|The proper names of astronomical bodies are capitalized; generic terms are usually lowercased:
|the Virgo cluster; Local Group; our local supercluster
the Milky Way, the Milky Way galaxy; galaxy NGC 7252; Andromeda galaxy, or M31
supernova 1981b, or SN 1981b; supernovae, quasar 3C 273
constellation Orion; Cassiopeia (Lady in the Chair); the Southern Cross; Ursa Major (Great Bear)
the Horsehead Nebula; the Great Spiral Nebula of Andromeda, the nebula
Van Allen belt, Kuiper belt
Large and Small Magellanic Clouds, but Oort cloud
Polaris, the North Star; Barnard's star; Eta Carinae; Mu Arae; Gliese 236; 55 Cancri
Halley's comet or comet Halley
the asteroid Geographos, Allende meteorite
Great Red Spot, Planet X
aurora borealis, aurora australis
big bang, black hole,
the solar system
|Objects are sometimes designated by a catalog number or abbreviation and
Abell 2218, or A 2218 New General Catalogue 6165, or NGC
Messier 31, or M31 Lings 1251 or L1251.
The names sun and moon are lowercase. Earth is
capitalized as the name of our planet whether used in context with other
planet names or not. Do not capitalize when meaning dirt or the
terrestrial part of our planet compared with sea and sky and in
compounds such as earthquake, earth-shattering, earthbound.
See also MOON TERMS, SPACE TERMS, sun.