Outline of astronomy


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 intersect with biology, as astrobiology, studying potential life throughout the universe.

Nature of astronomy

Astronomy can be described as all the following:

Branches of astronomy

History of astronomy

Basic astronomical phenomena

Astronomical objects

Astronomical object

Solar System

The SunMercuryVenusThe MoonEarthMarsPhobos and DeimosCeresThe main asteroid beltJupiterMoons of JupiterRings of JupiterSaturnMoons of SaturnRings of SaturnUranusMoons of UranusRings of UranusNeptuneMoons of NeptuneRings of NeptunePlutoMoons of PlutoHaumeaMoons of HaumeaMakemakeS/2015 (136472) 1The Kuiper BeltErisDysnomiaThe Scattered DiscThe Hills CloudThe Oort CloudThe Sun, the planets, their moons, and several trans-Neptunian objects



Small Solar System bodies


  • 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


Variable stars


Black holes

Artist's representation of a black hole.


The 88 modern constellations

Constellation history

The 48 constellations listed by Ptolemy after 150 AD
The 41 additional constellations added in the 16th and 17th centuries
Obsolete constellations including Ptolemy's Argo Navis

Clusters and nebulae



Space exploration

See: Outline of space exploration


Public sector space agencies

Space agencies

North Africa
North America
South America
East Asia
Southeast Asia
South Asia
Southwest Asia
Central Asia

1 Preceded by the Soviet space program

Books and publications


See also


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

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
  • 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