Outline of astronomy

Last updated October 26, 2025

Mauna Kea in Hawaii is one of the world's premier observatory sites. Pictured is the W. M. Keck Observatory, an optical interferometer. KeckObservatory.jpg — Mauna Kea in Hawaii is one of the world's premier observatory sites. Pictured is the W. M. Keck Observatory, an optical interferometer.

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

Astronomy – studies the universe beyond Earth, including its formation and development, and the evolution, physics, chemistry, meteorology, and motion of celestial objects (such as galaxies, planets, etc.) and phenomena that originate outside the atmosphere of Earth (such as the cosmic background radiation). Astronomy also intersects with biology, as astrobiology, studying potential life throughout the universe.

Nature of astronomy

Astronomy can be described as all the following:

An academic discipline: one with academic departments, curricula and degrees; national and international societies; and specialized journals.
A scientific field (a branch of science) – widely recognized category of specialized expertise within science, and typically embodies it
- A natural science – one that seeks to elucidate the rules that govern the natural world using empirical and scientific methods.
  - A branch or field of space science
A hobby or part-time pursuit for the satisfaction of personal curiosity or appreciation of beauty, the latter especially including astrophotography.

Branches

Astrobiology – studies the advent and evolution of biological systems in the universe.
Astrophysics – branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior.^[1]^[2] Among the objects studied are galaxies, stars, planets, exoplanets, the interstellar medium and the cosmic microwave background; and the properties examined include luminosity, density, temperature, and chemical composition. The subdisciplines of theoretical astrophysics are:
- Compact objects – this subdiscipline studies very dense matter in white dwarfs and neutron stars and their effects on environments including accretion.
- Physical cosmology – origin and evolution of the universe as a whole. The study of cosmology is theoretical astrophysics at its largest scale.
- Quantum cosmology - the study of cosmology through the use of quantum field theory to explain phenomena general relativity cannot due to limitations in its framework.
- Computational astrophysics – The study of astrophysics using computational methods and tools to develop computational models.
- Galactic astronomy – 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, supernovae, gamma-ray bursts, quasars, and shocks.
- Interstellar astrophysics – study of the interstellar medium, intergalactic medium and dust.
- Extragalactic astronomy – study of objects (mainly galaxies) outside our Galaxy, including galaxy formation and evolution.
- Stellar astronomy – concerned with Star formation, physical properties, main sequence life span, variability, stellar evolution and extinction.
- Plasma astrophysics – studies properties of plasma in outer space.
- Relativistic astrophysics – studies effects of special relativity and general relativity in astrophysical contexts including gravitational waves, gravitational lensing and black holes.
- Solar physics – Sun and its interaction with the remainder of the Solar System and interstellar space.
Planetary Science – study of planets, moons, and planetary systems.
- Atmospheric science – study of atmospheres and weather.
- Exoplanetology – various planets outside of the Solar System
- Planetary formation – formation of planets and moons in the context of the formation and evolution of the Solar System.
- Planetary rings – dynamics, stability, and composition of planetary rings
- Magnetospheres – magnetic fields of planets and moons
- Planetary surfaces – surface geology of planets and moons
- Planetary interiors – interior composition of planets and moons
- Small Solar System bodies – smallest bodies, including asteroids, comets, Kuiper belt objects, and dust.
Astronomy divided by general technique used for astronomical research:
- Astrometry – study of the position of objects in the sky and their changes of position. Defines the system of coordinates used and the kinematics of objects in our Galaxy.
- Observational astronomy – practice of observing celestial objects by using telescopes and other astronomical apparatus. It is concerned with recording data. The subdisciplines of observational astronomy are generally made by the specifications of the detectors, specifically the ranges of wavelengths observed:
  - Radio astronomy – Above 300 μm
  - Submillimetre astronomy – 200 μm to 1 mm
  - Infrared astronomy – 0.7–350 μm
  - Optical astronomy – 380–750 nm
  - Ultraviolet astronomy – 10–320 nm
  - X-ray astronomy – 0.01–10 nm
  - Gamma-ray astronomy – Below 0.01 nm
  - Cosmic ray astronomy – Cosmic rays, including plasma
  - Neutrino astronomy – Neutrinos
  - Dust astronomy – Cosmic dust
  - Gravitational wave astronomy – Gravitons
- Photometry – study of how bright celestial objects are when passed through different filters
- Spectroscopy – study of the spectra of astronomical objects
Other disciplines that may be considered part of astronomy:
- Archaeoastronomy
- Astrochemistry

