Thābit ibn Qurra.
(836 in
Harran,
Mesopotamia –
February 18,
901 in
Baghdad) was an
Arab astronomer,
mathematician and
physician who was known as
Thebit in
Latin.
Biography
Thabit was born in
Harran (known as Carrhae in
antiquity) in
Mesopotamia (in modern day
Turkey). At the invitation of
Muhammad bin Musa bin Shakir, one of the
Banu Musa brothers, Thabit went to study in
Baghdad at the
House of Wisdom. He belonged to the sect of the
Sabians of Harran, a sect of
Hermeticists, often confused with the
Mandaeans. As star-worshippers, Sabians showed a great interest in
astronomy,
astrology,
magic, and
mathematics. This sect lived in the vicinity of the main center of the Caliphate until 1258, when the
Mongols destroyed their last shrine. During
Muslim rule, they were a protected minority, and around the time of
al-Mutawakkil's reign their town became a center for philosophical, esoteric, and medical learning. They may have been joined by the descendants of pagan Greek scholars who, not tolerated in the Byzantine Empire, settled in lands that became part of the
Abbasid caliphate. After 750 AD, some Muslim rulers and scholars became interested in Greek culture and
science, collecting and having translated many ancient Greek works in the fields of philosophy and mathematics. Although they later became Arabic speakers, in pre-Islamic times, it was common for Sabians to speak [Greek language].
Thabit and his pupils lived in the midst of the most intellectually vibrant, and probably the largest, city of the time, Baghdad. He occupied himself with mathematics, astronomy, astrology, magic,
mechanics,
medicine, and
philosophy. His native language was
Syriac, which was the eastern
Aramaic dialect from
Edessa, and he knew Greek well too. He translated from Greek
Apollonius,
Archimedes,
Euclid and
Ptolemy. Thabit had revised the translation of
Euclid's
Elements of
Hunayn ibn Ishaq. He also rewrote Hunayn's translation of Ptolemy's
Almagest and translated Ptolemy's
Geography. Thabit's translation of a work by Archimedes which gave a construction of a regular
heptagon was discovered in the 20th century, the original having been lost.
Later in his life, Thabit's patron was the Abbasid Caliph
al-Mu'tadid (reigned 892–902). Thabit became the Caliph's personal friend and courtier.
Thabit died in Baghdad. After him the greatest Sabean name was Abu Abdallah Mohammad ibn Jabir
Al-Battani. Thabit and his grandson
Ibrahim ibn Sinan ibn Thabit studied the curves needed for making
sundials. Thabit's son
Sinan ibn Thabit was a distinguished physician who was responsible for supervising all the public hospitals of Baghdad.He was a member of the Sabian sect.
Works
Only a few of Thabit's works are preserved in their original form.
The midevil
astronomical theory of the
trepidation of the
equinoxes is often attributed to Thabit. But it had already been described by
Theon of Alexandria in his comments of the
Handy Tables of
Ptolemaeus. According to
Copernicus Thabit determined the length of the
sidereal year as 365 days, 6 hours, 9 minutes and 12 seconds (an error of 2 seconds). Copernicus based his claim on the Latin text attributed to Thabit. Thabit published his observations of the
Sun.
In
mathematics, Thabit discovered an equation for determining the
amicable numbers. He also wrote on the
theory of numbers, and extended their use to describe the ratios between geometrical quantities, a step which the Greeks never took. Another important contribution Thabit made to
geometry was his generalization of the
Pythagorean theorem, which he extended from
special right triangles to all
triangles in general, along with a general
proof.
In
physics, Thabit rejected the
Peripatetic and
Aristotelian notions of a "natural place" for each
element. He instead proposed a theory of motion in which both the upward and downward motions are caused by
weight, and that the order of the universe is a result of two competing
attractions (
jadhb): one of these being "between the
sublunar and
celestial elements", and the other being "between all parts of each element separately".
See also
