186 relations: Ab Urbe Condita Libri, Abd al-Rahman al-Sufi, Al-Biruni, Alexandria, Almagest, Ancient Greece, Antiochus III the Great, Apollonius of Perga, Apparent magnitude, Apsis, Aratus, Archimedes, Arctic Circle, Aristarchus of Samos, Aristyllus, Arithmetic, Armillary sphere, Asger Aaboe, Asteroid, Astrolabe, Astronomer, Athens, Atlantic Ocean, Axial precession, Axial tilt, Āryabhaṭa's sine table, İznik, Babylon, Babylonia, Babylonian astronomical diaries, Babylonian astronomy, Bithynia, Bursa Province, Callippus, Caspian Sea, Celestial globe, Chaldea, Chord (geometry), City, Classical antiquity, Classical mechanics, Cleomedes, Clime, Coin, Conformal map, Conical surface, Copernican heliocentrism, Cylinder, Dardanelles, Declination, ..., Deferent and epicycle, Degree (angle), Dennis Rawlins, Diameter, Dicaearchus, Dioptra, Dioptre, Ecliptic, Ecliptic coordinate system, Ecumene, Ellipse, Enumerative combinatorics, Ephemeris, Equation of the center, Equator, Equatorial coordinate system, Equatorial ring, Equinox, Eratosthenes, Euclidean geometry, Euctemon, Eudoxus of Cnidus, European Space Agency, Farnese Atlas, Fixed stars, Franz Xaver Kugler, Geographer, Geographic coordinate system, Geographica, Geography (Ptolemy), Gerald J. Toomer, Globe, Gnomon, Griffith Observatory, Hebrew calendar, Hellenistic period, Hipparchus (lunar crater), Hipparcos, Indian Ocean, ΔT, Jean Baptiste Joseph Delambre, Johannes Kepler, Journal for the History of Astronomy, Kanyakumari, Karl Manitius, Kidinnu, Latitude, Lazare Carnot, List of minor planets: 3001–4000, Livy, Loeb Classical Library, Longitude, Lucio Russo, Lunar eclipse, Lunar month, Lunar theory, March equinox, Mathematician, Mean, Menelaus of Alexandria, Meridian (astronomy), Messina, Meton of Athens, Metonic cycle, Minute and second of arc, Moon, N. R. Pogson, Natural History (Pliny), Nicaea, Nicolaus Copernicus, Opposition (planets), Orbit, Orbital eccentricity, Orbital period, Otto E. Neugebauer, Pappus of Alexandria, Parallax, Pi, Plane (geometry), Planet, Pliny the Elder, Plutarch, Poetry, Precession, Proclus, Proleptic Julian calendar, Ptolemy, Ptolemy's theorem, Pythagorean theorem, Radius, Raphael, Refraction, Regulus, Rhodes, Robert Russell Newton, Roman Republic, Saros (astronomy), Scaphe, Schröder–Hipparchus number, Season, Sexagesimal, Sicily, Sidereal year, Solar eclipse, Solstice, Sphere, Spherical trigonometry, Spica, Star, Star catalogue, Stereographic projection, Strabo, Suda, Sun, Supernova, Surya Siddhanta, Synesius, The School of Athens, Theon of Alexandria, Theon of Smyrna, Theorem, Time, Timocharis, Triangulation, Trigonometric functions, Trigonometric tables, Trigonometry, Tropical year, Turkey, Tycho Brahe, Ulugh Beg, University of Arizona, University of Cambridge, University of Oregon, Vettius Valens, Volume. Expand index (136 more) » « Shrink index
Livy's History of Rome, sometimes referred to as Ab Urbe Condita, is a monumental history of ancient Rome, written in Latin, between 27 and 9 BC.
