions, but provided a firm foundation for the emergence of the European renaissance. I decided to dig a little deeper, to see if there was clear, concrete evidence for Islamic science paving the way for the emergence of—in this case—modern astronomy and physics, during the renaissance.
I took an astronomy class at a nearby community college to supplement my knowledge and to see if there was any mention of the supposed contributions of Muslims to the advancement of astronomy. When I had a conversation with the instructor of this class; it was telling when he said while interested in the subject, he did not know enough about the history of Islamic contributions to astronomy to include them in the syllabus.
The Ptolemaic Universe and Copernicus
For a thousand years, the western view of the universe was shaped by Ptolemy, who lived about five centuries after Aristotle, and who advocated the idea that the earth was stationary, and that all the heavenly bodies, including the sun, revolved around it.
It wasn’t until the early 16th century that Copernicus—a Polish cleric—upended the scientific world by publishing his book De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres) laying out the heliocentric theory that sun was at the center of the universe and that the planets revolved around it.
However when one studies popular text books in the West on this subject, no mention is made on how Copernicus came up with his ideas and not much is said about time period between the 2nd and 15th centuries regarding advances in astronomy. As an example, in the text book for my class, ‘Stars and Galaxies’ , in Chapter 4, ‘The Origin of Modern Astronomy’ there is almost no mention of the contributions of Muslim astronomers, which gives the impression that astronomy before Copernicus was ancient and not scientific, but rather crude and mystical, and that only after Copernicus did astronomy became a precise science. At the end of this chapter it states: “the scientific revolution began when Copernicus made humanity part of the universe…”. My subsequent research has made me believe that this type of accepted analysis is not only incomplete but in many ways incorrect.
Let’s delve into the meat of this subject.
Astronomy, Islam and the Qur’an
For most civilizations during their golden age, the science of astronomy provided the means for the study of the heavens, and the Islamic civilization was no exception; astronomy was of great interest to the Islamic scientists, scholars and the Caliphs that also led to the development of other sciences.
For Muslims, there was also a practical benefit of fulfilling their sacred obligation of prayer and fasting as stated in their holy book, the Qur’an, which involved knowing the exact times for these duties as well as the exact location of the House of Abraham in Mecca, also known as the “Qibla”. The end result was that they brought standards of accuracy and precision in astronomy unheard of before: their sun dial was accurate within minutes, their calculated size of earth was within one percent and the trigonometry tables were accurate to three decimal places .
The Qur’an also provided tantalizing clues for the Muslims as to the nature of the heavens; here are some examples from the Qur’an:
“The sun moves in a fixed place and each star moves in its own heaven (Surih 36:37)”
“It is He Who created the night and the day, and the sun and the moon. All (the celestial bodies) swim along, each in its rounded course” (21:33).
“It is not permitted for the sun to catch up to the moon, nor can the night outstrip the day. Each just swims along in its own orbit” (36:40).
“He created the heavens and the earth in true proportions. He makes the night overlap the day, and the day overlap the night. He has subjected the sun and the moon to His law; each one follows a course for a time appointed…” (39:5).
“The sun and the moon follow courses exactly computed” (55:5).
While some in the West thought of the earth as a flat object at the center of universe, the Muslims took earth’s sphericity for granted . But ironically, even many Muslims of that time tried to explain away what the Quran said regarding the earth moving around the sun, since it was contrary to the accepted norm—the Ptolemaic system .
Copernicus and the Islamic connection
The view of the modern academic world regarding Islamic influence on Copernicus was constricted, and confined to a few references by him from Islamic authors whose work was translated into Latin. One of the Muslim astronomers that Copernicus quoted, including his precise astronomical data, was Al-Battani who was born in the 9th century around Turkey. He was a Muslim astronomer, astrologer, and mathematician. He introduced a number of trigonometric relations in his Kitāb az-Zīj and he famously determined the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds. Al-Battānī figured out that our solar system was moving through space, significantly improved upon Ptolemy’s theories, and discovered that the direction of the Sun’s apogee, as recorded by Ptolemy, was changing . Actually, many astronomers of that time documented the elliptical nature of planetary orbits, hinting that the earth may be rotating around the sun .
It was in the 1950s that, due to a series of discoveries, Copernicus’s use of an important mathematical concept in his book was shown to be derived from the work of a Persian scholar, Al-Tusi. This is called the Tusi couple. The Tusi couple challenges Ptolemy, and replaces a sphere rotating around an arbitrary point in space with two nested circles rotating around each other in such a way to eliminate Ptolemy’s equant. This mathematical system in its entirety found its way to Copernicus’s book 300 years later.
