al-Birjandi | |
---|---|
Died | 1525–1526 |
Academic background | |
Influences | Naṣīr al‐Dīn al‐Ṭūsī, al-Kashi |
Academic work | |
Era | Islamic Golden Age |
Abdal Ali ibn Muhammad ibn Husayn Birjandi (Persian: عبدالعلی محمد بن حسین بیرجندی) (died 1528) was a prominent 16th-century Persian astronomer, mathematician and physicist who lived in Birjand.
Al-Birjandi was a pupil for Mansur ibn Muin al-Din al-Kashi, a member at the Samarkand Observatory, otherwise known as The Ulugh Beg Observatory.[1] In discussing the structure of the cosmos, al-Birjandi continued Ali al-Qushji's debate on the Earth's rotation.[2][3][4] In his analysis of what might occur if the Earth were moving, he develops a hypothesis similar to Galileo Galilei's notion of "circular inertia",[5] which he described in the following observational test (as a response to one of Qutb al-Din al-Shirazi's arguments):
The small or large rock will fall to the Earth along the path of a line that is perpendicular to the plane (sath) of the horizon; this is witnessed by experience (tajriba). And this perpendicular is away from the tangent point of the Earth's sphere and the plane of the perceived (hissi) horizon. This point moves with the motion of the Earth and thus there will be no difference in place of fall of the two rocks.[6]
Al-Birjandi wrote some more than 13 books and treatises, including:[7]
Birjandi contributed to many different fields besides his commentaries. His works included studies of ephemerides, instruments for astronomical observations, and cosmology. He also worked in determining the size and distance of planets that have been associated to Habib Allah.[1]
He also had works in the field of theology and made a series of almanacs in 1478/1479.