'Abd al-Rahman al-Sufi (عبدالرحمن صوفی (December 7, 903 in Rey, Iran – May 25, 986 in Shiraz, Iran) was a Persian astronomer also known as 'Abd ar-Rahman as-Sufi, 'Abd al-Rahman Abu al-Husayn, 'Abdul Rahman Sufi, or 'Abdurrahman Sufi and, historically, in the West as Azophi and Azophi Arabus. The lunar crater Azophi and the minor planet 12621 Alsufi are named after him. Al-Sufi published his famous Book of Fixed Stars in 964, describing much of his work, both in textual descriptions and pictures. Al-Biruni reports that his work on the ecliptic was carried out in Shiraz. He lived at the Buyid court in Isfahan.
Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī (Chorasmian/ابوریحان بیرونی Abū Rayḥān Bērōnī; New Persian: Abū Rayḥān Bīrūnī) (973–1050), known as Al-Biruni (البيروني) in English, was an IranianD.J. Boilot, "Al-Biruni (Beruni), Abu'l Rayhan Muhammad b. Ahmad", in Encyclopaedia of Islam (Leiden), New Ed., vol.1:1236–1238.
Alexandria (or; Arabic: الإسكندرية; Egyptian Arabic: إسكندرية; Ⲁⲗⲉⲝⲁⲛⲇⲣⲓⲁ; Ⲣⲁⲕⲟⲧⲉ) is the second-largest city in Egypt and a major economic centre, extending about along the coast of the Mediterranean Sea in the north central part of the country.
The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy. One of the most influential scientific texts of all time, its geocentric model was accepted for more than 1200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus.
Ancient Greece was a civilization belonging to a period of Greek history from the Greek Dark Ages of the 13th–9th centuries BC to the end of antiquity (AD 600).
Antiochus III the Great (Greek: Ἀντίoχoς Μέγας; c. 241187 BC, ruled 222–187 BC) was a Hellenistic Greek king and the 6th ruler of the Seleucid Empire.
Apollonius of Perga (Ἀπολλώνιος ὁ Περγαῖος; Apollonius Pergaeus; late 3rdearly 2nd centuries BC) was a Greek geometer and astronomer known for his theories on the topic of conic sections.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
Aratus (Ἄρατος ὁ Σολεύς; ca. 315 BC/310 BC240) was a Greek didactic poet.
Archimedes of Syracuse (Ἀρχιμήδης) was a Greek mathematician, physicist, engineer, inventor, and astronomer.
The Arctic Circle is the most northerly of the five major circles of latitude as shown on maps of Earth.
Aristarchus of Samos (Ἀρίσταρχος ὁ Σάμιος, Aristarkhos ho Samios; c. 310 – c. 230 BC) was an ancient Greek astronomer and mathematician who presented the first known model that placed the Sun at the center of the known universe with the Earth revolving around it (see Solar system).
Aristyllus (Ἀρίστυλλος; fl. c. 261 BC) was a Greek astronomer, presumably of the school of Timocharis (c. 300 BC).
Arithmetic (from the Greek ἀριθμός arithmos, "number") is a branch of mathematics that consists of the study of numbers, especially the properties of the traditional operations on them—addition, subtraction, multiplication and division.
An armillary sphere (variations are known as spherical astrolabe, armilla, or armil) is a model of objects in the sky (on the celestial sphere), consisting of a spherical framework of rings, centred on Earth or the Sun, that represent lines of celestial longitude and latitude and other astronomically important features, such as the ecliptic.
Asger Hartvig Aaboe (April 26, 1922 – January 19, 2007) was a historian of the exact sciences and mathematician who is known for his contributions to the history of ancient Babylonian astronomy.
Asteroids are minor planets, especially those of the inner Solar System.
An astrolabe (ἀστρολάβος astrolabos; ٱلأَسْطُرلاب al-Asturlāb; اَختِرِیاب Akhteriab) is an elaborate inclinometer, historically used by astronomers and navigators to measure the inclined position in the sky of a celestial body, day or night.
An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside the scope of Earth.
