The following

outline Outline or outlining may refer to: * Outline (list), a document summary, in hierarchical list format * Code folding, a method of hiding or collapsing code or text to see content in outline form * Outline drawing, a sketch depicting the outer edge ...

is provided as an overview of and topical guide to astronomy:

Astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

– studies the

universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...

beyond Earth, including its formation and development, and the evolution,

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

, and

motion In physics, motion is when an object changes its position with respect to a reference point in a given time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and frame of reference to an o ...

celestial objects An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...

(such as

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

s, etc.) and

phenomena A phenomenon ( phenomena), sometimes spelled phaenomenon, is an observable Event (philosophy), event. The term came into its modern Philosophy, philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be ...

that originate outside the

atmosphere of Earth The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weather ...

(such as the

cosmic background radiation Cosmic background radiation is electromagnetic radiation that fills all space. The origin of this radiation depends on the region of the spectrum that is observed. One component is the cosmic microwave background. This component is redshifted ...

). Astronomy also intersects with biology, as

astrobiology Astrobiology (also xenology or exobiology) is a scientific field within the List of life sciences, life and environmental sciences that studies the abiogenesis, origins, Protocell, early evolution, distribution, and future of life in the univ ...

, studying potential life throughout the universe.

Nature of astronomy

Astronomy can be described as all the following: * An

academic discipline An academic discipline or academic field is a subdivision of knowledge that is taught and researched at the college or university level. Disciplines are defined (in part) and recognized by the academic journals in which research is published, a ...

: one with academic departments, curricula and degrees; national and international societies; and specialized journals. * A scientific field (a branch of

science Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which stu ...

) – widely recognized category of specialized expertise within science, and typically embodies it ** A

natural science Natural science or empirical science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer ...

– one that seeks to elucidate the rules that govern the

natural Nature is an inherent character or constitution, particularly of the ecosphere or the universe as a whole. In this general sense nature refers to the laws, elements and phenomena of the physical world, including life. Although humans are part ...

world using

empirical Empirical evidence is evidence obtained through sense experience or experimental procedure. It is of central importance to the sciences and plays a role in various other fields, like epistemology and law. There is no general agreement on how t ...

and

scientific method The scientific method is an Empirical evidence, empirical method for acquiring knowledge that has been referred to while doing science since at least the 17th century. Historically, it was developed through the centuries from the ancient and ...

s. *** A branch or field of

space science Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless ...

* A hobby or part-time pursuit for the satisfaction of personal

curiosity Curiosity (from Latin , from "careful, diligent, curious", akin to "care") is a quality related to inquisitive thinking, such as exploration, investigation, and learning, evident in humans and other animals. Curiosity helps Developmental psyc ...

or appreciation of

beauty Beauty is commonly described as a feature of objects that makes them pleasure, pleasurable to perceive. Such objects include landscapes, sunsets, humans and works of art. Beauty, art and taste are the main subjects of aesthetics, one of the fie ...

, the latter especially including

astrophotography Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1839, but it was no ...

Branches

Astrobiology Astrobiology (also xenology or exobiology) is a scientific field within the List of life sciences, life and environmental sciences that studies the abiogenesis, origins, Protocell, early evolution, distribution, and future of life in the univ ...

– studies the advent and

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

biological system A biological system is a complex Biological network inference, network which connects several biologically relevant entities. Biological organization spans several scales and are determined based different structures depending on what the system is ...

s in the universe. *

Astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...

– branch of

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

that deals with the

of the universe, including the physical properties of celestial objects, as well as their interactions and behavior. Among the objects studied are galaxies,

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

s, planets,

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...

s, the

interstellar medium The interstellar medium (ISM) is the matter and radiation that exists in the outer space, space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as cosmic dust, dust and cosmic rays. It f ...

and the

cosmic microwave background The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dar ...

; and the properties examined include

luminosity Luminosity is an absolute measure of radiated electromagnetic radiation, electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electroma ...

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

, and

chemical A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

composition. The subdisciplines of theoretical astrophysics are: ** Compact objects – this subdiscipline studies very dense matter in

white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...

s and

neutron star A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...

s and their effects on environments including

accretion Accretion may refer to: Science * Accretion (astrophysics), the formation of planets and other bodies by collection of material through gravity * Accretion (meteorology), the process by which water vapor in clouds forms water droplets around nucl ...

. **

Physical cosmology Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fu ...

– origin and evolution of the universe as a whole. The study of cosmology is theoretical astrophysics at its largest scale. **

Quantum cosmology Quantum cosmology is the attempt in theoretical physics to develop a quantum theory of the universe. This approach attempts to answer open questions of classical physical cosmology, particularly those related to the first phases of the universe. ...

- the study of cosmology through the use of

quantum field theory In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines Field theory (physics), field theory and the principle of relativity with ideas behind quantum mechanics. QFT is used in particle physics to construct phy ...

to explain phenomena

general relativity General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...

cannot due to limitations in its framework. **

Computational astrophysics Computational astrophysics refers to the methods and computing tools developed and used in astrophysics research. Like computational chemistry or computational physics, it is both a specific branch of theoretical astrophysics and an interdiscip ...

– The study of astrophysics using computational methods and tools to develop computational models. **

Galactic astronomy Galactic astronomy is the study of the Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies. Galactic astronomy should not be con ...

– deals with the structure and components of our Galaxy and of other galaxies. ** High energy astrophysics – studies phenomena occurring at high energies including

active galactic nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such e ...

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant Galaxy, galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme Electromagnetic radiation, ele ...

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

s, and

shock Shock may refer to: Common uses Healthcare * Acute stress reaction, also known as psychological or mental shock ** Shell shock, soldiers' reaction to battle trauma * Circulatory shock, a medical emergency ** Cardiogenic shock, resulting from ...

s. ** Interstellar astrophysics – study of the

intergalactic medium Intergalactic may refer to: * "Intergalactic" (song), a song by the Beastie Boys * ''Intergalactic'' (TV series), a 2021 UK science fiction TV series * Intergalactic space * Intergalactic travel, travel between galaxies in science fiction and ...

and

dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...

. **

Extragalactic astronomy Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. The closest objects in extragalactic ...

– study of objects (mainly galaxies) outside our Galaxy, including

galaxy formation and evolution In cosmology, the study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the process ...

. **

Stellar astronomy Astronomy is a natural science that studies astronomical object, celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall chronology of the U ...

– concerned with

Star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

, physical properties,

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

life span,

variability Variability is how spread out or closely clustered a set of data is. Variability may refer to: Biology *Genetic variability, a measure of the tendency of individual genotypes in a population to vary from one another *Heart rate variability, a phy ...

stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is consi ...

and extinction. **

Plasma astrophysics Astrophysical plasma is plasma (physics), plasma outside of the Solar System. It is studied as part of astrophysics and is commonly observed in space. The accepted view of scientists is that much of the baryonic matter in the universe exists in th ...

– studies properties of plasma in outer space. **

Relativistic astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...

– studies effects of

special relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory of the relationship between Spacetime, space and time. In Albert Einstein's 1905 paper, Annus Mirabilis papers#Special relativity, "On the Ele ...

and

in astrophysical contexts including

gravitational waves Gravitational waves are oscillations of the gravitational field that travel through space at the speed of light; they are generated by the relative motion of gravitating masses. They were proposed by Oliver Heaviside in 1893 and then later by H ...

gravitational lens A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

ing and

black hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

s. **

Solar physics Solar physics is the branch of astrophysics that specializes in the study of the Sun. It intersects with many disciplines of pure physics and astrophysics. Because the Sun is uniquely situated for close-range observing (other stars cannot be re ...

