Thābit ibn Qurra facts for kids

Thābit ibn Qurra (full name: Abū al-Ḥasan ibn Zahrūn al-Ḥarrānī al-Ṣābiʾ, Arabic: أبو الحسن ثابت بن قرة بن زهرون الحراني الصابئ, Latin: Thebit/Thebith/Tebit); born in 826 or 836 AD and died on February 19, 901 AD. He was a very smart person who lived in Baghdad during the Abbasid Caliphate.

Thābit was a mathematician, a physician (doctor), an astronomer (someone who studies space), and a translator. He made important discoveries in many areas. These included algebra, geometry, and astronomy.

In astronomy, Thābit was one of the first to improve the Ptolemaic system. This was an old model of how the universe worked. In mechanics, which is the study of how things move, he helped start the field of statics. This is about how forces act on objects that are not moving. Thābit also wrote many books on medicine and philosophy.

Biography

The al-Jazira region during the Abbasid Caliphate

Thābit was born in a city called Harran. This city was in a region known as Upper Mesopotamia. At that time, Harran was part of the Abbasid Caliphate.

Thābit belonged to a group called the Sabians of Harran. They followed an old religion that studied the stars.

When he was young, Thābit worked as a money changer in Harran. One day, he met Muḥammad ibn Mūsā. He was the oldest of three famous mathematicians called the Banū Mūsā. Thābit was very good with languages. Because of this, ibn Mūsā asked him to come to Baghdad.

In Baghdad, Thābit was trained in mathematics, astronomy, and philosophy. He joined a group of smart scholars. He also met powerful and important people in the city.

Thābit and his students lived in Baghdad, which was a very lively city. He worked for the Banū Mūsā and helped them translate Greek math books. Thābit studied mathematics, astronomy, and even magic. Later in his life, the Caliph al-Mu'tadid became his supporter. Thābit became the Caliph's personal friend and court astronomer.

Thābit died in Baghdad in 901 AD. His son, Sinan ibn Thabit, and grandson, Ibrahim ibn Sinan, also became important in medicine and science. By the end of his life, Thābit had written 150 works. Sadly, most of his writings have been lost over time. Only about a dozen of his works still exist today.

Translation Work

Pages from Thābit's Arabic translation of Apollonius' Conics

Thābit's first language was Syriac. He also spoke Medieval Greek and Arabic very well. Because he knew three languages, Thābit played a big part in the Graeco-Arabic translation movement. This was a time when many Greek books were translated into Arabic. He even started his own translation school in Baghdad.

Thābit translated works from Greek into Arabic. These included books by famous thinkers like Apollonius of Perga, Archimedes, Euclid, and Ptolemy. He also improved earlier translations of Euclid's Elements and Ptolemy's Almagest. He translated Ptolemy's Geography too.

In the 20th century, a translation by Thābit of an Archimedes work was found. This book showed how to draw a regular heptagon (a seven-sided shape). The original Greek version of this book had been lost.

Astronomy Studies

Thābit was likely an astronomer for Caliph al-Mu'tadid. He used his math skills to study Ptolemaic astronomy. This was the main way people understood the universe back then.

Thābit is known for figuring out the length of the sidereal year. This is the time it takes for the Earth to go around the Sun once, based on distant stars. He calculated it as 365 days, 6 hours, 9 minutes, and 12 seconds. This was very close to the actual time!

He also wrote a book called De Anno Solis (About the Solar Year). In this book, he recorded important facts about astronomy in his time. Thābit believed that the Sun and Moon move in a similar way to the stars. He thought the solar year should be measured by when the Sun returns to a certain star.

Mathematics Discoveries

In mathematics, Thābit found a way to figure out amicable numbers. These are pairs of numbers where the sum of the true divisors of each number equals the other number. He wrote about this in his book, Treatise on the Derivation of the Amicable Numbers in an Easy Way.

Thābit also gave a new proof for the Pythagorean theorem. This famous theorem is about the sides of a right-angled triangle. His work combined old and new ideas about this proof. Thābit thought that geometry should include ideas about motion and physics.

He also worked on chessboard problems. This was about using combinatorics to find the number of ways to win a chess game. Combinatorics is a part of math that deals with counting, arranging, and combining things.

Thābit was also very good at conic sections. These are shapes like circles, ellipses, parabolas, and hyperbolas. He could calculate the volume of a paraboloid, which is a bowl-shaped figure. This showed his deep understanding of geometry.

Physics Ideas

In physics, Thābit had new ideas about how things move. He did not agree with the old idea that each element (like earth, water, air, fire) had a "natural place." Instead, he thought that both upward and downward movements were caused by weight.

He believed the universe was ordered by two types of attractions. One was between things on Earth and things in space. The other was between parts of each element itself. Thābit was a founder of statics, which studies forces on objects that are not moving.

His book Liber Karatonis proved the law of the lever. This law explains how levers work to lift heavy objects. He combined ideas from old Greek thinkers to create this work.

Thābit also wrote Kitab fi 'l-qarastun, which was about Arabic mechanical traditions. Another important book was Kitab fi sifat alwazn. This book talked about the idea of an equal-armed balance. Thābit was one of the first to write about this idea in a clear way.

Medicine Contributions

Thābit was also a well-known physician (doctor). He wrote many books and comments on medicine. His general medical books included 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 specific books on topics like gallstones. He discussed how to treat diseases such as smallpox and measles. He even wrote about eye conditions. Thābit also studied veterinary medicine (animal health) and the anatomy of birds. He wrote comments on the works of other famous doctors like Galen.

There is a story about Thābit healing a butcher. The butcher was very sick, and everyone thought he would die. But Thābit was able to cure him.

Works

Only a few of Thābit's many works still exist today.

• On the Sector-Figure (about Menelaus' theorem)
• On the Composition of Ratios
• Kitab fi 'l-qarastun (Book of the Steelyard)
• Kitab fi sifat alwazn (Book on the Description of Weight) - A short text on equal-armed balance

Other works by Thābit include:

• Kitāb al-Mafrūdāt (Book of Data)
• Maqāla fīistikhrāj al-a‘dād al-mutahābba bi–suhūlat al-maslak ilā dhālika (Book on the Determination of Amicable Numbers)
• Kitāb fi Misāhat qat‘ almakhrūt alladhī yusammaā al-mukāfi’ (Book on the Measurement of the Conic Section Called Parabolic)
• Kitāb fī Sanat al-shams (Book on the Solar Year)
• Qawl fi’l–Sabab alladhī ju‘ilat lahu miyāh al-bahr māliha (Discourse on the Reason Why Seawater Is Salted)
• al-Dhakhira fī ilm al-tibb (A Treasury of Medicine)
• Kitāb fi ‘ilm al-‘ayn . . . (Book on the Science of the Eye…)
• Kitāb fi’l–jadarī wa’l–hasbā (Book on Smallpox and Measles)
• Masā’il su’ila ’anhā Thābit ibn Qurra al-Harrānī (Questions Posed to Thābit. . .)

Eponyms

• Thabit number
• Thebit (crater)

See also

• al-Battani, another Sabian astronomer and mathematician from that time.