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The Earth and Moon are much closer to being a binary planet; the center of mass around which they both rotate is still inside the Earth, but is about 4,624 km (2,873 miles) or 72.6% of the Earth's radius away from the centre of the Earth (thus closer to the surface than the center).
The Ptolemaic Kingdom (/ ˌ t ɒ l ɪ ˈ m eɪ. ɪ k /; Koinē Greek: Πτολεμαϊκὴ βασιλεία, Ptolemaïkḕ basileía) [6] or Ptolemaic Empire [7] was an Ancient Greek polity based in Egypt during the Hellenistic period. [8]
An edition in Latin of the Almagestum in 1515. The Almagest (/ ˈ æ l m ə dʒ ɛ s t / AL-mə-jest) is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c. AD 100 – c. 170) in Koine Greek. [1]
Bounded elongation is the angular distance of celestial bodies from the center of the universe. Ptolemy's model of the cosmos and his studies landed him an important place in history in the development of modern-day science. In the Ptolemaic system, the Earth was at the center of the universe with the Moon, the Sun, and five planets circling it.
The principal change was to space leap years differently so as to make the average calendar year 365.2425 days long, more closely approximating the 365.2422-day 'tropical' or 'solar' year that is determined by the Earth's revolution around the Sun. The reform advanced the date by 10 days: Thursday 4 October 1582 was followed by Friday 15 ...
The Ptolemaic system of celestial motion as depicted in the Harmonia Macrocosmica (1661). Science in classical antiquity encompasses inquiries into the workings of the world or universe aimed at both practical goals (e.g., establishing a reliable calendar or determining how to cure a variety of illnesses) as well as more abstract investigations belonging to natural philosophy.
Ptolemy publishes his star catalogue, listing 48 constellations and endorses the geocentric (Earth-centered) view of the universe. His views go unquestioned for nearly 1500 years in Europe and are passed down to Arabic and medieval European astronomers in his book the Almagest. He also proposed astronomical calculation of the sidereal ...
Ptolemy I and other early rulers of the dynasty were not married to their relatives, the childless marriage of siblings Ptolemy II and Arsinoe II [22] being an exception. The first child-producing incestuous marriage in the Ptolemaic dynasty was that of Ptolemy IV and Arsinoe III , who were succeeded as co-pharaohs by their son Ptolemy V , born ...