– Sun and its interaction with the remainder of the Solar System and interstellar space. *

Planetary Science Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of ...

– study of planets, moons, and planetary systems. **

Atmospheric science Atmospheric science is the study of the Atmosphere of Earth, Earth's atmosphere and its various inner-working physical processes. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather forecasting. Clima ...

– study of atmospheres and weather. **

Exoplanetology This page describes exoplanet orbital and physical parameters. Orbital parameters Most known extrasolar planet candidates have been discovered using indirect methods and therefore only some of their physical and orbital parameters can be determi ...

– various planets outside of the Solar System **

Planetary formation The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting t ...

– formation of planets and moons in the context of the

formation and evolution of the Solar System There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. Most of the collapsing mass collected in the center, forming the Sun, while ...

. **

Planetary rings A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as dust, meteoroids, planetoids, moonlets, or stellar objects. Ring systems are best known as planetary rings, common components of sate ...

– dynamics, stability, and composition of planetary rings **

Magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior Dynamo ...

s – magnetic fields of planets and moons **

Planetary surface A planetary surface is where the solid or liquid material of certain types of astronomical objects contacts the atmosphere or outer space. Planetary surfaces are found on solid objects of planetary mass, including terrestrial planets (including ...

s – surface geology of planets and moons ** Planetary interiors – interior composition of planets and moons **

Small Solar System bodies A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first IAU definition of planet, defined in 2006 by the International Astronomical Union (IAU) as fo ...

– smallest bodies, including

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

Kuiper belt object The Kuiper belt ( ) is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...

s, and dust. * Astronomy divided by general technique used for astronomical research: **

Astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...

– study of the position of objects in the sky and their changes of position. Defines the system of coordinates used and the

kinematics In physics, kinematics studies the geometrical aspects of motion of physical objects independent of forces that set them in motion. Constrained motion such as linked machine parts are also described as kinematics. Kinematics is concerned with s ...

of objects in our Galaxy. **

Observational astronomy Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical ...

– practice of observing celestial objects by using telescopes and other astronomical apparatus. It is concerned with recording data. The subdisciplines of

observational astronomy Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical ...

are generally made by the specifications of the detectors, specifically the ranges of wavelengths observed: ***

Radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...

– Above 300 μm ***

Submillimetre astronomy Submillimetre astronomy or submillimeter astronomy (see spelling differences) is the branch of observational astronomy that is conducted at submillimetre wavelengths (i.e., terahertz radiation) of the electromagnetic spectrum. Astronomers plac ...

– 200 μm to 1 mm ***

Infrared astronomy Infrared astronomy is a sub-discipline of astronomy which specializes in the astronomical observation, observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 microm ...

– 0.7–350 μm ***

Optical astronomy Visible-light astronomy encompasses a wide variety of astronomical observation via telescopes that are sensitive in the range of visible light (optical telescopes). Visible-light astronomy is part of optical astronomy, and differs from astronomi ...

– 380–750 nm ***

Ultraviolet astronomy Ultraviolet astronomy is the observation of electromagnetic radiation at ultraviolet wavelengths between approximately 10 and 320 nanometres; shorter wavelengths—higher energy photons—are studied by X-ray astronomy and gamma-ray astro ...

– 10–320 nm ***

X-ray astronomy X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to ...

– 0.01–10 nm ***

Gamma-ray astronomy Gamma-ray astronomy is a subfield of astronomy where scientists observe and study celestial objects and phenomena in outer space which emit cosmic electromagnetic radiation in the form of gamma rays,Astronomical literature generally hyphena ...

– Below 0.01 nm *** Cosmic ray astronomy –

Cosmic ray Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the ...

s, including plasma ***

Neutrino astronomy Neutrino astronomy is a branch of astronomy that gathers information about astronomical objects by observing and studying neutrinos emitted by them with the help of neutrino detectors in special Earth observatories. It is an emerging field in as ...

–

Neutrino A neutrino ( ; denoted by the Greek letter ) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that i ...

s *** Dust astronomy –

Cosmic dust Cosmic dustalso called extraterrestrial dust, space dust, or star dustis dust that occurs in outer space or has fallen onto Earth. Most cosmic dust particles measure between a few molecules and , such as micrometeoroids (30 μm). Cosmic dust can ...

***

Gravitational wave astronomy Gravitational-wave astronomy is a subfield of astronomy concerned with the detection and study of gravitational waves emitted by astrophysical sources. Gravitational waves are minute distortions or ripples in spacetime caused by the acceleration ...

–

Graviton In theories of quantum gravity, the graviton is the hypothetical elementary particle that mediates the force of gravitational interaction. There is no complete quantum field theory of gravitons due to an outstanding mathematical problem with re ...

s **

Photometry Photometry can refer to: * Photometry (optics), the science of measurement of visible light in terms of its perceived brightness to human vision * Photometry (astronomy), the measurement of the flux or intensity of an astronomical object's electr ...

– study of how bright celestial objects are when passed through different filters **

Spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...

– study of the spectra of astronomical objects * Other disciplines that may be considered part of astronomy: **

Archaeoastronomy Archaeoastronomy (also spelled archeoastronomy) is the interdisciplinary or multidisciplinary study of how people in the past "have understood the phenomena in the sky, how they used these phenomena and what role the sky played in their cultur ...

Astrochemistry Astrochemistry is the study of the abundance and reactions of molecules in the universe, and their interaction with radiation. The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar Syst ...

History

History of astronomy The history of astronomy focuses on the contributions civilizations have made to further their understanding of the universe beyond earth's atmosphere. Astronomy is one of the oldest natural sciences, achieving a high level of success in the sec ...

* History of the Center of the Universe **

Geocentric model In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded scientific theories, superseded description of the Universe with Earth at the center. Under most geocentric m ...

Heliocentrism Heliocentrism (also known as the heliocentric model) is a superseded astronomical model in which the Earth and planets orbit around the Sun at the center of the universe. Historically, heliocentrism was opposed to geocentrism, which placed t ...

***

Copernican heliocentrism Copernican heliocentrism is the astronomical scientific modeling, model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting arou ...

***

Tychonic system The Tychonic system (or Tychonian system) is a model of the universe published by Tycho Brahe in 1588, which combines what he saw as the mathematical benefits of the Copernican heliocentrism, Copernican system with the philosophical and "physic ...

Archaeoastronomy and Vedic chronology Modern authors have attempted to date the Vedic period based on archaeoastronomical calculations. In the 18th century William Jones tried to show, based on information gathered from Varaha Mihira, that Parashara muni lived at 1181 BCE. See also * ...

* Pretelescopic astronomy **

Babylonian astronomy Babylonian astronomy was the study or recording of celestial objects during the early history of Mesopotamia. The numeral system used, sexagesimal, was based on 60, as opposed to ten in the modern decimal system. This system simplified the ca ...

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The Ancient China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...

Egyptian astronomy Egyptian astronomy started in prehistory, prehistoric times, in the Prehistoric Egypt, Predynastic Period. In the 5th millennium BCE, the stone circles at Nabta Playa may have made use of astronomical alignments. By the time the historical Ancie ...

Greek astronomy Ancient Greek astronomy is the astronomy written in the Greek language during classical antiquity. Greek astronomy is understood to include the Ancient Greece, Ancient Greek, Hellenistic period, Hellenistic, Roman Empire, Greco-Roman, and Late an ...

Hebrew astronomy Hebrew astronomy refers to any astronomy written in Hebrew or by Hebrew speakers, or translated into Hebrew, or written by Jews in Judeo-Arabic. It includes a range of genres from the earliest astronomy and cosmology contained in the Bible, mainly ...

