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Al-Sijzi

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Abu Sa'id al-Sijzi
A page from Al Sijzi'sgeometricaltreatise
Born945 CE
Died1020 CE
Main interests
Mathematics,Astronomy,Astrology
Model of the solar system and earth movement ( "planetarium" ) according to al-Sijzi[2]

Abu Sa'id Ahmed ibn Mohammed ibn Abd al-Jalil al-Sijzi(c. 945 - c. 1020, also known asal-Sinjariandal-Sijazi;Persian:ابوسعید سجزی;Al-Sijziis short for "Al-Sijistani") was anIranian[3]Muslim astronomer,mathematician,andastrologer.He is notable for his correspondence withal-Biruniand for proposing that theEarth rotates around its axisin the 10th century.[4][5]

He dedicated work to'Adud al-Daula,who was probably his patron, and to the prince ofBalkh.He also worked inShirazmaking astronomical observations from 969 to 970.

Mathematics[edit]

Al-Sijzi studied intersections of conic sections and circles. He replaced the old kinematicaltrisection of an angleby a purely geometric solution (intersection of a circle and an equilateral hyperbola.)

Earth's rotation[edit]

Al-Birunitells us that Al-Sijzi invented anastrolabe,called "al-zūraqī", whose design was based on the idea that the Earth rotates:[6]

I have seen the astrolabe called Zuraqi invented by Abu Sa'id Sijzi. I liked it very much and praised him a great deal, as it is based on the idea entertained by some to the effect that the motion we see is due to the Earth's movement and not to that of the sky. By my life, it is a problem difficult of solution and refutation. [...] For it is the same whether you take it that the Earth is in motion or the sky. For, in both cases, it does not affect the Astronomical Science. It is just for the physicist to see if it is possible to refute it.

Al-Biruni also referred to Al-Sijzi as a prominent astronomer who defended the theory that the earth rotates inal-Qānūn al-Masʿūdī.[4][7]

The fact that some people did believe that the earth is moving on its own axis is further confirmed by a reference from the 13th century which states:

"According to the geometers [or engineers] (muhandisīn), the earth is in constant circular motion, and what appears to be the motion of the heavens is actually due to the motion of the earth and not the stars. "[5]

References[edit]

  1. ^Helaine Selin (12 March 2008).Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures.Springer Science & Business Media.pp. 159–.ISBN978-1-4020-4559-2.
  2. ^"Modell des Sonnensystems und der Erdbewegung (" Planetarium ") nach as-Siǧzî".Museum des Institutes für Geschichte der Arabisch-Islamischen Wissenschaften. 2010.
  3. ^Kheirandish, Elaheh (1 April 2006). "The" Fluctuating Fortunes of Scholarship ": A Very Late Review Occasioned by a Fallen Book".Early Science and Medicine.11(2): 214.doi:10.1163/157338206776908882.
  4. ^abBausani, Alessandro (1973). "Cosmology and Religion in Islam".Scientia/Rivista di Scienza.108(67): 762.
  5. ^abYoung, M. J. L., ed. (2006-11-02).Religion, Learning and Science in the 'Abbasid Period.Cambridge University Press.p.413.ISBN9780521028875.
  6. ^SeyyedHossein Nasr(1993),An Introduction to Islamic Cosmological Doctrines,pp. 135–136.State University of New York Press,ISBN0-7914-1516-3.
  7. ^"ʾaḥad al-mubrazīn fī ʿilm al-hayʾa"

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