Below is a snapshot of Al-Tusi’s theory side by side Copernicus’s book outlining the same theory. The similarity is stunning.
Below is a visual description of the ‘Tusi Couple’.
For a more in-depth analysis refer to a paper titled: Coprenicus and his Islamic Predecessors: Some Historical Remarks  or Islamic Science and the Making of the European Renaissance.
The story of Al-Tusi does not end there. The Maragheh observatory in North West of Iran, considered to be the largest and most prestigious observatories of its time, was built under his directorship for the purpose of establishing accurate astronomical tables.
Other Islamic scholars
Omar Khayyam—who is best known for his poetry and algebra—established a calendar that calculated the Persian New Year to unheard of accuracy that errs one day in 5000 years.
Yet another outstanding Persian scholar was Al-Biruni, he was well versed in physics, mathematics, astronomy, and natural sciences, and also distinguished himself as a historian, chronologist and linguist. Quoting Wikipedia :
“In his description of Sijzi’s astrolabe he hints at contemporary debates over the movement of the earth. He carried on a lengthy correspondence and sometimes heated debate with Ibn Sina, in which Biruni repeatedly attacks Aristotle’s celestial physics: he argues by simple experiment that vacuum must exist; he is “amazed” by the weakness of Aristotle’s argument against elliptical orbits on the basis that they would create vacuum; he attacks the immutability of the celestial spheres; and so on…
In his major extant astronomical work, the Mas’ud Canon, he regards heliocentric and geocentric hypotheses as mathematically equivalent but heliocentrism as physically impossible, yet approves of the theory that the earth rotates on its axis. He utilizes his observational data to disprove Ptolemy’s immobile solar apogee. More recently, Biruni’s eclipse data was used by Dunthorne in 1749 to help determine the acceleration of the moon and his observational data has entered the larger astronomical historical record and is still used today in geophysics and astronomy.”
Al-Khwarizm, al-Farghani, Abd al-Rahman al-Sufi, al-Zarkali and Ibn Yunus were also some of the great minds of Islamic science and astronomy.
The above facts are just the tip of the iceberg, and yet is compelling evidence of the outstanding contribution of the Islamic scholars in the field of astronomy.
It is clear that the Muslims did a lot more than the popular belief that they just translated works of the Greek philosophers to Latin. They found serious flaws on and improved on Ptolemy’s theory on planetary motion and developed theories consistent with the laws of physics. This was made possible by creation and use of new mathematics, algebra and trigonometry. They developed new and advanced – or perfected existing – astronomical instruments, including the astrolabe and the sextant, thus setting the standard for the critically needed precise measurements of latitude and longitude, time, and location of the stars and planets, which were used by the Western scholars centuries later. These instruments and measurements, as well as the development of the magnetic needle, were also important tools for significantly advancing navigation techniques on land and sea.
Regarding observatories Dr. Ajram in his wonderful book ‘the Miracle of Islamic Science’ states :
“The concept of observatory as a scientific institution was an Islamic invention…How, then, can Isaac Asimov, with good conscience, claim that the first ‘scientific’ observatories were built in the 16th through 17th century in Europe?”
Having researched to some degree the influence of Islam on modern Western civilization (even though I am not a Muslim), I was not surprised that there was little mention in my astronomy class and the recommended textbook regarding the above mentioned facts. I find this unfortunate. With the emergence of search engines and the web, massive amount of information is at our fingertips; what students and seekers need are proper insights and ideas for research. I highly recommend watching this outstanding BBC documentary on Islamic Astronomy .
A final note: I felt proud when I found out that Persia (or Iran) was a hotbed for astronomers of that time, and many of the scholars mentioned are Persian, my nationality. [Update: I shared the documentary links with the instructor of my class and he told me today that he is already aware that the textbook overlooks contributions from Islamic scholars and has been working on adding Islamic contributions to astronomy in his lectures]
====================== References ========================
Abdu’l-Baha, Some Answered Questions, p. 23
 The miracle of Islamic science, Dr K Ajram p. 56-57
 Stars and Galaxies, Seeds & Backman, 8th edition
 The miracle of Islamic science, Dr K Ajram p. 46
 The miracle of Islamic science, Dr K Ajram p. 49-51
 Islamic Science and the Making of the European Renaissance by George Saliba