Indian astronomy Astronomy has a long history in the Indian subcontinent, stretching from History of India, pre-historic to History of India (1947–present), modern times. Some of the earliest roots of Indian astronomy can be dated to the period of Indus Valle ...

Islamic astronomy Medieval Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries), and mostly written in the Arabic language. These developments mostly took place in th ...

** Russian astronomy ** Astronomy in the Middle Ages *** Science in Medieval Western Europe ***

Astronomy in medieval Islam Medieval Islamic astronomy comprises the Astronomy, astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries), and mostly written in the Arabic language. These developments mostly took ...

* History of astronomy in the Renaissance ** Scientific developments during the Scientific Revolution *** Patronage in astronomy ***

Copernican Revolution The term "Copernican Revolution" was coined by the German philosopher Immanuel Kant in his 1781 work ''Critique of Pure Reason''. It was the paradigm shift from the Ptolemaic model of the heavens, which described the cosmos as having Earth sta ...

****

Nicolaus Copernicus Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...

***** ''

On the Revolutions of the Heavenly Spheres ''De revolutionibus orbium coelestium'' (English translation: ''On the Revolutions of the Heavenly Spheres'') is the seminal work on the Copernican heliocentrism, heliocentric theory of the astronomer Nicolaus Copernicus (1473–1543) of the Rena ...

'' ****

Tycho Brahe Tycho Brahe ( ; ; born Tyge Ottesen Brahe, ; 14 December 154624 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations. He ...

*****

****

Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

***** ''

Dialogue Concerning the Two Chief World Systems ''Dialogue Concerning the Two Chief World Systems'' (''Dialogo sopra i due massimi sistemi del mondo'') is a 1632 book by Galileo Galilei comparing Nicolaus Copernicus's Copernican heliocentrism, heliocentric system model with Ptolemy's geocen ...

'' defense of the heliocentric system written by Galileo, which led to his trial and house arrest by the Inquisition. ***

Invention of the telescope The history of the telescope can be traced to before the invention of the earliest known telescope, which appeared in 1608 in the Netherlands, when a patent was submitted by Hans Lippershey, an eyeglass maker. Although Lippershey did not recei ...

**** History of visible-light astronomy * History of astronomy in the Age of Reflection * * History of X-ray astronomy * History of infrared astronomy * History of gamma-ray astronomy *

History of supernova observation The known history of supernova observation goes back to 1006 AD. All earlier proposals for supernova observations are speculations with many alternatives. Since the development of the telescope, the field of supernova discovery has expanded to o ...

List of supernovae A supernova is an event in which a star destroys itself in an explosion which can briefly become as luminous as an entire galaxy. This list of supernovas of historical significance includes events that were observed prior to the development of pho ...

Basic astronomical phenomena

Atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

Celestial pole The north and south celestial poles are the two points in the sky where Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently directly overhead to observers at ...

Eclipse An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ...

Ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

Cosmic rays Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar ...

Kepler's laws In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler in 1609 (except the third law, which was fully published in 1619), describe the orbits of planets around the Sun. These laws replaced circular orbits and epicycles in ...

Doppler effect The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described ...

Nutation Nutation () is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behaviour of a mechanism. In an appropriate reference fra ...

Orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

Perturbation Perturbation or perturb may refer to: * Perturbation theory, mathematical methods that give approximate solutions to problems that cannot be solved exactly * Perturbation (geology), changes in the nature of alluvial deposits over time * Perturbati ...

Precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In o ...

Proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

Redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

Solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...

Tides Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

Zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...

Astronomical objects

Astronomical object An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...

Solar System

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

Geology of solar terrestrial planets The geology of solar terrestrial planets mainly deals with the geological aspects of the four terrestrial planets of the Solar System – Mercury, Venus, Earth, and Mars – and one terrestrial dwarf planet: Ceres. Earth is the only terrestria ...

List of Solar System objects The following is a list of Solar System objects by orbit, ordered by increasing distance from the Sun. Most named objects in this list have a diameter of 500 km or more. *The Sun, a spectral class G2V main-sequence star *The inner Solar Sy ...

List of Solar System objects by size This article includes a list of the most massive known objects of the Solar System and partial lists of smaller objects by observed mean radius. These lists can be sorted according to an object's radius and mass and, for the most massive objects, ...

Galilean satellites The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede, Callisto, Io, and Europa. They are the most readily visible Solar System objects after Saturn, the dimmest of ...

Halley's comet Halley's Comet is the only known List of periodic comets, short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after ...

Sun

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

* Location **

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

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Stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

** * Internal structure ** Standard Solar Model **

Solar core The core of the Sun is considered to extend from the center to about 0.2 of the solar radius (). It is the hottest part of the Sun and of the Solar System. It has a density of at the center, and a temperature of 15 million kelvins (15 million de ...

Radiation zone A radiative zone is a layer of a star's interior where energy is primarily transported toward the exterior by means of radiative diffusion and thermal conduction, rather than by convection. Energy travels through the radiative zone in the form of ...

Convection zone A convection zone, convective zone or convective region of a star is a layer which is unstable due to convection. Energy is primarily or partially transported by convection in such a region. In a radiation zone, energy is transported by radiation ...

Stellar atmosphere The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. Overview The stellar atmosphere is divided into several regions of distinct character: * The photosphere, whi ...

Photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

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Supergranulation In solar physics and observation, supergranulation is a pattern of convection cells in the Sun's photosphere. The individual convection cells are typically referred to as supergranules. The pattern was discovered in the 1950s by A.B. Hart using Do ...

*** Granule ***

Facula Facula ( faculae) is a bright spot on the surface of a planet or a star. It may refer to * Solar facula Solar faculae are bright spots in the photosphere that form in the canyons between solar granules, short-lived convection cells several tho ...

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Sunspot Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually aff ...

Chromosphere A chromosphere ("sphere of color", from the Ancient Greek words χρῶμα (''khrôma'') 'color' and σφαῖρα (''sphaîra'') 'sphere') is the second layer of a Stellar atmosphere, star's atmosphere, located above the photosphere and below t ...

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Plage Plage may refer to: *Solar plage, a bright region in the chromosphere of the Sun *Plage (mycology), a clear, unornamented area on the basal area of an ornamented fungal spore * "Plage" (song), a 2011 song by English electronic band Crystal Fighter ...

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Spicule Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ...

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Moreton wave A Moreton wave, Solar Tsunami, or Moreton-Ramsey wave is the chromospheric signature of a large-scale solar corona shock wave. Described as a kind of solar "tsunami", they are generated by solar flares. They are named for American astronomer G ...

Solar corona In astronomy, a corona (: coronas or coronae) is the outermost layer of a star's Stellar atmosphere, atmosphere. It is a hot but relatively luminosity, dim region of Plasma (physics), plasma populated by intermittent coronal structures such as so ...

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Solar transition region The solar transition region is a region of the Sun's atmosphere between the upper chromosphere and corona. It is important because it is the site of several unrelated but important transitions in the physics of the solar atmosphere: * Below, gr ...

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Coronal hole Coronal holes are regions of the Sun's corona that emit low levels of ultraviolet and X-ray radiation compared to their surroundings. They are composed of relatively cool and tenuous plasma (physics), plasma permeated by magnetic fields that are o ...

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Coronal loop In solar physics, a coronal loop is a well-defined arch-like structure in the Sun's Stellar atmosphere, atmosphere made up of relatively dense Plasma (physics), plasma confined and isolated from the surrounding medium by magnetic flux tubes. Co ...

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Coronal mass ejection A coronal mass ejection (CME) is a significant ejection of plasma mass from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understandin ...

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Solar prominence In solar physics, a prominence, sometimes referred to as a filament, is a large Plasma (physics), plasma and magnetic field structure extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface ...