Athens (Αθήνα, Athína; Ἀθῆναι, Athênai) is the capital and largest city of Greece.
The Atlantic Ocean is the second largest of the world's oceans with a total area of about.
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis.
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, or, equivalently, the angle between its equatorial plane and orbital plane.
Āryabhaṭa's sine table is a set of twenty-four numbers given in the astronomical treatise Āryabhaṭīya composed by the fifth century Indian mathematician and astronomer Āryabhaṭa (476–550 CE), for the computation of the half-chords of certain set of arcs of a circle.
İznik is a town and an administrative district in the Province of Bursa, Turkey.
Babylon (KA2.DIĜIR.RAKI Bābili(m); Aramaic: בבל, Babel; بَابِل, Bābil; בָּבֶל, Bavel; ܒܒܠ, Bāwēl) was a key kingdom in ancient Mesopotamia from the 18th to 6th centuries BC.
Babylonia was an ancient Akkadian-speaking state and cultural area based in central-southern Mesopotamia (present-day Iraq).
The Babylonian astronomical diaries are a collection of Babylonian cuneiform texts which contain systematic records of astronomical observations and political events, as well as predictions based on astronomical observations.
The history of astronomy in Mesopotamia, and the world, begins with the Sumerians who developed the earliest writing system—known as cuneiform—around 3500–3200 BC.
Bithynia (Koine Greek: Βιθυνία, Bithynía) was an ancient region, kingdom and Roman province in the northwest of Asia Minor, adjoining the Propontis, the Thracian Bosporus and the Euxine Sea.
Bursa Province (Bursa ili) is a province in Turkey, along the Sea of Marmara coast in northwestern Anatolia. Its adjacent provinces are Balıkesir to the west, Kütahya to the south, Bilecik and Sakarya to the east, Kocaeli to the northeast and Yalova to the north. The province has an area of 11,043 km2 and a population of 2,842,547 (2015). Its population was 2,125,140 according to the 2000 census. In 1990 it had a population of 1,603,137. The traffic code is 16. The vast majority of the Bursa Province districts (and the city of Bursa) are located within the Marmara Region; but the districts of Büyükorhan, Harmancık, Keles and Orhaneli are located within the Aegean Region. The city of Bursa was the capital of the Ottoman State between 1326 and 1365, until the Ottoman conquest of Edirne (Adrianople) which became the new Ottoman capital between 1365 and 1453 (the year when Istanbul (Constantinople) became the final Ottoman capital until 1923.).
Callippus (Κάλλιππος; c. 370 BC – c. 300 BC) was a Greek astronomer and mathematician.
The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea.
Celestial globes show the apparent positions of the stars in the sky.
Chaldea or Chaldaea was a Semitic-speaking nation that existed between the late 10th or early 9th and mid-6th centuries BC, after which it and its people were absorbed and assimilated into Babylonia.
A chord of a circle is a straight line segment whose endpoints both lie on the circle.
A city is a large human settlement.
Classical antiquity (also the classical era, classical period or classical age) is the period of cultural history between the 8th century BC and the 5th or 6th century AD centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world.
Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars and galaxies.
Cleomedes (Κλεομήδης) was a Greek astronomer who is known chiefly for his book On the Circular Motions of the Celestial Bodies (Κυκλικὴ θεωρία μετεώρων).
The climes (singular clime; also clima, plural climata, from Greek κλίμα klima, plural κλίματα klimata, meaning "inclination" or "slope") in classical Greco-Roman geography and astronomy were the divisions of the inhabited portion of the spherical Earth by geographic latitude.
A coin is a small, flat, (usually) round piece of metal or plastic used primarily as a medium of exchange or legal tender.
In mathematics, a conformal map is a function that preserves angles locally.
In geometry, a (general) conical surface is the unbounded surface formed by the union of all the straight lines that pass through a fixed point — the apex or vertex — and any point of some fixed space curve — the directrix — that does not contain the apex.
