(February 17, 1201 – June 25, 1274)
Astute, versatile and improvising, this Persian genius was a jack-of-all-trade and master-of-all. His works ramified arts and sciences. Tusi is hailed as the first person who demonstrated that Trigonometry is independent of Astronomy. His Treatise on the Quadrilateral unveiled Spherical Trigonometry in a manner neither seen nor contemplated before. He developed his famous Tusi-Couple, which is a geometrical contrivance that effectively replaced the cumbersome Ptolemy-Equant. His works on planetary motions and accurate calculations of equinoxes were appreciated by Copernicus, who used them as basis to explore the then unknown realms of astrophysics. His bioresearches showcased some of the earliest forages into genetics and taxonomy. He classified living organisms into plants, animals and humans. As an avid reader of Avicenna’s works, Tusi was inspired to follow in his footsteps. From mathematics to medicine, and chemistry to physics, his tireless researches ushered-in some of the knowhow which buttressed Renaissance and the centuries of discoveries that followed it. For an example, this statement: “A body of matter cannot disappear completely. It only changes its form, appearance, condition, composition, color and other properties and turns into a different complex or elementary matter”, which is attributed to Tusi, precedes the similar view of today’s Law of Conservation of Mass. Both the minor planet 10269 Tusi and the lunar crater Nasireddin are named after him.