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Helmet streamer Helmet streamers, also known as coronal streamers, are elongated cusp-like structures in the Sun's corona which are often visible in white-light coronagraphs and during solar eclipses. They are closed magnetic loops which lie above divisions betw ...

Solar variation The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of variations in the number of observed sunspots on the Sun's surface. ...

Solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...

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List of solar cycles Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised In ...

Solar maximum Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. On average, the solar cycle take ...

Solar minimum Solar minimum is the regular period of least solar activity in the Sun's 11-year solar cycle. During solar minimum, sunspot and solar flare activity diminishes, and often does not occur for days at a time. On average, the solar cycle takes about ...

Wolf number The Wolf number (also known as the relative sunspot number or Zürich number) is a quantity that measures the number of sunspots and groups of sunspots present on the surface of the Sun. Historically, it was only possible to detect sunspots on t ...

Solar flare A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and ot ...

Helioseismology Helioseismology is the study of the structure and dynamics of the Sun through its oscillations. These are principally caused by sound waves that are continuously driven and damped by convection near the Sun's surface. It is similar to geoseismol ...

Heliosphere The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, tailed bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding ...

Solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

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Heliospheric current sheet The heliospheric current sheet, or interplanetary current sheet, is a surface separating regions of the heliosphere where the interplanetary magnetic field points toward and away from the Sun. A small electrical current with a current density of ...

** ** ** Heliopause **

Bow shock In astrophysics, bow shocks are shock waves in regions where the conditions of density and pressure change dramatically due to blowing stellar wind. Bow shock occurs when the magnetosphere of an astrophysical object interacts with the nearby fl ...

* Related phenomena **

Solar dynamo The solar dynamo is a physical process that generates the Sun's magnetic field. It is explained with a variant of the dynamo theory. A naturally occurring electric generator in the Sun's interior produces electric currents and a magnetic field, ...

Sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

Solar energy Solar energy is the radiant energy from the Sun's sunlight, light and heat, which can be harnessed using a range of technologies such as solar electricity, solar thermal energy (including solar water heating) and solar architecture. It is a ...

* Equipment used to study the Sun **

Solar telescope A solar telescope or a solar observatory is a special-purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include helio ...

Planets

Planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

** Features ***

Natural satellite A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, a deriv ...

s (moons) ***

Planetary ring A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as dust, meteoroids, planetoids, moonlets, or stellar objects. Ring systems are best known as planetary rings, common components of sate ...

s * Planets of the Solar System ** Mercury **

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

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Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

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Moons of Mars The two natural satellite, moons of Mars (planet), Mars are Phobos (moon), Phobos and Deimos (moon), Deimos. They are irregular in shape. Both were discovered by American astronomer Asaph Hall in August 1877 and are named after the Greek mytholo ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

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Moons of Jupiter There are 97 Natural satellite, moons of Jupiter with confirmed orbits . This number does not include a number of meter-sized moonlets thought to be shed from the inner moons, nor hundreds of possible kilometer-sized outer irregular moons that ...

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Rings of Jupiter The rings of Jupiter are a system of faint planetary rings. The Jovian rings were the third ring system to be discovered in the Solar System, after those of Saturn and Uranus. The main ring was discovered in 1979 by the ''Voyager 1'' space probe ...

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

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Moons of Saturn The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to the enormous Titan (moon), Titan, which is larger than the planet Mercury (planet), Mercury. There are 274 natural satellite, moons with con ...

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Rings of Saturn Saturn has the most extensive and complex ring system of any planet in the Solar System. The rings consist of particles in orbit around the planet made almost entirely of water ice, with a trace component of Rock (geology), rocky material. Parti ...

Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...

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Moons of Uranus Uranus, the seventh planet of the Solar System, has 28 confirmed moons. The 27 with names are named after characters that appear in, or are mentioned in, William Shakespeare's plays and Alexander Pope's poem '' The Rape of the Lock''. Uranus's ...

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Rings of Uranus The rings of Uranus consists of 13 planetary rings. They are intermediate in complexity between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. The rings of Uranus were discovered on March 10, 1977, by J ...

Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...

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Moons of Neptune The planet Neptune has 16 known natural satellite, moons, which are named for minor List of water deities, water deities and a Hippocampus (mythology), water creature in Greek mythology.This is a IAU guideline that will be followed at the naming ...

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Rings of Neptune The rings of Neptune consist primarily of five principal Planetary ring, rings. They were first discovered (as "arcs") by simultaneous observations of a stellar occultation on 22 July 1984 by André Brahic's and William B. Hubbard's teams at La S ...

Dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...

s of the Solar System **

Ceres Ceres most commonly refers to: * Ceres (dwarf planet), the largest asteroid and first to be discovered * Ceres (mythology), the Roman goddess of agriculture Ceres may also refer to: Places Brazil * Ceres, Goiás, Brazil * Ceres Microregion ...

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...

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Moons of Pluto The dwarf planet Pluto has five natural satellites. In order of distance from Pluto, they are Charon, Styx, Nix, Kerberos, and Hydra. Charon, the largest, is mutually tidally locked with Pluto, and is massive enough that Pluto and Charon ar ...

Haumea Haumea ( minor-planet designation: 136108 Haumea) is a dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory, and formally announced in 2005 by a team heade ...

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Moons of Haumea The dwarf planet Haumea has two known moons, Hiiaka and Namaka, named after Hawaiian goddesses. These small moons were discovered in 2005, from observations of Haumea made at the large telescopes of the W. M. Keck Observatory in Hawaii. H ...

Makemake Makemake ( minor-planet designation: 136472 Makemake) is a dwarf planet and the largest of what is known as the classical population of Kuiper belt objects, with a diameter approximately that of Saturn's moon Iapetus, or 60% that of Pluto. It ...

** Eris *** Dysnomia

Small Solar System bodies

Small Solar System body A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union (IAU) as follows: "All other objects ...

Asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

s **

Minor planets According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

** :Asteroid groups and families ***

Vulcanoid asteroid The vulcanoids are a List of hypothetical Solar System objects, hypothetical population of asteroids that orbit the Sun in a dynamically stable zone inside the orbit of the planet Mercury (planet), Mercury. They are named after the hypothetical p ...

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Near-Earth asteroid A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun (perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit aro ...

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Asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

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Trojan asteroid In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points and . Trojans can shar ...

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Centaur A centaur ( ; ; ), occasionally hippocentaur, also called Ixionidae (), is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse that was said to live in the mountains of Thessaly. In one version o ...

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Neptune Trojan Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets. They therefore have approximately the same orbital period as Neptune and follow roughly the same orbita ...

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Minor planet moon A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. , there are 457 minor planets known or suspected to have moons. Discoveries of minor-planet moons (and binary objects, in general) are important ...

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Meteoroids A meteoroid ( ) is a small rocky or metallic body in outer space. Meteoroids are distinguished as objects significantly smaller than ''asteroids'', ranging in size from grains to objects up to wide. Objects smaller than meteoroids are classifie ...

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2 Pallas Pallas (minor-planet designation: 2 Pallas) is the List of largest asteroids, third-largest asteroid in the Solar System by volume and mass. It is the second asteroid to have been discovered, after 1 Ceres, Ceres, and is likely a remnant ...

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3 Juno Juno (minor-planet designation: 3 Juno) is a large asteroid in the asteroid belt. Juno was the third asteroid discovered, in 1804, by German astronomer Karl Harding. It is tied with three other asteroids as the thirteenth largest asteroid, and ...

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4 Vesta Vesta (minor-planet designation: 4 Vesta) is one of the largest objects in the asteroid belt, with a mean diameter of . It was discovered by the German astronomer Heinrich Wilhelm Matthias Olbers on 29 March 1807 and is named after Vesta (mytho ...

