Celestial terminology is a list of universal terms agreed on by collaborations of many empires as to prevent confusion.

Planet terminology[edit | edit source]

A planet refers to a celestial body which usually orbits a star, significantly larger than an asteroid.

Types of worlds[edit | edit source]

  • Ammonia - An ammonia world is covered in oceans of either ammonia of water-ammonia mixture.
  • Brown dwarf - A large body bigger than a gas giant, but smaller than a star. Many are between 75 and 80 Jupiter masses.
  • Crater - A crater world is one with no atmosphere and consists of a rocky surface. It is subject to be pelted with asteroids and meteors. An example is the planet Mercury.
    • Carbon - A type of crater world with layers of graphic and diamond on the surface.
  • Crystal - A crystal world is usually made of ice or other materials.
  • Desert - A world that was once flourishing with life, but a cataclysmic event destroyed almost all life. Most of the soil has eroded into sand. An example is Mars.
  • Gas giant - A large planet consisting of a solid core and a large atmosphere. It has many moons and often times, some rings. Gas giants normally form further from its star. An example is Jupiter.
    • Hot Jupiter - A gas giant that orbits close to its star. These types of worlds are likely to be extrasolar captures. An example is 51 Pegasi b.
    • Chthonian - A former gas giant that has been entirely stripped of its atmosphere. It is found orbiting close to a star.
    • Gas dwarf - A gas planet with a mass substantially lower than the planet Neptune. A possible example is Kepler-11f.
  • Greenhouse - Greenhouse worlds are terrestrial worlds with a thick atmosphere that traps greenhouses gases, making it generally inhospitable on the surface. An example is Venus.
  • Ice dwarf - A small planetoid often found at the edges of a star system.
  • Methane - Methane worlds are farther from their parent star than worlds covered in liquid water. Despite this, a well developed methane planet can support not only stable liquid oceans of hydrocarbon, but theoretically methane-based life. An example is Saturn's moon, Titan.
  • Moon - A smaller world that orbits a larger one. Gaea's moon Selene is a typical example.
  • Ocean - A world consisting of a single ocean. A possible example is Kepler 22b.
  • Pulsar planet - An uncommon type of planet which orbits a pulsar. They form from the remains of a supernova.
  • Rogue - A rogue planet has no parent star. Most typically, these are gas giants that had migrated too far outward.
  • Snowball - A type of planet is either early in formation or is currently in a planetwide Ice Age. It may have either snow or ice. An example is Jupiter's moon, Europa.
  • Vesperian - A planet that has become tidally locked to its star causing it to form two distinct halves on its surface. An example is Gliese 581 b.
  • Volcanic - A planet wrecked with volcanism. If the planet is close enough to its star, it may even be covered entirely in lava. An example is Jupiter's moon, Io.

Specific terms[edit | edit source]

The following terms describe more variation of the types of worlds listed above.Earth-like - A planet with a similar environment and atmosphere to Earth. Humans would be able to survive on these worlds with no pressure suits or breathing masks.

  • Super-Earth - A terrestrial planet at least 1.5 times the size of Earth.
  • Terraforming - Reshaping a planet by artificially altering its atmospheric conditions to make it habitable.

Star terminology[edit | edit source]

Star types[edit | edit source]

The stellar classes F,G,K and M are capable of forming habitable worlds. Atmospheric conditions will make stars appear different colors, and their color will also have effects on flora. The color of the stars are determined by the wavelengths they emit combined with luminosity, though in space, it may or may not actually appear that color. Dim, cooler stars will appear red while brighter, hotter stars will appear blue.

  • Class O - A very rare giant blue star. They cannot support habitable worlds.
  • Class B - A blue star larger and more luminous than a Class B star. They cannot support habitable worlds.
  • Class A - A moderately large blue star. Class A stars cannot support habitable worlds.
  • Class F - A yellow-white star that emits plenty of UV rays. Class F is the hottest type of star that can potentially form habitable worlds, though early in formation, they are extremely volatile.
  • Class G - Yellow stars much like Sol.
  • Class K - These are orange stars slightly smaller than Class G stars, yet are very similar.
  • Class M - While this star varies in size, most are red dwarves. Red dwarves can last at least a trillion years, and worlds within this star's life zone or closer will be tidally locked. Red dwarves are also flare stars and will regularly output lethal rays of radiation.