Copernican heliocentrism is the name given to the astronomical model developed by Nicolaus Copernicus and published in 1543.
A cylinder (from Greek κύλινδρος – kulindros, "roller, tumbler"), has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes.
The Dardanelles (Çanakkale Boğazı, translit), also known from Classical Antiquity as the Hellespont (Ἑλλήσποντος, Hellespontos, literally "Sea of Helle"), is a narrow, natural strait and internationally-significant waterway in northwestern Turkey that forms part of the continental boundary between Europe and Asia, and separates Asian Turkey from European Turkey.
In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle.
In the Hipparchian and Ptolemaic systems of astronomy, the epicycle (from ἐπίκυκλος, literally upon the circle, meaning circle moving on another circle) was a geometric model used to explain the variations in speed and direction of the apparent motion of the Moon, Sun, and planets.
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane angle, defined so that a full rotation is 360 degrees.
Dennis Rawlins (born 1937) is an American astronomer and historian who has acquired the reputation of skeptic primarily with respect to historical claims connected to astronomical considerations.
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle.
Dicaearchus of Messana (Δικαίαρχος Dikaiarkhos), also written Dicearchus or Dicearch, was a Greek philosopher, cartographer, geographer, mathematician and author.
A dioptra (sometimes also named dioptre or diopter from διόπτρα) is a classical astronomical and surveying instrument, dating from the 3rd century BCE.
A dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions and orbits of Solar System objects.
The ecumene (US) or oecumene (UK; οἰκουμένη, oikouménē, "inhabited") was an ancient Greek term for the known world, the inhabited world, or the habitable world.
In mathematics, an ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.
Enumerative combinatorics is an area of combinatorics that deals with the number of ways that certain patterns can be formed.
In astronomy and celestial navigation, an ephemeris (plural: ephemerides) gives the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times.
In two-body, Keplerian orbital mechanics, the equation of the center is the angular difference between the actual position of a body in its elliptical orbit and the position it would occupy if its motion were uniform, in a circular orbit of the same period.
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel).
The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects.
An equatorial ring was an astronomical instrument used in the Hellenistic world to determine the exact moment of the spring and autumn equinoxes.
An equinox is commonly regarded as the moment the plane (extended indefinitely in all directions) of Earth's equator passes through the center of the Sun, which occurs twice each year, around 20 March and 22-23 September.
Eratosthenes of Cyrene (Ἐρατοσθένης ὁ Κυρηναῖος,; –) was a Greek mathematician, geographer, poet, astronomer, and music theorist.
Euclidean geometry is a mathematical system attributed to Alexandrian Greek mathematician Euclid, which he described in his textbook on geometry: the Elements.
Euctemon (Εὐκτήμων, gen. Εὐκτήμωνος; fl. 432 BC) was an Athenian astronomer.
Eudoxus of Cnidus (Εὔδοξος ὁ Κνίδιος, Eúdoxos ho Knídios) was an ancient Greek astronomer, mathematician, scholar, and student of Archytas and Plato.
The European Space Agency (ESA; Agence spatiale européenne, ASE; Europäische Weltraumorganisation) is an intergovernmental organisation of 22 member states dedicated to the exploration of space.
The Farnese Atlas is a 2nd-century Roman marble copy of a Hellenistic sculpture of Atlas kneeling with the celestial spheres, not a globe, weighing heavily on his shoulders.
The fixed stars (stellae fixae) comprise the background of astronomical objects that appear to not move relative to each other in the night sky compared to the foreground of Solar System objects that do.
Franz Xaver Kugler (27 November 1862 – 25 January 1929) was a German chemist, mathematician, Assyriologist, and Jesuit priest.
A geographer is a scholar whose area of study is geography, the study of Earth's natural environment and human society.
A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols.