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10 Hygiea 10 Hygiea is a large asteroid located in the outer main asteroid belt between the orbits of Mars and Jupiter. It was the tenth known asteroid, discovered on 12 April 1849 by Italian astronomer Annibale de Gasparis at the Astronomical Observa ...

List of asteroids The following is a list of minor planets in ascending numerical order. Minor planets are small bodies in the Solar System: asteroids, distant objects, and dwarf planets, but not comets. As of 2022, the vast majority (97.3%) are asteroids from ...

Meanings of asteroid names This is a list of minor planets which have been officially named by the Working Group for Small Bodies Nomenclature (WGSBN) of the International Astronomical Union (IAU). The list consists of partial pages, each covering a number range of 1,000 bo ...

Trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (AU). ...

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Kuiper belt The Kuiper belt ( ) is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...

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Plutino In astronomy, the plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the la ...

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90482 Orcus Orcus (minor-planet designation: 90482 Orcus) is a dwarf planet located in the Kuiper belt, with one large moon, Vanth. It has an estimated diameter of , comparable to the Inner Solar System dwarf planet Ceres. The surface of Orcus is relativ ...

**** 28978 Ixion ***

Cubewano A classical Kuiper belt object, also called a cubewano ( "QB1-o"), is a low-eccentricity Kuiper belt object (KBO) that orbits beyond Neptune and is not controlled by an orbital resonance with Neptune. Cubewanos have orbits with semi-major axe ...

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20000 Varuna 20000 Varuna (provisional designation ) is a large trans-Neptunian object in the Kuiper belt. It was discovered in November 2000 by American astronomer Robert McMillan during a Spacewatch survey at the Kitt Peak National Observatory. It is na ...

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50000 Quaoar Quaoar ( minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper Belt, a ring of many icy planetesimals beyond Neptune. It has an elongated ellipsoidal shape with an average diameter of , about half the size of the d ...

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38628 Huya 38628 Huya ( ; provisional designation ) is a binary trans-Neptunian object located in the Kuiper belt, a region of icy objects orbiting beyond Neptune in the outer Solar System. Huya is classified as a plutino, a dynamical class of trans-Nept ...

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Scattered disc The scattered disc (or scattered disk) is a distant circumstellar disc in the Solar System that is sparsely populated by icy small Solar System bodies, which are a subset of the broader family of trans-Neptunian objects. The scattered-disc obj ...

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90377 Sedna Sedna ( minor-planet designation: 90377 Sedna) is a dwarf planet in the outermost reaches of the Solar System, orbiting the Sun far beyond the orbit of Neptune. Discovered in 2003, the frigid planetoid is one of the reddest known among Solar ...

Comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

s **

List of periodic comets Periodic comets (also known as short-period comets) are comets with orbital periods of less than 200 years or that have been observed during more than a single perihelion passage (e.g. 153P/Ikeya–Zhang). "Periodic comet" is also sometimes us ...

** List of non-periodic comets **

Damocloid Damocloids are a class of minor planets such as 5335 Damocles and 1996 PW that have Halley-type or long-period highly eccentric orbits typical of periodic comets such as Halley's Comet, but without showing a cometary coma or tail. David Jewi ...

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Hills cloud In astronomy, the Hills cloud (also called the inner Oort cloud and inner cloud) is a theoretical vast circumstellar disc, interior to the Oort cloud, whose outer border would be located at around 20,000 to 30,000 astronomical units (AU) fr ...

Oort cloud The Oort cloud (pronounced or ), sometimes called the Öpik–Oort cloud, is scientific theory, theorized to be a cloud of billions of Volatile (astrogeology), icy planetesimals surrounding the Sun at distances ranging from 2,000 to 200,000 A ...

Exoplanets

Exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...

(also known as extrasolar planets) – planet outside the Solar System. A total of 4,341 such planets have been identified as of 28 Jan 2021. **

Super-Earth A super-Earth is a type of exoplanet with a mass higher than Earth, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17.1 times Earth's, respectively. The term "super-Earth" refers only to t ...

– exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's

ice giant An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur. There are two ice giants in the Solar System: Uranus and Neptune. In astrophysics and planetary science ...

s. **

Mini-Neptune A Mini-Neptune (sometimes known as a gas dwarf or transitional planet) is a planet less massive than Neptune but resembling Neptune in that it has a thick hydrogen-helium atmosphere, probably with deep layers of ice, rock or liquid oceans (made o ...

– also known as a gas dwarf or transitional planet. A planet up to 10 Earth masses, but less massive than Uranus and Neptune. **

Super-Jupiter A super-Jupiter is a gas giant exoplanet that is more massive than the planet Jupiter. For example, substellar companion, companions at the planet–brown dwarf borderline have been called super-Jupiters, such as around the star Kappa Andromedae. ...

– an exoplanet more massive than

. **

Sub-Earth A sub-Earth is a planet "substantially less massive" than Earth and Venus. In the Solar System, this category includes Mercury (planet), Mercury and Mars. Characteristics Sub-Earth exoplanets are among the most difficult type to detect becau ...

– an exoplanet "substantially less massive" than Earth and

. ** Circumbinary planet – an exoplanet that orbits two stars. **

Hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e. Jupiter analogue, Jupiter analogues) but that have very short orbital periods (). The close proximity to t ...

– an exoplanet whose characteristics are similar to Jupiter, but that have high surface temperatures because they orbit very close to their parent stars, whereas Jupiter orbits its parent star (the

) at 5.2 AU (780×106 km), causing low surface temperatures. **

Hot Neptune A hot Neptune is a type of giant planet with a mass similar to that of Neptune or Uranus orbiting close to its star, normally within less than 1 AU. The first hot Neptune to be discovered with certainty was Gliese 436 b (Awohali) in 2007, an ex ...

– an exoplanet in an orbit close to its star (normally less than one astronomical unit away), with a mass similar to that of Uranus or Neptune. **

Pulsar planet Pulsar planets are planets that are orbiting pulsars. The first such planets to be discovered were around a millisecond pulsar in 1992 and were the first extrasolar planets to be confirmed as discovered. Pulsars are extremely precise clocks and ...

– a planet that orbits a pulsar or a rapidly rotating neutron star. **

Rogue planet A rogue planet, also termed a free-floating planet (FFP) or an isolated planetary-mass object (iPMO), is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf. Rogue planets may originate from ...

(also known as an interstellar planet) – a planetary-mass object that orbits the galaxy directly.

Stars and stellar objects

Fixed stars In astronomy, the fixed stars () are the luminary points, mainly stars, that appear not to move relative to one another against the darkness of the night sky in the background. This is in contrast to those lights visible to the naked eye, name ...

Stars

Stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is consi ...

** Pre–main sequence **

Main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

Horizontal branch The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha proc ...

Asymptotic giant branch The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) lat ...

Dredge-up A dredge-up is any one of several stages in the evolution of some stars. By definition, during a ''dredge-up'', a convection zone extends all the way from the star's surface down to the layers of material that have undergone fusion. Consequently, ...

Instability strip The unqualified term instability strip usually refers to a region of the Hertzsprung–Russell diagram largely occupied by several related classes of pulsating variable stars: Delta Scuti variables, SX Phoenicis variables, and rapidly oscillat ...

Red clump The red clump is a clustering of red giants in the Hertzsprung–Russell diagram at around 5,000 K and absolute magnitude (MV) +0.5, slightly hotter than most red-giant-branch stars of the same luminosity. It is visible as a denser region of ...

** PG 1159 star **

Mira variable Mira variables (named for the prototype star Mira) are a class of pulsating stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.5 magnitude at visual wave ...