Star sizes[edit | edit source]

  • Giant - A large red star; Usually a Yellow Main Sequence in its dying stage.
  • Dwarf - A standard main sequence star
  • Supergiant - A star larger than a giant
  • Hypergiant - An enormous star around the size of VY Canis Majoris.

Types of Star Systems[edit | edit source]

  • Single - A star system with only one star at its center. Single star systems are the most common.
  • Binary - A star system containing two stars that orbit around one another. They are relatively common throughout the universe, especially among early forming systems. Worlds can orbit either around one star or both.
  • Trinary - Three stars within the same system. Usually, it will appear binary, but a third, smaller star will be found orbiting the system's edges similar to the Alpha Centauri system.
  • Quaternary - A system with four stars. Usually, they are arranged as twin sets of binary stars.
  • Quinternary - A system with five stars.

Other[edit | edit source]

  • Supernova- A supernova is the event when massive stars die. Massive stars, when out of hydrogen, begin to duse helium, and so on, until they are left with iron, which releases no energy when fused. The star, now without the explosive energy of fusion to keep its mass from collapsing, begins to buckle in on itself. There comes a point where the star can collapse no further, and rebounds outward incredibly fast, exploding with more energy than most can imagine. Supernovae leave behind nebulae, the remains of the star, and sometimes neutron stars, pulsars, and, rarely, black holes. While spectacular to watch from a distance, proximity to a supernovae insures instant death by radiation, if not nuclear inferno.
  • White Dwarf - A small white star with a blue tinge; the end product of smaller stars like Yellow Main Sequences and Red Dwarves. The outer shells of the star simply fade away to space, leaving behind the still brightly glowing core. The core is no longer producing energy, and will eventually, after millions of years, fade to a black dwarf.
  • Black Dwarf - The final resting place of many stars; A black dwarf is an empty husk, the burnt out core of a dead star. The dwarf will eventually fall apart and drift into space, but not for some time. There has yet to be a single Black Dwarf encountered by any record in the history of spacefaring civilization, and some believe that they are, in fact, still only theoretical. that the Universe is still too young for there to be Black Dwarves. However, most astronomers agree that entropy will take its toll one day, and Black Dwarves will come to be more and more common.
  • Neutron star - A dead star which is the result of the death of a start massive enough to go supernova, but too small to become a black hole. The mass of the star actually causes the protons and electrons to fuse into neutrons, ergo the name. Neutron stars are renowned for their electromagnetic radiation and dangerous gravity wells.
    • Pulsar - A neutron star that is abnormally large. Pulsars have magnetic poles, like an iron-cored planet, but the poles are far more massive and unstable, and shift at regular intervals; 'North' is variable on a pulsar. When they shift, the poles cause massive levels of high-end (UV, X-ray, and Gamma Waves, usually) radiation in a single direction. If an instrument picks up these waves of radiation, it will read it as a pulse of energy, ergo the name. Pulsars are renowned for their capacity to sterilize worlds (Gamma Wave Bursts capable of planetary sterilization are commonly birthed at pulsars) and incredibly hazardous radiations, which are both lethal and annoying for those affected by the electromagnetic interference.
  • Black Hole- A supermassive star that has gone supernova and collapsed in on itself, causing all of it's mass to condense into its center. The mass of a black hole is so great that not even light can escape it. Black holes form when a star goes supernova. A black hole is not necessarily considered a star anymore.
    • Quasar - A black hole or possibly multiple black holes that have sucked in enough mass (likely other black holes) to expand to a size so massive that entire galaxies orbit around them. A quasar is theorized to be located at the center of the Milky Way and every elliptical galaxy.
    • Blazar - A quazar that has achieved the next phase of black holes. Blazars are supermassive black holes that emit unbelievably gargantuan jets of plasma and gamma radiation on either side of its planar shape. Blazar's are so massive, that it is theoretically possible that multiple galaxies could orbit them. A running theory for the birth of a Blazar is that they can be made when two galaxies collide.
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