The Geographica (Ancient Greek: Γεωγραφικά Geōgraphiká), or Geography, is an encyclopedia of geographical knowledge, consisting of 17 'books', written in Greek by Strabo, an educated citizen of the Roman Empire of Greek descent.
The Geography (Γεωγραφικὴ Ὑφήγησις, Geōgraphikḕ Hyphḗgēsis, "Geographical Guidance"), also known by its Latin names as the Geographia and the Cosmographia, is a gazetteer, an atlas, and a treatise on cartography, compiling the geographical knowledge of the 2nd-century Roman Empire.
Gerald James Toomer (born 23 November 1934) is a historian of astronomy and mathematics who has written numerous books and papers on ancient Greek and medieval Islamic astronomy.
A globe is a spherical model of Earth, of some other celestial body, or of the celestial sphere.
A gnomon (from Greek γνώμων, gnōmōn, literally: "one that knows or examines") is the part of a sundial that casts a shadow.
Griffith Observatory is a facility in Los Angeles, California, sitting on the south-facing slope of Mount Hollywood in Los Angeles' Griffith Park.
The Hebrew or Jewish calendar (Ha-Luah ha-Ivri) is a lunisolar calendar used today predominantly for Jewish religious observances.
The Hellenistic period covers the period of Mediterranean history between the death of Alexander the Great in 323 BC and the emergence of the Roman Empire as signified by the Battle of Actium in 31 BC and the subsequent conquest of Ptolemaic Egypt the following year.
Hipparchus is the degraded remnant of a lunar impact crater.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993.
The Indian Ocean is the third largest of the world's oceanic divisions, covering (approximately 20% of the water on the Earth's surface).
In precise timekeeping, ΔT (Delta T, delta-T, deltaT, or DT) is the time difference obtained by subtracting Universal Time (UT) from Terrestrial Time (TT):.
Jean Baptiste Joseph, chevalier Delambre (19 September 1749 – 19 August 1822) was a French mathematician and astronomer.
Johannes Kepler (December 27, 1571 – November 15, 1630) was a German mathematician, astronomer, and astrologer.
Journal for the History of Astronomy (JHA) is a peer-reviewed academic journal that publishes papers in the History of Astronomy from earliest times to the present, and in history in the service of astronomy.
Kanyakumari is a City in Kanyakumari district in the state of Tamil Nadu, India.
Karl Manitius (23 July 1899 – 26 December 1979) was a German historian.
Kidinnu (also Kidunnu) (fl. 4th century BC? possibly died 14 August 330 BC) was a Chaldean astronomer and mathematician.
In geography, latitude is a geographic coordinate that specifies the north–south position of a point on the Earth's surface.
Lazare Nicolas Marguerite, Count Carnot (13 May 1753 – 2 August 1823) was a French mathematician, physicist and politician.
#d6d6d6 | 3089 Oujianquan || || December 3, 1981 || Nanking || Purple Mountain Obs.
Titus Livius Patavinus (64 or 59 BCAD 12 or 17) – often rendered as Titus Livy, or simply Livy, in English language sources – was a Roman historian.
The Loeb Classical Library (LCL; named after James Loeb) is a series of books, today published by Harvard University Press, which presents important works of ancient Greek and Latin literature in a way designed to make the text accessible to the broadest possible audience, by presenting the original Greek or Latin text on each left-hand page, and a fairly literal translation on the facing page.
Longitude, is a geographic coordinate that specifies the east-west position of a point on the Earth's surface.
Lucio Russo (born 22 November 1944) is an Italian physicist, mathematician and historian of science.
A lunar eclipse occurs when the Moon passes directly behind Earth and into its shadow.
In lunar calendars, a lunar month is the time between two successive syzygies (new moons or full moons).
Lunar theory attempts to account for the motions of the Moon.
The March equinox or Northward equinox is the equinox on the Earth when the subsolar point appears to leave the southern hemisphere and cross the celestial equator, heading northward as seen from Earth.