Planetary nebula A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to planets. The ...

Protoplanetary nebula A protoplanetary nebula or preplanetary nebula (PPN, plural PPNe) is an astronomical object which is at the short-lived episode during a star's rapid evolution between the late asymptotic giant branch (LAGB) phase and the subsequent planetary ne ...

Luminous red nova A luminous red nova (abbr. ''LRN'', pl. ''luminous red novae'', pl.abbr. ''LRNe'') is a stellar explosion thought to be caused by the merging of two stars. They are characterised by a distinct red colour, and a light curve that fades slowly with ...

Luminous blue variable Luminous blue variables (LBVs) are rare, massive, evolved stars that show unpredictable and sometimes dramatic variations in their spectra and brightness. They are also known as S Doradus variables after S Doradus, one of the brightest stars of th ...

Wolf–Rayet star Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectroscopy, spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very ...

Supernova impostor Supernova impostors are stellar explosions that appear at first to be a supernova but do not destroy their progenitor stars. As such, they are a class of extra-powerful novae. They are also known as Type V supernovae, Eta Carinae analogs, and gi ...

Supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

Hypernova A hypernova is a very energetic supernova which is believed to result from an extreme core collapse scenario. In this case, a massive star (>30 solar masses) collapses to form a rotating black hole emitting twin astrophysical jets and surrounded b ...

Hertzsprung–Russell diagram The Hertzsprung–Russell diagram (abbreviated as H–R diagram, HR diagram or HRD) is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities and their stellar classifications or effective temp ...

Color–color diagram A color–color diagram is a means of comparing the colors of an astronomical object at different wavelengths. Astronomers typically observe at narrow bands around certain wavelengths, and objects observed will have different brightnesses in each ...

Protostar A protostar is a very young star that is still gathering mass from its parent molecular cloud. It is the earliest phase in the process of stellar evolution. For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. The p ...

s **

Molecular cloud A molecular cloud—sometimes called a stellar nursery if star formation is occurring within—is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, ...

*** H II region ** Bok globule ** Young stellar object ** Herbig–Haro object ** Hayashi track ** Hayashi limit ** Henyey track ** Orion variable *** T Tauri star *** FU Orionis star ** Herbig Ae/Be star, Herbig Ae/Be * Luminosity class ** Subdwarf star ** Dwarf star *** Blue dwarf (red-dwarf stage), Blue dwarf *** Red dwarf ** Subgiant ** Giant star *** Blue giant *** Red giant ** Bright giant ** Supergiant *** Blue supergiant *** Red supergiant *** Yellow supergiant ** Hypergiant *** Yellow hypergiant ** Blue straggler *

** O-type main-sequence star ** B-type main-sequence star ** A-type main-sequence star ** F-type main-sequence star ** G-type main-sequence star ** K-type main-sequence star ** M-type main-sequence star ** Be star ** OB star ** Subdwarf B star ** Late-type star ** Peculiar star *** Am star *** Ap and Bp stars **** Rapidly oscillating Ap star *** Barium star *** Carbon star *** CH star *** Extreme helium star *** Lambda Boötis star *** Lead star *** Mercury-manganese star *** S-type star *** Shell star *** Technetium star * Remnants ** White dwarf *** Black dwarf *** Helium planet ** Neutron star ***Pulsar *** Magnetar ** Stellar black hole ** Compact star *** Quark star *** Exotic star ** Stellar core: EF Eridani * Failed and theoretical stars ** Substellar object *** Brown dwarf **** Sub-brown dwarf *** Planetar (astronomy), Planetar ** Boson star ** Dark star (dark matter), Dark star ** Quasistar ** Thorne–Żytkow object ** Iron star * Stellar nucleosynthesis ** Alpha process ** Triple-alpha process ** Proton–proton chain reaction ** Helium flash ** CNO cycle ** Lithium burning ** Carbon-burning process ** Neon-burning process ** Oxygen-burning process ** Silicon-burning process ** S-process ** R-process ** Nova *** Nova remnant * Stellar structure **

*** Microturbulence *** Solar-like oscillations **

** Starspot **

** Stellar corona ** Stellar wind *** Stellar-wind bubble ** Asteroseismology ** Eddington luminosity ** Kelvin–Helmholtz mechanism * Properties ** Star designation ** Stellar dynamics ** Effective temperature ** Stellar kinematics ** Stellar magnetic field ** Magnitude (astronomy), Magnitude *** Absolute magnitude ** Solar mass ** Metallicity ** Stellar rotation ** UBV photometric system ** Variable star * Star systems ** Binary star *** Contact binary *** Common envelope ** Multiple star ** Accretion disc ** Planetary system ** Solar System, Earth's Solar System * Earth-centric observation of stars ** Pole star ** Circumpolar star ** Magnitude (astronomy), Magnitude *** Apparent magnitude *** Photographic magnitude *** color-color diagram ** Radial velocity **

** ** Photometric-standard star * Lists of stars ** List of proper names of stars ** List of Arabic star names ** Traditional Chinese star names ** List of most massive stars ** List of least massive stars ** List of largest known stars ** List of brightest stars *** Historical brightest stars ** List of most luminous stars ** List of nearest stars *** List of nearest bright stars ** List of exoplanetary host stars ** List of brown dwarfs ** List of planetary nebulae ** List of novae **

** List of supernova remnants ** List of supernova candidates ** Timeline of stellar astronomy

Variable stars

Variable star * Pulsating ** Cepheids and cepheid-like *** Cepheid variable *** Type II Cepheids *** RR Lyrae variable *** Delta Scuti variable *** SX Phoenicis variable ** Blue-white with early spectra *** Beta Cephei variable *** PV Telescopii variable ** Long period variable, Long Period and Semiregular ***

*** Semiregular variable *** Slow irregular variable ** Other *** RV Tauri variable *** Alpha Cygni variable *** Pulsating white dwarf * Eruptive ** Pre-main sequence star *** Herbig Ae/Be stars, Herbig Ae/Be *** Orion variable *** FU Orionis star ** Main Sequence *** Wolf-Rayet star *** Flare star ** Giants and supergiants ***

*** Gamma Cassiopeiae variable *** R Coronae Borealis variable ** Eruptive binary *** RS Canum Venaticorum variable ** Cataclysmic or explosive *** Cataclysmic variable star *** Dwarf nova *** Nova ***

*** Z Andromedae * Rotating ** Non-spherical *** Ellipsoidal ** Stellar spots *** FK Comae Berenices *** BY Draconis variable ** Magnetic fields *** Alpha² Canum Venaticorum variable *** SX Arietis *** Pulsar * Eclipsing binary ** Algol variable ** Beta Lyrae variable ** W Ursae Majoris variable

Supernovae

* Classes ** Type Ia supernova ** Type Ib and Ic supernovae ** Type II supernova, Type II (IIP and IIL) * Related ** Near-Earth supernova **

** Quark-nova ** Pulsar kicks * Structure ** Pair-instability supernova ** Supernova nucleosynthesis ** P-process ** R-process ** Gamma-ray burst ** Carbon detonation * Progenitors **

** Supergiant *** Blue supergiant *** Red supergiant *** Yellow supergiant ** Hypergiant *** Yellow hypergiant ** White dwarf * Remnants ** Supernova remnant ** Neutron star *** Pulsar *** Magnetar *** Stellar black hole ** Compact star ** Supergiant *** Quark star *** Exotic star * Discovery ** Guest star (astronomy), Guest star **

