Template:Are You Sure/February 18
• ... that physician, astronomer, and mathematician Thābit ibn Qurra Thabit rejected the Peripatetic and Aristotelian notions of a "natural place" for each element, and that Thābit instead proposed a theory of motion in which both the upward and downward motions are caused by weight, with the order of the universe 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"?
• ... that mathematician Karl Weierstrass formalized the definition of the continuity of a function, proved the intermediate value theorem and the Bolzano–Weierstrass theorem, and used the latter to study the properties of continuous functions on closed bounded intervals?