History

History of astronomy

History of the Center of the Universe
- Geocentric model
- Heliocentrism
  - Copernican heliocentrism
  - Tychonic system
Archaeoastronomy
- Archaeoastronomy and Vedic chronology
Pretelescopic astronomy
- Babylonian astronomy
- Chinese astronomy
- Egyptian astronomy
- Greek astronomy
- Hebrew astronomy
- Indian astronomy
- Islamic astronomy
- Russian astronomy
- Astronomy in the Middle Ages
  - Science in Medieval Western Europe
  - Astronomy in medieval Islam
History of astronomy in the Renaissance
- Scientific developments during the Scientific Revolution
  - Patronage in astronomy
  - Copernican Revolution
    - Copernican heliocentrism
    - Nicolaus Copernicus
      - On the Revolutions of the Heavenly Spheres
    - Tycho Brahe
      - Tychonic system
    - Galileo Galilei
      - Dialogue Concerning the Two Chief World Systems defense of the heliocentric system written by Galileo, which led to his trial and house arrest by the Inquisition.
  - Invention of the telescope
    - History of visible-light astronomy
History of astronomy in the Age of Reflection
Radio astronomy § History of radio astronomy
History of X-ray astronomy
History of infrared astronomy
History of gamma-ray astronomy
History of supernova observation
- List of supernovae

Basic astronomical phenomena

Astronomical objects

Astronomical object

Solar System

Planets

Planet
- Features
  - Natural satellites (moons)
  - Planetary rings
Planets of the Solar System
Dwarf planets of the Solar System

Exoplanets

Exoplanet (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 – exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants.
- Mini-Neptune – 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 – an exoplanet more massive than Jupiter.
- Sub-Earth – an exoplanet "substantially less massive" than Earth and Venus.
- Circumbinary planet – an exoplanet that orbits two stars.
- Hot Jupiter – 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 Sun) at 5.2 AU (780×106 km), causing low surface temperatures.
- Hot Neptune – 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 – a planet that orbits a pulsar or a rapidly rotating neutron star.
- Rogue planet (also known as an interstellar planet) – a planetary-mass object that orbits the galaxy directly.

Stars and stellar objects

Fixed stars

Stars

Constellations

The 88 modern constellations

Constellation history

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
Hydrus
Indus
Musca
Pavo
Phoenix
Tucana
Volans ▶ Plancius 1613: Camelopardalis
Columba
Monoceros ▶ Habrecht 1621: Reticulum ▶ Hevelius 1683: Canes Venatici
Lacerta
Leo Minor
Lynx
Scutum
Sextans
Vulpecula ▶ de Lacaille 1763: Antlia
Caelum
Carina
Circinus
Fornax
Horologium
Mensa
Microscopium
Norma
Octans
Pictor
Puppis
Pyxis
Sculptor
Telescopium
Vela

Clusters and nebulae

Galaxies

Cosmology

Space exploration

See: Outline of space exploration

Organizations

Public sector space agencies

Space agencies

Africa

North Africa

Sub-Saharan

North America

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

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

Southwest Asia

Central Asia

KazCosmos
Kazakh Space Research Institute ‹The template Smallsup is being considered for deletion.› ¹
Turkmenistan National Space Agency ‹The template Smallsup is being considered for deletion.› ¹
UzbekCosmos ‹The template Smallsup is being considered for deletion.› ¹