** Timeline of white dwarfs, neutron stars, and supernovae * Notable **

** List of supernova remnants ** List of supernova candidates ** List of most massive stars ** Supernovae in fiction ** SN 1054 ** Supergiant *** Crab Nebula ** SN 1572, Tycho's ** SN 1604, Kepler's ** SN 1987A ** SN 185 ** SN 1006 ** SN 2003fg ** Vela Supernova Remnant ** Supernova remnant G1.9+0.3, Remnant G1.9+0.3 ** SN 2007bi * Research ** Supernova Cosmology Project ** High-z Supernova Search Team ** Texas Supernova Search ** Nearby Supernova Factory ** Supernova Legacy Survey ** Supernova Early Warning System ** Monte Agliale Supernovae and Asteroid Survey ** Supernova/Acceleration Probe **

Black holes

Black hole * Types **Schwarzschild metric ** Rotating black hole ** Charged black hole ** Virtual black hole * Size **Micro black hole ** Extremal black hole (Black hole electron) ** Stellar black hole ** Intermediate-mass black hole ** Supermassive black hole ** Quasar *** Active galactic nucleus *** Blazar * Formation **

** Gravitational collapse ** Neutron star (Template:neutron star) ** Compact star *** Quark star *** Exotic star ** Tolman–Oppenheimer–Volkoff limit ** White dwarf (Template:white dwarf) **

(Template:supernovae) **

** Gamma-ray burst * Properties **Black hole thermodynamics ** Schwarzschild radius ** M–sigma relation ** Event horizon ** Quasi-periodic oscillation ** Photon sphere ** Ergosphere ** Hawking radiation ** Penrose process ** Bondi accretion ** Spaghettification ** Gravitational lens * Models **Gravitational singularity (Penrose–Hawking singularity theorems) ** Primordial black hole ** Gravastar ** Dark star (Newtonian mechanics), Dark star ** Dark energy star ** Black star (semiclassical gravity), Black star ** Magnetospheric eternally collapsing object ** Fuzzball (string theory), Fuzzball ** White hole ** Naked singularity ** Ring singularity ** Immirzi parameter ** Membrane paradigm ** Kugelblitz (astrophysics), Kugelblitz ** Wormhole ** Quasistar * Issues **No-hair theorem ** Black hole information paradox ** Cosmic censorship hypothesis ** Nonsingular black hole models ** Holographic principle ** Black hole complementarity * Metrics **Schwarzschild metric ** Kerr metric ** Reissner–Nordström metric, Reissner–Nordström ** Kerr–Newman metric, Kerr–Newman * Related **List of black holes ** Timeline of black hole physics ** Rossi X-ray Timing Explorer ** Hypercompact stellar system

Constellations

* Constellation * Constellation family

The 88 modern constellations

* Andromeda (constellation), Andromeda * Antlia * Apus * Aquarius (constellation), Aquarius * Aquila (constellation), Aquila * Ara (constellation), Ara * Aries (constellation), Aries * Auriga (constellation), Auriga * Boötes * Caelum * Camelopardalis * Cancer (constellation), Cancer * Canes Venatici * Canis Major * Canis Minor * Capricornus * Carina (constellation), Carina * Cassiopeia (constellation), Cassiopeia * Centaurus * Cepheus (constellation), Cepheus * Cetus * Chamaeleon * Circinus (constellation), Circinus * Columba (constellation), Columba * Coma Berenices * Corona Australis * Corona Borealis * Corvus (constellation), Corvus * Crater (constellation), Crater * Crux * Cygnus (constellation), Cygnus * Delphinus * Dorado * Draco (constellation), Draco * Equuleus * Eridanus (constellation), Eridanus * Fornax * Gemini (constellation), Gemini * Grus (constellation), Grus * Hercules (constellation), Hercules * Horologium (constellation), Horologium * Hydra (constellation), Hydra * Hydrus * Indus (constellation), Indus * Lacerta * Leo (constellation), Leo * Leo Minor * Lepus (constellation), Lepus * Libra (constellation), Libra * Lupus (constellation), Lupus * Lynx (constellation), Lynx * Lyra * Mensa (constellation), Mensa * Microscopium * Monoceros (constellation), Monoceros * Musca * Norma (constellation), Norma * Octans * Ophiuchus * Orion (constellation), Orion * Pavo (constellation), Pavo * Pegasus (constellation), Pegasus * Perseus (constellation), Perseus * Phoenix (constellation), Phoenix * Pictor * Pisces (constellation), Pisces * Piscis Austrinus * Puppis * Pyxis * Reticulum * Sagitta * Sagittarius (constellation), Sagittarius * Scorpius * Sculptor (constellation), Sculptor * Scutum (constellation), Scutum * Serpens * Sextans * Taurus (constellation), Taurus * Telescopium * Triangulum * Triangulum Australe * Tucana * Ursa Major * Ursa Minor * Vela (constellation), Vela * Virgo (constellation), Virgo * Volans * Vulpecula

Constellation history

= The 48 constellations listed by Ptolemy after 150 AD

= * Andromeda (constellation), Andromeda * Aquarius (constellation), Aquarius * Aquila (constellation), Aquila * Ara (constellation), Ara * Argo Navis * Aries (constellation), Aries * Auriga (constellation), Auriga * Boötes * Cancer (constellation), Cancer * Canis Major * Canis Minor * Capricornus * Cassiopeia (constellation), Cassiopeia * Centaurus * Cepheus (constellation), Cepheus * Cetus * Corona Australis * Corona Borealis * Corvus (constellation), Corvus * Crater (constellation), Crater * Cygnus (constellation), Cygnus * Delphinus * Draco (constellation), Draco * Equuleus * Eridanus (constellation), Eridanus * Gemini (constellation), Gemini * Hercules (constellation), Hercules * Hydra (constellation), Hydra * Leo (constellation), Leo * Lepus (constellation), Lepus * Libra (constellation), Libra * Lupus (constellation), Lupus * Lyra * Ophiuchus * Orion (constellation), Orion * Pegasus (constellation), Pegasus * Perseus (constellation), Perseus * Pisces (constellation), Pisces * Piscis Austrinus * Sagitta * Sagittarius (constellation), Sagittarius * Scorpius * Serpens * Taurus (constellation), Taurus * Triangulum * Ursa Major * Ursa Minor * Virgo (constellation), Virgo

= The 41 additional constellations added in the 16th and 17th centuries

= * ''Vespucci or Corsalius early 16c'': Crux * Triangulum Australe ▶ ''Vopel'' 1536: Coma Berenices ▶ ''Keyser & de Houtman'' 1596: Apus * Chamaeleon * Dorado * Grus (constellation), Grus * Hydrus * Indus (constellation), Indus * Musca * Pavo (constellation), Pavo * Phoenix (constellation), Phoenix * Tucana * Volans ▶ ''Plancius'' 1613: Camelopardalis * Columba (constellation), Columba * Monoceros (constellation), Monoceros ▶ ''Habrecht'' 1621: Reticulum ▶ ''Hevelius'' 1683: Canes Venatici * Lacerta * Leo Minor * Lynx (constellation), Lynx * Scutum (constellation), Scutum * Sextans * Vulpecula ▶ ''de Lacaille'' 1763: Antlia * Caelum * Carina (constellation), Carina * Circinus (constellation), Circinus * Fornax * Horologium (constellation), Horologium * Mensa (constellation), Mensa * Microscopium * Norma (constellation), Norma * Octans * Pictor * Puppis * Pyxis * Sculptor (constellation), Sculptor * Telescopium * Vela (constellation), Vela

= Obsolete constellations including Ptolemy's ''Argo Navis''

