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

A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. Planets grow in this disk by the gradual accumulation of material driven by gravity, a process called accretion. The Solar System has at least eight planets: the terrestrial planets Mercury, Venus, Earth, and Mars, and the giant planets Jupiter, Saturn, Uranus, and Neptune.

What type of thing are planets?

Planets can be described as all of the following:

• Astronomical objects
  • Gravitationally rounded objects

Types of planets

Planet

• Planet types by location
  • Planet of the Solar System
    • Inferior planet
    • Superior planet
    • Inner planet
    • Outer planet
  • Exoplanet
• Planet types by make-up
  • Terrestrial planet
  • Giant planet
    • Gas giant
    • Ice giant

Other

• Double planet – Two planetary mass objects orbiting each other
• Mesoplanet – A planet smaller than Mercury but larger than Ceres
• Minor planet – A celestial body smaller than a planet
• Planetary-mass object –

Planetary characteristics

Planetary attributes

• Orbit –
  • Heliocentric orbit – orbit around the barycenter of the Solar System, which is usually located within or very near the surface of the Sun. All planets, comets, and asteroids in the Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet.
• Planetary habitability – The measure of a planet's ability to sustain life.

Planetary features

Specific planets

• Lists of planets – A list of lists of planets sorted by diverse attributes
  • List of exoplanets

Planets of the solar system

1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune

Exoplanets

History of planets

History of planet observation

• History of Mars observation

Geological history of planets

• Geological history of Earth

• Geological history of Mars

Planetary science

Planetary science – scientific study of planets

Planets in culture

• Planets in astrology
• Planetary mnemonic – A phrase used to remember the names of the planets
• Planets in science fiction

Planet-related organizations

• Division for Planetary Sciences (DPS) of the American Astronomical Society
• American Geophysical Union
• Meteoritical Society
• Europlanet

Conferences

• Lunar and Planetary Science Conference (LPSC) – organized by the Lunar and Planetary Institute in Houston. Held annually since 1970, occurs in March.
• Division for Planetary Sciences (DPS) – meeting held annually since 1970 at a different location each year, predominantly within the mainland US. Occurs around October.
• American Geophysical Union (AGU) – annual Fall meeting in December in San Francisco.
• American Geophysical Union (AGU) – Joint Assembly (co-sponsored with other societies) in April–May, in various locations around the world.
• Meteoritical Society – annual meeting, held during the Northern Hemisphere summer, generally alternating between North America and Europe.
• European Planetary Science Congress (EPSC) – held annually around September at a location within Europe.

National space agencies

• Ames (NASA)
• Canadian Space Agency (CSA) –
• China National Space Administration (CNSA) – in China (People's Republic of China).
• Centre national d'études spatiales – French National Centre of Space Research
• Deutsches Zentrum für Luft- und Raumfahrt e.V. (German: abbreviated DLR) – the German Aerospace Center
• European Space Agency (ESA) –
• Russian Federal Space Agency –
• GSFC (NASA) –
• Indian Space Research Organisation (ISRO) –
• Israel Space Agency (ISA) –
• Italian Space Agency –
• Japan Aerospace Exploration Agency (JAXA) –
• JPL (NASA) –
• NASA – has a considerable number of research groups, including the JPL, GSFC, Ames.
• National Space Organization – in Taiwan (Republic of China).
• UK Space Agency (UKSA) –

Research institutions

• The Australian National University's Planetary Science Institute
• Brown University Planetary Geosciences Group
• Caltech's Division of Geological and Planetary Sciences
• Cornell University's Space and Planetary Science
• Florida Institute of Technology's Department of Physics and Space Sciences
• Johns Hopkins University Applied Physics Laboratory [1]
• Lunar and Planetary Institute
• Max Planck Institute for Solar System Research's Department Planets and Comets
• MIT Dept. of Earth, Atmospheric and Planetary Sciences
• Open University Planetary and Space Sciences Research Institute
• Planetary Science Institute
• Stony Brook University's Geosciences Department and soon to open Center for Planetary Exploration
• UCL/Birkbeck's Centre for Planetary Sciences
• UCLA Department of Earth, Planetary, and Space Sciences
• University of Arizona's Lunar and Planetary Lab
• University of Arkansas's Center for Space and Planetary Sciences
• University of California Santa Cruz's Department of Earth & Planetary Sciences
• University of Hawaii's Hawaii Institute of Geophysics and Planetology
• University of Copenhagen's Center for Planetary Research
• University of Central Florida Planetary Sciences Group
• University of British Columbia Institute for Planetary Science
• University of Western Ontario's Centre for Planetary Science and Exploration
• University of Tennessee Department of Earth and Planetary Sciences
• University of Colorado's Department of Astrophysical and Planetary Sciences
• INAF– Istituto di Astrofisica e Planetologia Spaziali [2]

Planet-related publications

Planetary science journals

• Earth and Planetary Science Letters
• Earth, Moon, and Planets
• Geochimica et Cosmochimica Acta
• Icarus
• Journal of Geophysical Research—Planets
• Meteoritics and Planetary Science
• Planetary and Space Science

Persons influential in planetary science