A mathematician is someone who uses an extensive knowledge of mathematics in his or her work, typically to solve mathematical problems.
In mathematics, mean has several different definitions depending on the context.
Menelaus of Alexandria (Μενέλαος ὁ Ἀλεξανδρεύς, Menelaos ho Alexandreus; c. 70 – 140 CE) was a Greek mathematician and astronomer, the first to recognize geodesics on a curved surface as natural analogs of straight lines.
In astronomy, the meridian is the great circle passing through the celestial poles, the zenith, and the nadir of an observer's location.
Messina (Sicilian: Missina; Messana, Μεσσήνη) is the capital of the Italian Metropolitan City of Messina.
Meton of Athens (Μέτων ὁ Ἀθηναῖος; gen.: Μέτωνος) was a Greek mathematician, astronomer, geometer, and engineer who lived in Athens in the 5th century BC.
For astronomy and calendar studies, the Metonic cycle or Enneadecaeteris (from ἐννεακαιδεκαετηρίς, "nineteen years") is a period of very close to 19 years that is nearly a common multiple of the solar year and the synodic (lunar) month.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
Norman Robert Pogson, CIE (23 March 1829 – 23 June 1891) was an English astronomer who worked in India at the Madras observatory.
The Natural History (Naturalis Historia) is a book about the whole of the natural world in Latin by Pliny the Elder, a Roman author and naval commander who died in 79 AD.
Nicaea or Nicea (Νίκαια, Níkaia; İznik) was an ancient city in northwestern Anatolia, and is primarily known as the site of the First and Second Councils of Nicaea (the first and seventh Ecumenical councils in the early history of the Christian Church), the Nicene Creed (which comes from the First Council), and as the capital city of the Empire of Nicaea following the Fourth Crusade in 1204, until the recapture of Constantinople by the Byzantines in 1261.
Nicolaus Copernicus (Mikołaj Kopernik; Nikolaus Kopernikus; Niklas Koppernigk; 19 February 1473 – 24 May 1543) was a Renaissance-era mathematician and astronomer who formulated a model of the universe that placed the Sun rather than the Earth at the center of the universe, likely independently of Aristarchus of Samos, who had formulated such a model some eighteen centuries earlier.
In positional astronomy, two astronomical objects are said to be in opposition when they are on opposite sides of the celestial sphere, as observed from a given body (usually Earth).
In physics, an orbit is the gravitationally curved trajectory of an object, such as the trajectory of a planet around a star or a natural satellite around a planet.
The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle.
The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.
Otto Eduard Neugebauer (May 26, 1899 – February 19, 1990) was an Austrian American mathematician and historian of science who became known for his research on the history of astronomy and the other exact sciences in antiquity and into the Middle Ages.
Pappus of Alexandria (Πάππος ὁ Ἀλεξανδρεύς; c. 290 – c. 350 AD) was one of the last great Greek mathematicians of Antiquity, known for his Synagoge (Συναγωγή) or Collection (c. 340), and for Pappus's hexagon theorem in projective geometry.
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
The number is a mathematical constant.
In mathematics, a plane is a flat, two-dimensional surface that extends infinitely far.
A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.
Pliny the Elder (born Gaius Plinius Secundus, AD 23–79) was a Roman author, naturalist and natural philosopher, a naval and army commander of the early Roman Empire, and friend of emperor Vespasian.
Plutarch (Πλούταρχος, Ploútarkhos,; c. CE 46 – CE 120), later named, upon becoming a Roman citizen, Lucius Mestrius Plutarchus, (Λούκιος Μέστριος Πλούταρχος) was a Greek biographer and essayist, known primarily for his Parallel Lives and Moralia.
Poetry (the term derives from a variant of the Greek term, poiesis, "making") is a form of literature that uses aesthetic and rhythmic qualities of language—such as phonaesthetics, sound symbolism, and metre—to evoke meanings in addition to, or in place of, the prosaic ostensible meaning.
