65 relations: Ancient Greek astronomy, Angle, Archimedes, Aristarchus of Samos, Aristyllus, Astronomer, Astronomy, Babylonian astronomy, Brady Haran, Calendar, Chord (geometry), Compass, Day, Decimal degrees, Degree (angle), Degree symbol, Dirghatamas, Divisor, Ecliptic, Equilateral triangle, Eratosthenes, Geographic coordinate system, Gradian, Hewlett-Packard, Highly composite number, Hipparchus, History of trigonometry, Hour, India, Indirect fire, International System of Units, Iranian calendars, Jamshīd al-Kāshī, Latitude, Least common multiple, Longitude, Mathematical constant, Mathematics, MathWorld, Meridian arc, Metric system, Milliradian, Minute and second of arc, Non-SI units mentioned in the SI, Pi, Plane (geometry), Prime (symbol), Quotation mark, Radian, Rigveda, ..., Roman numerals, Rowohlt Verlag, Saint Petersburg, Scientific calculator, Sexagesimal, Solid angle, Square degree, Steradian, Time zone, Timocharis, Trigonometric functions, Turn (geometry), Unit of measurement, University of Nottingham, 2520 (number). Expand index (15 more) » « Shrink index
Greek astronomy is astronomy written in the Greek language in classical antiquity.
In plane geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle.
Archimedes of Syracuse (Ἀρχιμήδης) was a Greek mathematician, physicist, engineer, inventor, and astronomer.
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).
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.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
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.
Brady John Haran (born 18 June 1976) is an Australian-born British independent filmmaker and video journalist who is known for his educational videos and documentary films produced for BBC News and his YouTube channels, the most notable being Periodic Videos and Numberphile.
A calendar is a system of organizing days for social, religious, commercial or administrative purposes.
A chord of a circle is a straight line segment whose endpoints both lie on the circle.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions (or points).
A day, a unit of time, is approximately the period of time during which the Earth completes one rotation with respect to the Sun (solar day).
Decimal degrees (DD) express latitude and longitude geographic coordinates as decimal fractions and are used in many geographic information systems (GIS), web mapping applications such as OpenStreetMap, and GPS devices.
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.
The degree symbol (°) is a typographical symbol that is used, among other things, to represent degrees of arc (e.g. in geographic coordinate systems), hours (in the medical field), degrees of temperature, alcohol proof, or diminished quality in musical harmony.
Dīrghatamas (Sanskrit: दीर्घतमस्) was an ancient sage well known for his philosophical verses in the RgVeda.
In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible by another integer m if m is a divisor of n; this implies dividing n by m leaves no remainder.
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.
In geometry, an equilateral triangle is a triangle in which all three sides are equal.
Eratosthenes of Cyrene (Ἐρατοσθένης ὁ Κυρηναῖος,; –) was a Greek mathematician, geographer, poet, astronomer, and music theorist.
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 gradian is a unit of measurement of an angle, equivalent to \frac of a turn, \frac of a degree, or \frac of a radian.
The Hewlett-Packard Company (commonly referred to as HP) or shortened to Hewlett-Packard was an American multinational information technology company headquartered in Palo Alto, California.
A highly composite number (or anti-prime) is a positive integer with more divisors than any smaller positive integer has.
Hipparchus of Nicaea (Ἵππαρχος, Hipparkhos) was a Greek astronomer, geographer, and mathematician.
Early study of triangles can be traced to the 2nd millennium BC, in Egyptian mathematics (Rhind Mathematical Papyrus) and Babylonian mathematics.
An hour (symbol: h; also abbreviated hr.) is a unit of time conventionally reckoned as of a day and scientifically reckoned as 3,599–3,601 seconds, depending on conditions.
India (IAST), also called the Republic of India (IAST), is a country in South Asia.
Indirect fire is aiming and firing a projectile without relying on a direct line of sight between the gun and its target, as in the case of direct fire.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
The Iranian calendars (گاهشماری ایرانی Gâhshomâriye Irâni) are a succession of calendars invented or used for over two millennia in Iran (Persia).
