Thābit ibn Qurra

Thābit ibn Qurra (full name: Abū al-Ḥasan Ṯābit ibn Qurra ibn Zahrūn al-Ḥarrānī al-Ṣābiʾ, Arabic: أبو الحسن ثابت بن قرة بن زهرون الحراني الصابئ, Latin: Thebit/Thebith/Tebit; 826 or 836 – February 19, 901) was a smart scholar who lived during the Abbasid Caliphate. He lived in Baghdad and did many important things for science and learning.

Thābit studied many subjects, like mathematics, medicine, astronomy, and translation. He helped people understand algebra, geometry and astronomy better. In astronomy, Thābit helped change old ideas about how stars and planets move.

He also wrote about medicine and philosophy, sharing his ideas with others. Thābit’s work helped other discoverers after him.

Biography

Thābit ibn Qurra was born in Harran, a city in Upper Mesopotamia, during the time of the Abbasid Caliphate. He belonged to the Sabians of Harran, a group with old beliefs. As a young person, Thābit worked as a money changer until he met Muḥammad ibn Mūsā, one of the famous Banū Mūsā mathematicians. Thābit was very good with languages, so ibn Mūsā brought him to Baghdad to learn mathematics, astronomy, and philosophy.

In Baghdad, Thābit joined a group of scholars and helped translate important Greek math books. He later became a friend and advisor to the Abbasid Caliph al-Mu'tadid, working as his personal astronomer. Thābit wrote many works on science and medicine, though only a few remain today. His son and grandson also helped in these areas.

Translation

Thābit ibn Qurra spoke three languages: Syriac, Medieval Greek, and Arabic. Because he could read and speak these languages, he helped translate ancient Greek books into Arabic during a time called the Graeco-Arabic translation movement. He even helped start a school for translation in Baghdad.

He translated many important works from Greek into Arabic. These included books by Apollonius of Perga, Archimedes, Euclid, and Ptolemy. He improved the translation of Euclid’s book called the Elements and also worked on Ptolemy’s books called the Almagest and Geography. One of his translations of Archimedes’ work on creating a regular heptagon was found much later, even though the original Greek book had been lost.

Astronomy

Thābit was an astronomer who worked for the Caliph al-Mu'tadid. He used math to study Ptolemaic astronomy and looked at how the Sun and Moon move. Thābit also explored the idea of trepidation of the equinoxes, which is about changes in when the seasons happen over many years. According to Copernicus, Thābit discovered the length of the sidereal year, the time it takes Earth to go around the Sun and face the same stars.

Thābit wrote a book called De Anno Solis. In it, he shared his ideas about how stars, the Sun, and the Moon move. He thought the way stars move might also work for the Sun and Moon, and he suggested new ways to figure out the solar year by watching the Sun's place among the stars.

Mathematics

See also: Thabit number

In mathematics, Thābit discovered special numbers called amicable numbers. He found a formula to find them and wrote a book about his ideas. Thābit also worked on geometry and made a new proof for the Pythagorean theorem. This theorem shows the relationship between the sides of a right triangle. He thought geometry should also include ideas about motion.

Thābit's work helped him solve difficult problems, like arranging pieces in games such as chess. He also studied shapes like parabolas and used ideas from Euclid and Archimedes to learn more about their properties.

Physics

Thābit ibn Qurra studied how things move and stay still. He did not believe that each kind of matter had a special place to go. Instead, he thought that both upward and downward motion happened because of weight.

Thābit wrote important books about simple machines and balances. One of his works showed how a seesaw works, proving that weights balance based on their distance from the center. He was one of the first to organize ideas about how things balance perfectly.

Medicine

Thābit ibn Qurra was a well-known doctor. He wrote many books about medicine and commented on the work of other doctors. Some of his important books include al-Dhakhira fī ilm al-tibb ("A Treasury of Medicine") and Kitāb al-Rawda fi l–tibb ("Book of the Garden of Medicine"). He also wrote about health problems like gallstones and eye diseases. He even talked about animal health and the bodies of birds. Thābit also wrote about the ideas of other famous doctors like Galen.

One story says that Thābit helped a butcher who was thought to be very sick, and he was able to heal him.

Works

Thābit ibn Qurra wrote many important books on different subjects. Some of his surviving works include On the Sector-Figure, which talks about Menelaus' theorem, and Kitab fi 'l-qarastun (Book of the Steelyard). He also wrote about topics like measuring shapes, the solar year, and why seawater is salty.

He created books on medicine, including one called al-Dhakhira fī ilm al-tibb (A Treasury of Medicine). Thābit’s works show his deep knowledge of many areas, from math to health.

Eponyms

Thābit ibn Qurra has two things named after him. The first is called a Thabit number. This is a special kind of number used in mathematics. The second is a crater on the Moon named Thebit (crater). It is a dark spot that scientists study.