Europe

Austrian Space Agency
Belarus Space Agency ‹The template Smallsup is being considered for deletion.› ¹
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 ‹The template Smallsup is being considered for deletion.› ¹
Luxinnovation
Netherlands Institute for Space Research
Norwegian Space Centre
Space Research Centre
Portuguese Space Company
Romanian Space Agency
Russian Federal Space Agency ‹The template Smallsup is being considered for deletion.› ¹
Russian Space Research Institute ‹The template Smallsup is being considered for deletion.› ¹
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 ‹The template Smallsup is being considered for deletion.› ¹

Oceania

Commonwealth Scientific and Industrial Research Organisation

World

‹The template Smallsup is being considered for deletion.› ¹ Preceded by the Soviet space program

Books and publications

References

↑ "astrophysics". Merriam-Webster, Incorporated. Retrieved 2011-05-22.
↑ "Stern kaufen" . Retrieved 15 September 2012.

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
Cosmic Journey: A History of Scientific Cosmology from the American Institute of Physics
Astronomy Picture of the Day
Southern Hemisphere Astronomy
Sky & Telescope publishers
Astronomy Magazine
Latest astronomy news in 11 languages
Universe Today for astronomy and space-related news
Celestia Motherlode Educational site for Astronomical journeys through space
Search Engine for Astronomy
Hubblesite.org – home of NASA's Hubble Space Telescope Archived 2019-05-10 at the Wayback Machine
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 and core journals in Astronomy, from the Smithsonian/NASA Astrophysics Data System

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[1] "astrophysics". Merriam-Webster, Incorporated. Retrieved 2011-05-22.

[2] "Stern kaufen" . Retrieved 15 September 2012.

[1]

[2]

v t e Stellar systems
Bound	Galaxy Dwarf galaxy Star cluster Hypercompact stellar system Globular cluster Dark globular cluster Open cluster List of most massive star clusters List of largest star clusters Hypercompact stellar system Star system Binary star Planetary system
Unbound	Stellar stream Stellar association Moving group Runaway star Hypervelocity star
Visual grouping	Double star Multiple star Star cloud Asterism Constellation
Category:Star systems

v t e Galaxies
Morphology	Disc Thick disk Thin disk Lenticular barred unbarred Spiral anemic barred flocculent grand design intermediate Magellanic unbarred Dwarf galaxy elliptical irregular spheroidal spiral Elliptical galaxy cD Irregular barred Peculiar Ring Polar
Structure	Active galactic nucleus Bar Bulge Central massive object Galactic Center Dark matter halo Disc Disc galaxy Halo corona Galactic plane Galactic ridge Interstellar medium Protogalaxy Galaxy filament Spiral arm Supermassive black hole Ultramassive
Active nuclei	Blazar BL Lacertae object LINER Little Red Dots Markarian Quasar Radio X-shaped DRAGN Relativistic jet Seyfert
Energetic galaxies	Lyman-alpha emitter Lyman-break Luminous infrared ULIRG HLIRG ELIRG Starburst blue compact dwarf blueberry pea faint blue Luminous infrared galaxy Hot dust-obscured Green bean galaxy Hanny's Voorwerp Wolf-Rayet galaxy
Low activity	Low surface brightness Ultra diffuse Dark galaxy Red nugget Blue Nugget Dead disk
Interaction	Binary galaxy Field Galactic tide Groups and clusters group cluster Brightest cluster galaxy fossil group Interacting merger collision cannibalism Jellyfish Satellite Stellar stream Superclusters Walls Voids and supervoids void galaxy
Lists	Galaxies Galaxies named after people Largest Nearest Polar-ring Ring Spiral Groups and clusters Large quasar groups Quasars List of the most distant astronomical objects Starburst galaxies Superclusters Voids
Related	Extragalactic astronomy Galactic astronomy Galactic coordinate system Galactic habitable zone Galactic magnetic fields Galactic orientation Galactic quadrant Galaxy color–magnitude diagram Galaxy formation and evolution Galaxy rotation curve Gravitational lens Gravitational microlensing Illustris project Intergalactic dust Intergalactic stars Intergalactic travel Population III stars Galaxy X (galaxy)
Category Portal