When the Sun Revolved Around the Earth
Dr. Nazeer Ahmed
There was no single moment when Islamic civilization lost its scientific and technological leadership. Rather, it was a long, uneven process marked by several well-known milestones: the misunderstood al-Ghazzali’s dialectical critique of the philosophers around 1100 CE; the Mongol invasions that devastated the heartlands of learning between 1219 and 1263; the failure to adopt the printing press for nearly three centuries after its introduction in Europe; and the neglect of naval technology at precisely the moment when control of the seas determined global power. Each of these episodes weakened the scientific initiative of Muslim societies.
Yet there is another, less discussed but equally consequential milestone: the failure of Muslim scholarship to break decisively from a geocentric model of the cosmos between roughly 1500 and 1700 CE. This intellectual hesitation—remaining within an Earth-centered universe long after its mathematical strains were evident—proved decisive in determining which civilization would step into the modern scientific age.
It is difficult for us today to grasp that the Mughal, Safavid, and Ottoman empires—immensely wealthy, administratively sophisticated, and culturally confident—shared a cosmology in which the Sun revolved around a stationary Earth. For Muslim scholars, the Earth-centered universe was not seriously abandoned until the nineteenth century. By then, Europe had already forged a century-long lead in science, technology, and industrial power.
To understand how this happened, we must revisit a critical juncture in history.
The Shock of Baghdad and the Survival of Scholarship
The fall of Baghdad to Hulagu Khan in 1258 was a civilizational catastrophe. Scholars were killed, libraries destroyed, and centuries of accumulated learning were lost. The House of Wisdom—symbol of the Abbasid intellectual flowering—was wiped out. Few events rival this destruction in its long-term consequences for global knowledge.
And yet, Islamic civilization demonstrated remarkable resilience. One of the most brilliant mathematicians and astronomers of the age, Nasir al-Din al-Tusi, escaped the devastation, took refuge in the mountains of Alamut, and eventually found his way into Mongol service. After the fall of Alamut in 1256, al-Tusi entered Hulagu’s court and quickly earned trust—not as a religious ideologue, but as a disciplined scholar who could strengthen imperial authority. He persuaded Hulagu that astronomy and astrology were tools of governance, prestige, and military planning.
As a result, the Maragha Observatory was founded in 1261, becoming one of the most important scientific institutions of the medieval world.
Geocentrism and the Greek Inheritance
By this time, Muslim astronomy had long adopted geocentrism, inherited from Greek science, particularly from Ptolemy. Since the Mu‘tazilite period in the eighth and ninth centuries, Greek natural philosophy—especially Aristotle’s physics—had been absorbed into Islamic intellectual life. According to this framework, the Earth stood immobile at the center of the universe, while the heavens moved in perfect, uniform circles around it.
This model was never accepted uncritically. Scholars such as Ibn Sina, al-Biruni, and Ibn al-Haytham recognized deep inconsistencies in Ptolemy’s system. Ibn al-Haytham, in particular, demonstrated that Ptolemy’s mathematical devices lacked physical realism. Yet despite these critiques, Muslim scholarship did not abandon the Earth-centered cosmos.
Why? Because astronomy, physics, and metaphysics were deeply interwoven. Aristotelian physics held that heavy bodies naturally came to rest at the center of the universe, while celestial bodies—made of a different, incorruptible substance—moved eternally in circles. Over time, a theological overlay emerged that presented the cosmos as finite, ordered, hierarchical, and Earth-centered, with the heavens rotating above like a dome.
The Triumph—and Limitation—of Mathematical Genius
Within this framework, Nasir al-Din al-Tusi made one of the most important mathematical innovations in the history of astronomy: the Tusi Couple. This ingenious construction generated linear oscillatory motion from two uniform circular motions, allowing astronomers to eliminate Ptolemy’s awkward equants while preserving circular motion. It reconciled observation with geometry without violating Aristotelian principles.
The Tusi Couple was revolutionary. It anticipated later developments in kinematics and even modern mechanical linkages. But it was revolutionary within a geocentric paradigm.
Al-Tusi’s work was refined by Ibn al-Shatir of Damascus in the fourteenth century. Ibn al-Shatir eliminated equants entirely and produced planetary models that matched observation with astonishing accuracy. His lunar and planetary models are mathematically equivalent to those later proposed by Copernicus—except for one crucial difference: the Earth remained fixed.
In the fifteenth century, Ulugh Beg, the Timurid ruler of Samarkand, built a monumental observatory and produced the Zij-i Sultani, one of the most accurate star catalogs of the premodern era. Again, the framework was geocentric.
These scholars pushed Earth-centered astronomy to its limits. But they did not cross the conceptual threshold that would have required abandoning Aristotelian physics itself.
The Civilizational Fork in the Road
By around 1500 CE, Islamic and European civilizations stood before the same scientific horizon. Both had access to advanced mathematical astronomy. Both struggled with the growing complexity of Ptolemaic models. But they responded differently.
In Europe, the Renaissance had unleashed a restless intellectual energy. Copernicus, drawing directly on the mathematical tools developed by Muslim astronomers—including models traceable to Ibn al-Shatir—made a radical move: he allowed the Earth to move. By placing the Sun at the center, planetary motions became simpler, more elegant, and more orderly.