Precession is a change in the orientation of the rotational axis of a rotating body.
Proclus Lycaeus (8 February 412 – 17 April 485 AD), called the Successor (Greek Πρόκλος ὁ Διάδοχος, Próklos ho Diádokhos), was a Greek Neoplatonist philosopher, one of the last major classical philosophers (see Damascius).
The proleptic Julian calendar is produced by extending the Julian calendar backwards to dates preceding AD 4 when the quadrennial leap year stabilized.
Claudius Ptolemy (Κλαύδιος Πτολεμαῖος, Klaúdios Ptolemaîos; Claudius Ptolemaeus) was a Greco-Roman mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology.
In Euclidean geometry, Ptolemy's theorem is a relation between the four sides and two diagonals of a cyclic quadrilateral (a quadrilateral whose vertices lie on a common circle).
In mathematics, the Pythagorean theorem, also known as Pythagoras' theorem, is a fundamental relation in Euclidean geometry among the three sides of a right triangle.
In classical geometry, a radius of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length.
Raffaello Sanzio da Urbino (March 28 or April 6, 1483April 6, 1520), known as Raphael, was an Italian painter and architect of the High Renaissance.
Refraction is the change in direction of wave propagation due to a change in its transmission medium.
Regulus, also designated Alpha Leonis (α Leonis, abbreviated Alpha Leo, α Leo), is the brightest star in the constellation of Leo and one of the brightest stars in the night sky, lying approximately 79 light years from the Sun.
Rhodes (Ρόδος, Ródos) is the largest of the Dodecanese islands of Greece in terms of land area and also the island group's historical capital.
Robert Russell Newton, also R. R. Newton (July 7, 1918 – June 2, 1991) was an American physicist, astronomer, and historian of science.
The Roman Republic (Res publica Romana) was the era of classical Roman civilization beginning with the overthrow of the Roman Kingdom, traditionally dated to 509 BC, and ending in 27 BC with the establishment of the Roman Empire.
The Saros is a period of approximately 223 synodic months (approximately 6585.3211 days, or 18 years, 11 days, 8 hours), that can be used to predict eclipses of the Sun and Moon.
The Scaphe (bowl) was a sundial said to have been invented by Aristarchus (3rd century BC).
In number theory, the Schröder–Hipparchus numbers form an integer sequence that can be used to count the number of plane trees with a given set of leaves, the number of ways of inserting parentheses into a sequence, and the number of ways of dissecting a convex polygon into smaller polygons by inserting diagonals.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight.
Sexagesimal (base 60) is a numeral system with sixty as its base.
Sicily (Sicilia; Sicìlia) is the largest island in the Mediterranean Sea.
A sidereal year (from Latin sidus "asterism, star") is the time taken by the Earth to orbit the Sun once with respect to the fixed stars.
A solar eclipse (as seen from the planet Earth) is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and when the Moon fully or partially blocks ("occults") the Sun.
A solstice is an event occurring when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere.
A sphere (from Greek σφαῖρα — sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball (viz., analogous to the circular objects in two dimensions, where a "circle" circumscribes its "disk").
Spherical trigonometry is the branch of spherical geometry that deals with the relationships between trigonometric functions of the sides and angles of the spherical polygons (especially spherical triangles) defined by a number of intersecting great circles on the sphere.
Spica, also designated Alpha Virginis (α Virginis, abbreviated Alpha Vir, α Vir), is the brightest star in the constellation of Virgo and the 16th brightest star in the night sky.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
A star catalogue (Commonwealth English) or star catalog (American English), is an astronomical catalogue that lists stars.
In geometry, the stereographic projection is a particular mapping (function) that projects a sphere onto a plane.
Strabo (Στράβων Strábōn; 64 or 63 BC AD 24) was a Greek geographer, philosopher, and historian who lived in Asia Minor during the transitional period of the Roman Republic into the Roman Empire.