= Former constellations, Obsolete constellations including Ptolemy's ''Argo Navis'' Vulpecula#History, Anser * Antinous (constellation), Antinous * Argo Navis * Canes Venatici#History, Asterion * Cancer Minor (constellation), Cancer Minor * Cerberus (constellation), Cerberus * Canes Venatici#History, Chara * Custos Messium * Felis (constellation), Felis * Frederici Honores, Frederici Honores/Gloria Frederici * Gallus (constellation), Gallus * Globus Aerostaticus * Jordanus (constellation), Jordanus * Lochium Funis * Machina Electrica * Malus (constellation), Malus * Mons Maenalus * Musca Borealis * Noctua (constellation), Noctua * Officina Typographica * Polophylax * Psalterium Georgii, Psalterium Georgianum/Harpa Georgii * Quadrans Muralis * Ramus Pomifer * Robur Carolinum * Sceptrum Brandenburgicum * Sceptrum et Manus Iustitiae * Solarium (constellation), Solarium * Rangifer (constellation), Rangifer/Tarandus * Taurus Poniatovii * Telescopium Herschelii * Pisces (constellation)#Asterisms and subdivision, Testudo * River Tigris (constellation), Tigris * Triangulum Minus * Turdus Solitarius * Vespa (constellation), Vespa * Lyra (constellation)#Mythology, Vultur cadens * Aquila (constellation)#History, Vultur volans

Clusters and nebulae

* Interstellar matter * Nebula * Crab Nebula * H I region * H II region * Orion nebula *

* Pleiades

Galaxies

* Galaxy * Andromeda Galaxy * Magellanic Clouds * Quasar

Cosmology

* Big Bang * Cosmic microwave background * Cosmos * Dark matter * Cosmic distance ladder * Hubble constant * Olbers's paradox * Universe

Space exploration

: ''See: Outline of space exploration''

Organizations

Public sector space agencies

List of space agencies, Space agencies

=Africa

North Africa

* Algerian Space Agency * National Authority for Remote Sensing and Space Sciences * Egypt Remote Sensing Center * Royal Centre for Remote Sensing * National Remote Sensing Center

Sub-Saharan

* National Space Research and Development Agency * South African National Space Agency

=North America

= * Agencia Espacial Mexicana * Canadian Space Agency * NASA * United States Department of Defense ** National Reconnaissance Office ** United States Army Space and Missile Defense Command ** United States Space Command ** United States Space Force

=South America

= * Agencia Bolivariana para Actividades Espaciales * Brazilian Space Agency * Brazilian General Command for Aerospace Technology * Colombian Space Commission * Comisión Nacional de Actividades Espaciales * Comisión Nacional de Investigación y Desarrollo Aeroespacial * Instituto Tecnológico de Aeronáutica * Instituto Venezolano de Investigaciones Científicas * National Institute for Space Research

=Asia

East Asia

* China Aerospace Science and Technology Corporation (China Academy of Launch Vehicle Technology * China Academy of Space Technology * China Chang Feng * China Aerospace Science and Technology Corporation * Commission for Science, Technology and Industry for National Defense) * China National Space Administration * Japan Aerospace Exploration Agency (Institute of Space and Astronautical Science * National Aerospace Laboratory of Japan * National Space Development Agency of Japan) * National Institute of Information and Communications Technology * Institute for Unmanned Space Experiment Free Flyer * National Remote Sensing Center * Korean Committee of Space Technology * Korea Aerospace Research Institute * National Space Organization (Republic of China), National Space Organization

Southeast Asia

* National Institute of Aeronautics and Space * Malaysian Space Agency * Philippine Atmospheric, Geophysical and Astronomical Services Administration * Thai Ministry of Science and Technology's Space Agency * Space Technology Institute * Vietnam Space Commission

South Asia

* Space Research and Remote Sensing Organization * Department of Space ** Antrix Corporation ** Indian Institute of Space Science and Technology ** Indian Space Research Organisation ** National Atmospheric Research Laboratory ** New Space India Limited ** North-Eastern Space Applications Centre ** Physical Research Laboratory ** Semi-Conductor Laboratory * Space and Upper Atmosphere Research Commission

Southwest Asia

* Azerbaijan National Aerospace Agency * Iran Aviation Industries Organization * Iranian Space Agency * Israel Space Agency * National Committee for Space Research * TUBITAK Space Technologies Research Institute, TÜBİTAK UZAY

Central Asia

* KazCosmos * Kazakh Space Research Institute * Turkmenistan National Space Agency * UzbekCosmos

=Europe

= * Austrian Space Agency * Belarus Space Agency * Belgian Institute for Space Aeronomy * Bulgarian Space Agency * Czech Space Office * Danish National Space Center * esa European Cooperation for Space Standardization * European Space Agency * EUMETSAT * European Union Satellite Centre * CNES * German Aerospace Center * Institute for Space Applications and Remote Sensing * Hungarian Space Office * Space Ireland * Italian Space Agency * Space Science and Technology Institute * Luxinnovation * Netherlands Institute for Space Research * Norwegian Space Centre * Space Research Centre * Portuguese Space Company * Romanian Space Agency * Russian Federal Space Agency * Russian Space Research Institute * Russian Space Forces * Soviet space program * Instituto Nacional de Técnica Aeroespacial * Swedish National Space Board * Swiss Space Office * UK Space Agency * State Space Agency of Ukraine

=Oceania

= * Commonwealth Scientific and Industrial Research Organisation

=World

= * Asia-Pacific Space Cooperation Organization * Consultative Committee for Space Data Systems * Committee on Space Research * International Academy of Astronautics * International Telecommunications Satellite Organization * Intercosmos * Intersputnik * Pan-Arab Space Agency * United Nations ** United Nations Committee on the Peaceful Uses of Outer Space ** United Nations Office for Outer Space Affairs Preceded by the Soviet space program

Books and publications

* ''Almagest'' * ''Astronomia nova, Astronomia Nova'' * ''Astronomical Journal'' * ''Astrophysical Journal'' * ''Durchmusterung, BD Catalogue'' * ''De Revolutionibus'' * ''Henry Draper Catalogue'' * ''Messier Catalogue'' * ''New General Catalogue'' * ''Philosophiæ Naturalis Principia Mathematica, Principia''

Astronomers

* Aryabhata * Walter Baade * Friedrich Bessel *

* Annie Jump Cannon * Alvan Clark * Nicholas Copernicus *

* George Ellery Hale * William Herschel * Edwin Hubble * Jacobus Kapteyn * Johannes Kepler * Gerard Kuiper * Joseph-Louis Lagrange * Pierre-Simon Laplace * Henrietta Leavitt * Isaac Newton * Edward C. Pickering * Ptolemy * Henry Norris Russell * Harlow Shapley

References

External links

Astronomy Guide
For reviews on astronomy products, how-to's and current events.
Astronomy Net
Resources, forums (from 1995), articles on Astronomy.
International Year of Astronomy 2009
IYA2009 Main website

from the American Institute of Physics
Astronomy Picture of the DaySouthern Hemisphere Astronomy''Sky & Telescope''
publishers
''Astronomy'' MagazineLatest astronomy news in 11 languagesUniverse Today
for astronomy and space-related news
Celestia Motherlode
Educational site for Astronomical journeys through space
Search Engine for AstronomyHubblesite.org – home of NASA's Hubble Space Telescope''Astronomy – A History'' – G. Forbes – 1909 (eLibrary Project – eLib Text)
* (historical)
Prof. Sir Harry Kroto, NL
Astrophysical Chemistry Lecture Series. 8 Freeview Lectures provided by the Vega Science Trust.
Core books
an
core journals
in Astronomy, from the Smithsonian/NASA Astrophysics Data System {{DEFAULTSORT:Astronomy Outlines of natural sciences, Astronomy Astronomy, *Outline Astronomy-related lists, Outlines of sciences Outlines, Astronomy