Copernicus did not yet have a new physics to justify this move. He retained circular orbits and published cautiously, presenting heliocentrism as a mathematical convenience.
But the conceptual barrier had been breached.
From Galileo to Newton
Two ancient assumptions still had to fall: that motion required continuous force, and that heavy bodies must remain at rest. Galileo Galilei shattered both. Using telescopic observations, he confirmed the phases of Venus and the moons of Jupiter—direct evidence against geocentrism. Through experiments, he demonstrated inertia and showed that all bodies fall at the same rate, regardless of weight.
The Church, deeply invested in geocentrism, resisted fiercely. Persecuted and forced to recant, Galileo nonetheless changed the trajectory of science.
Building on precise observational data from Tycho Brahe, Johannes Kepler abandoned circular orbits altogether and demonstrated that planets move in ellipses, with the Sun at one focus. Finally, Isaac Newton unified terrestrial and celestial motion under universal laws of motion and gravitation, published in 1687.
With Newton, the cosmos became intelligible as a single, law-governed system. This intellectual breakthrough laid the foundation for modern engineering, industry, and technological civilization.
Why the Muslim World Hesitated
What is most striking is how close Muslim astronomers came to heliocentrism—and yet did not embrace it. The reason lies not in intelligence or mathematical ability, but in purpose.
Muslim astronomy had become primarily instrumental: determining prayer times, fixing the qibla, regulating calendars, and aiding navigation. It was no longer pursued as a path to uncovering the physical structure of nature itself. Nature, which the Qur’an presents repeatedly as a sign (ayah) pointing to a higher reality, was instead approached through inherited Greek metaphysics.
Islamic scholarship had become a custodian of Aristotle rather than a challenger of his assumptions.
The Cost of Delay
Newtonian physics transformed Europe and, through industrialization, reshaped the world. The Muslim world, slow to recognize this shift, initially rejected modern science as foreign and culturally threatening. Reformers such as Sir Syed Ahmad Khan of Aligarh faced intense opposition well into the last quarter of the nineteenth century.
Only now, in the twenty-first century, is the Islamic world reluctantly coming to terms with the centrality of science, technology, engineering, and mathematics—not merely for material prosperity, but for civilizational survival.
The tragedy is not that Muslims once believed the Sun revolved around the Earth. The tragedy is that, when the moment came to let the Earth move, they hesitated—while others stepped forward and changed the world.
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A Chronology
- al-Khwarizmī 780 – 850 CE
Universal mathematician, inventor of algorithms; Founder of Islamic mathematical astronomy; his Zīj al-Sindhind introduced Indian and Greek astronomical methods into the Islamic world and later into Europe. - al-Battānī 858 – 929 CE
One of the greatest observational astronomers; refined values for the solar year, obliquity of the ecliptic, and planetary motions. Strong influence on Copernicus. - ibn Qurra 826 – 901 CE
Worked on planetary theory, precession of the equinoxes, and translations of Greek astronomy; contributed to early critiques of Ptolemy. - ʿAbd al-Raḥmān al-Ṣūfī 903 – 986 CE
Author of Book of the Fixed Stars; improved star magnitudes and constellations, identified the Andromeda Galaxy centuries before Europe. - Ibn Yūnus c. 950 – 1009 CE
Produced the highly accurate Hakemite Tables; used pendulum-like timing methods and extremely precise solar and lunar observations. - Abū Rayḥān al-Bīrūnī 973 – 1048 CE
Universal scientist; wrote extensively on astronomy, Earth’s rotation, trigonometry, and planetary distances; measured Earth’s radius with remarkable accuracy. - Ibn al-Haytham (Alhazen) 965 – 1040 CE
Best known for optics, but also a major critic of Ptolemaic astronomy; insisted that astronomical models must correspond to physical reality, not just mathematics. - Naṣīr al-Dīn al-Ṭūsī 1201 – 1274 CE
Founder of the Maragha Observatory; invented the Ṭusī Couple, a key mathematical device later used in Copernican models. - Ibn al-Shāṭir 1304 – 1375 CE
Developed planetary models; two hundred years later, Copernicus developed similar models (without heliocentrism); eliminated the equant while preserving observational accuracy. - Ulugh Beg 1394 – 1449 CE
Timurid king-astronomer; built the Samarkand Observatory; produced one of the most accurate star catalogs before the telescope. - Taqī al-Dīn Muḥammad ibn Maʿrūf 1526–1585 CE
Ottoman astronomer; built the Taqi Uddin observatory in Istanbul; Designed and built high-precision mechanical clocks with minutes and seconds divisions and multiple dials for astronomical observations; Used them to measure planetary motions with high accuracy.
- Raja Jai Singh II 1688–1743 CE
Late Mughal astronomer; built five large observatories in Delhi, Jaipur, Ujjair, Mathura, Varanasi; Measured solar time to + or – 2 seconds; produced Zij-i-Mohammed Shahi; engaged with European Astronomy but did not adopt heliocentrism or Newtonian Physics.