The Suda or Souda (Soûda; Suidae Lexicon) is a large 10th-century Byzantine encyclopedia of the ancient Mediterranean world, formerly attributed to an author called Soudas (Σούδας) or Souidas (Σουίδας).
The Sun is the star at the center of the Solar System.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
The Surya Siddhanta is the name of a Sanskrit treatise in Indian astronomy from 6th Century BCE.
Synesius (Συνέσιος; c. 373 – c. 414), a Greek bishop of Ptolemais in the Libyan Pentapolis after 410, was born of wealthy parents who claimed descent from Spartan kings, at Balagrae (now Bayda, Libya) near Cyrene between 370 and 375.
The School of Athens (Scuola di Atene) is one of the most famous frescoes by the Italian Renaissance artist Raphael.
Theon of Alexandria (Θέων ὁ Ἀλεξανδρεύς; 335 – c. 405) was a Greek scholar and mathematician who lived in Alexandria, Egypt.
Theon of Smyrna (Θέων ὁ Σμυρναῖος Theon ho Smyrnaios, gen. Θέωνος Theonos; fl. 100 CE) was a Greek philosopher and mathematician, whose works were strongly influenced by the Pythagorean school of thought.
In mathematics, a theorem is a statement that has been proven on the basis of previously established statements, such as other theorems, and generally accepted statements, such as axioms.
Time is the indefinite continued progress of existence and events that occur in apparently irreversible succession from the past through the present to the future.
Timocharis of Alexandria (Τιμόχαρις or Τιμοχάρης, gen. Τιμοχάρους; c. 320–260 BC) was a Greek astronomer and philosopher.
In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to it from known points.
In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are functions of an angle.
In mathematics, tables of trigonometric functions are useful in a number of areas.
Trigonometry (from Greek trigōnon, "triangle" and metron, "measure") is a branch of mathematics that studies relationships involving lengths and angles of triangles.
A tropical year (also known as a solar year) is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice.
Turkey (Türkiye), officially the Republic of Turkey (Türkiye Cumhuriyeti), is a transcontinental country in Eurasia, mainly in Anatolia in Western Asia, with a smaller portion on the Balkan peninsula in Southeast Europe.
Tycho Brahe (born Tyge Ottesen Brahe;. He adopted the Latinized form "Tycho Brahe" (sometimes written Tÿcho) at around age fifteen. The name Tycho comes from Tyche (Τύχη, meaning "luck" in Greek, Roman equivalent: Fortuna), a tutelary deity of fortune and prosperity of ancient Greek city cults. He is now generally referred to as "Tycho," as was common in Scandinavia in his time, rather than by his surname "Brahe" (a spurious appellative form of his name, Tycho de Brahe, only appears much later). 14 December 154624 October 1601) was a Danish nobleman, astronomer, and writer known for his accurate and comprehensive astronomical and planetary observations.
Mīrzā Muhammad Tāraghay bin Shāhrukh (میرزا محمد طارق بن شاہ رخ, میرزا محمد تراغای بن شاہ رخ), better known as Ulugh Beg (March 22, 1394 in Sultaniyeh, Persia – October 27, 1449, Samarkand), was a Timurid ruler as well as an astronomer, mathematician and sultan.
The University of Arizona (also referred to as U of A, UA, or Arizona) is a public research university in Tucson, Arizona.
The University of Cambridge (informally Cambridge University)The corporate title of the university is The Chancellor, Masters, and Scholars of the University of Cambridge.
The University of Oregon (also referred to as UO, U of O or Oregon) is a public flagship research university in Eugene, Oregon.
Vettius Valens (February 8, 120 – c. 175) was a 2nd-century Hellenistic astrologer, a somewhat younger contemporary of Claudius Ptolemy.
Volume is the quantity of three-dimensional space enclosed by a closed surface, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains.