Muslim Scientists went to Astronomic Lengths for Science
From Hubble to Copernicus to Galileo, astronomers have been observing the cosmos from all over the world since the 4th Century. Everyone’s heard of Ptolemy and Hipparchus, right? The Greeks invented astronomy, right? Well, sort of.
It’s no secret that the Greeks made numerous discoveries in the astronomical world. They contributed many theories about the solar system, discovering facts about eclipses, and using geometry to make astronomical findings. But what isn’t too familiar is the astronomical pioneering that played out in the Islamic world by Muslim scientists during the same time period. There are still many significant uses of Arabic in astronomy: the name of a large number of stars in the sky, such as Aldebaran, Altair and Deneb, and astronomical terms such as alidade (a device for determining directions or measuring angles), azimuth (the direction of a celestial object from an observer, expressed as the angular distance from the north or south point of the horizon), and nadir (the local vertical direction pointing in the direction of the force of gravity at that location), are Arabic names, and are still used today. In addition, a large amount of literature from Islamic astronomy remains to this day: around 10,000 manuscripts, not including the numerous times muslim astronomers corrected previous works of other astronomers. Astronomers like Al-Sufi, Ibn al-Haytham, and Al-Zarqali contributed greatly to the advancement of their field.
The scientific observation of the skies in the muslim world began soon after the expansion of Islam, which happened around the 8th century. The sudden research into astronomy was accelerated by the need to fulfill the specific requirements of their religion, Islam. These requirements include the ability to correctly determine the time and direction of Mecca for prayer, the time of sunrise and sunset (which was needed for fasting during the celebration of Ramadan), and for knowing the position of the moon to mark the start of a new month. All of these necessities led to the advancement of scientific instruments and the improvement of the methods for making observations in the Islamic world.
Observatories owe their origin to astronomers of the Islamic world, and were beginning to be built around the 8th century all over the Medieval Islamic world, from Damascus to Baghdad. The first one constructed was the Shammasiyah observatory in Baghdad around 828 CE. In these observatories, meridian (lines of longitude) degrees were measured, solar parameters were established, and detailed observations of the cosmos, specifically the Sun, the Moon, and planets were recorded. These observatories helped Arabic scientists advance in the study of astronomy. Some of the most famous observatories in the astronomical worlds were made in Islamic countries.
Arab astronomers were also the ones to perfect astronomical instruments such as the astrolabe and the sundial. The astrolabe is an ancient tool used in solving problems that involve time and the position of the Sun and stars. The first universal astrolabe was invented by the Muslim scientist Abu Ishaq Ibrahim al-Zarqali. Unlike previous astrolabes, his astrolabe could be used at any location around the world, instead of only at a specific latitude, which gave many new uses to the astrolabe. In addition, the earliest sundials known were called shadow clocks from ancient Egyptian and Babylonian astronomy, which influenced the use of sundials all over the world. There were countless other tools also created and perfected in the Islamic world, such as sextants (a tool used for measuring the angular distances between objects and especially for taking altitudes in navigation) and almanacs (an annual calendar containing important dates and statistical information such as astronomical data).
Another aspect of science that we always use but don’t necessarily know the origins of is the idea that you need to prove your work. Muslim scientists were the first who supported their theories with evidence, rather than just believing based on speculations. The Greeks believed that scientific fact can be discovered through reason or attributed to the actions of the gods, but the Muslim scientist Ibn al-Haytham knew better. He was the first scientist in history to insist that everything be proven through a given method for discovering new information, thus creating the scientific method. Without this idea of proving scientific your theories before they are true, we may still be living in a time when speculation, superstition, and unproven myths are the basis of science.
Islamic countries were home to some of the best astronomers of their time. Habash al-Hasib was a Persian astronomer who presented us the first instance of a determination of time by the sun, which was a method which was generally adopted by Muslim astronomers. He also estimated various statistics about celestial bodies such as the Moon, the Sun, and the Earth, by making observations out of an observatory in Baghdad, and compiling them into one of his works titled The Book of Bodies and Distances. Abd al-Rahman al-Sufi, one of the most famous astronomers in the muslim world, was an Iranian scientist who contributed to the knowledge on galaxies. He was the first to discover the Andromeda Galaxy from Earth. He observed that the ecliptic plane is at an incline with the celestial equator and he, more accurately than previous astronomers, calculated the length of the solar year (the time that the Sun takes to return to the same position in the cycle of seasons) as seen from Earth. He also observed and described the stars, their positions, their magnitudes, and their color. Al-Zarqali was a Muslim Spanish astronomer, and known as being one of the bests of his time. In his work on the solar year, he was the first to demonstrate the motion of the solar apogee, the point in which it is closest to the Earth, in relation to the fixed background of the stars. In addition, he put together an almanac that provided the positions of the celestial bodies. This work provided the true daily positions of the sun for four Julian, a time interval of exactly 365.25 Earth days, used in astronomy years from 1088 CE to 1092 CE, the true positions of the five planets every 5 or 10 days over a period of 8 years for Venus, 79 years for Mars, and so forth. He also corrected Ptolemy’s estimate of the length of the Mediterranean sea from 62 degrees to the actual value of 42 degrees. In addition, the crater Arzachel on the Moon is named after him. Just to name a few.
Many other Islamic astronomers have had an impact on what astronomy is today. Ali ibn Ridwan, an egyptian astronomer, is known for creating the most detailed description of the supernova, SN 1006, the brightest stellar event in recorded history, which he observed in the year 1006 CE. A now-Tajikistani astronomer Al-Khujandi is known to have constructed the first huge mural sextant (an instrument used for measuring the angular distances between objects and especially for taking altitudes in navigation) in 994 CE, which was intended to determine the Earth's axial tilt to high precision. He also discovered that the axial tilt is not constant but is in fact decreasing by calculating the axial tilt and comparing it to previous readings.
Not to mention, so many astronomers in Islam’s works were how Europeans got their ideas for their work. Islamic astronomers even made countless corrections to the works of European astronomers. Al-Battani wrote many books about astronomy and mathematics, and his most famous book, ’KIitabal-Zij’ was entirely about improving upon the work of Ptolemy. He improved upon Ptolemy’s work on mapping planetary motion and solar apogees. Ibn-Al-Haytham also corrected a lot of Ptolemy’s work, specifically on planetary motion and also wrote about the laws regarding the movement of bodies and the attraction between two bodies, which were later known as Newton’s Three Laws of Motion and Gravity. Al-Haytham’s work also included ideas about lenses and parabolic mirrors, but he never never went as far as making a telescope, which was created by a European scientist later on.
Many people today are under the impression that the Greeks did everything for astronomy, and that is how it is commonly taught, too. And despite the many accomplishments that the Europeans did have, the Arabs had quite a few too, and, frankly, their knowledge was the basis for a lot of European’s work. The astronomical world wouldn’t be the same without the works of Islamic astronomers back then. They were innovative and essential for the advancement of astronomy, along with many other branches of science, even if they didn’t receive the credit they deserved.