Ghiyāth al-Dīn Jamshīd Masʿūd al-Kāshī (or al-Kāshānī) (غیاث الدین جمشید کاشانی Ghiyās-ud-dīn Jamshīd Kāshānī) (c. 1380 Kashan, Iran – 22 June 1429 Samarkand, Transoxania) was a Persian astronomer and mathematician.
In geography, latitude is a geographic coordinate that specifies the north–south position of a point on the Earth's surface.
In arithmetic and number theory, the least common multiple, lowest common multiple, or smallest common multiple of two integers a and b, usually denoted by LCM(a, b), is the smallest positive integer that is divisible by both a and b. Since division of integers by zero is undefined, this definition has meaning only if a and b are both different from zero.
Longitude, is a geographic coordinate that specifies the east-west position of a point on the Earth's surface.
A mathematical constant is a special number that is "significantly interesting in some way".
Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") is the study of such topics as quantity, structure, space, and change.
MathWorld is an online mathematics reference work, created and largely written by Eric W. Weisstein.
In geodesy, a meridian arc measurement is the distance between two points with the same longitude, i.e., a segment of a meridian curve or its length.
The metric system is an internationally adopted decimal system of measurement.
A milliradian, often called a mil or mrad, is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian).
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
This is a list of units that are not defined as part of the International System of Units (SI), but are otherwise mentioned in the SI, because either the General Conference on Weights and Measures (CGPM) accepts their use as being multiples or submultiples of SI-units, they have important contemporary application worldwide, or are otherwise commonly encountered worldwide.
The number is a mathematical constant.
In mathematics, a plane is a flat, two-dimensional surface that extends infinitely far.
The prime symbol (′), double prime symbol (&Prime), triple prime symbol (‴), quadruple prime symbol (⁗) etc., are used to designate units and for other purposes in mathematics, the sciences, linguistics and music.
Quotation marks, also called quotes, quote marks, quotemarks, speech marks, inverted commas or talking marks, are punctuation marks used in pairs in various writing systems to set off direct speech, a quotation, or a phrase.
The radian (SI symbol rad) is the SI unit for measuring angles, and is the standard unit of angular measure used in many areas of mathematics.
The Rigveda (Sanskrit: ऋग्वेद, from "praise" and "knowledge") is an ancient Indian collection of Vedic Sanskrit hymns along with associated commentaries on liturgy, ritual and mystical exegesis.
The numeric system represented by Roman numerals originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages.
Rowohlt Verlag is a publishing house based in Reinbek and also Hamburg and Berlin, part of the Georg von Holtzbrinck Group (since 1982).
Saint Petersburg (p) is Russia's second-largest city after Moscow, with 5 million inhabitants in 2012, part of the Saint Petersburg agglomeration with a population of 6.2 million (2015).
A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science, engineering, and mathematics.
Sexagesimal (base 60) is a numeral system with sixty as its base.
In geometry, a solid angle (symbol) is a measure of the amount of the field of view from some particular point that a given object covers.
A square degree (deg2) is a non-SI-compliant unit measure of solid angle.
A time zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes.
Timocharis of Alexandria (Τιμόχαρις or Τιμοχάρης, gen. Τιμοχάρους; c. 320–260 BC) was a Greek astronomer and philosopher.
In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are functions of an angle.
A turn is a unit of plane angle measurement equal to 2pi radians, 360 degrees or 400 gradians.
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity.
The University of Nottingham is a public research university in Nottingham, United Kingdom.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.
2520 (two thousand five hundred twenty) is the natural number following 2519 and preceding 2521.
Altgrad, Angular degree, Arc degree, Arc degrees, Arc-degree, Arcdegree, Arcdegrees, Bogengrad, DEG (calculator mode), Decadegree, Degree (geometry), Degree (unit of angle), Degree of arc, Degrees of arc, Fourth (angle), Sexagesimal degree, Third (angle).