• Accretion disk: the gas and dust surrounding a star or blackhole.
• Antimatter: matter composed of particles of the opposite change of ordinary matter. While protons have a negative charge, anti-protons have positive charges.
• Asteroid: a small celestial body in orbit around a sun. An asteroid is larger than a meteoroid but smaller than a planet.
• Binary: a system composed of two stars that revolve around a common center of gravity.
• Black hole: the collapsing core of a massive star. Its’ gravitational pull is so strong not even light can escape and it will continue to collapse until all matter is crushed out of existence into a singularity.
• Bolide: an extremely bright meteor producing a sonic boom.
• Catena: a series of craters
• Chondrite: a meteorite that contains chondrules.
• Chondrules: small, glassy spheres commonly found in meteorites.
• Chromosphere: the Sun’s atmosphere just above the surface
• Circumstellar disk: a ring-shaped accumulation of gas, dust, and debris in orbit around a star.
• Coma: an area of dust and gas surrounding the nucleus of a comet.
• Comet: a collection of ice and rock in orbit around the sun.
• Corona: the outer part of the Sun’s atmosphere.
• Crater: a depression formed by the impact of an asteroid or meteoroid.
• Dark matter: matter in the universe which cannot be seen but can be detected by gravitational effects.
• Dwarf planet: a celestial body orbiting a sun that is massive enough to be rounded by its own gravity but has not achieved hydrostatic equilibrium. Smaller than a planet but larger than a satellite.
• Event horizon: the boundary surrounding a black hole that marks the point at which nothing can escape its’ gravitational pull.
• Faculae: bright patches visible on the surface of the sun.
• Flare star: a faint red star that changes in brightness due to explosions on its’ surface.
• Galactic nucleus: the concentration of stars and gas at the innermost region of a galaxy.
• Galaxy: a large grouping of stars.
• Galilean moons: Jupiter’s four largest moons: Io, Europa, Callisto, & Ganymede. They were independently discovered by Galileo Galilei and Simon Marius.
• Giant Molecular Cloud (GMC): a massive cloud of hydrogen gas that can produce stars.
• Globular cluster: a grouping of thousands of nearby stars.
• Heliopause: the boundary in space where the solar wind meets the interstellar medium.
• Heliosphere: The space within the boundary of the heliopause that contains the Sun and Solar System.
• Interplanetary magnetic field: the magnetic field carried with the solar wind.
• Interstellar medium: the gas and dust between stars.
• Ionosphere: a region of charged particles in the upper atmosphere.
• Kirkwood gaps: spaces in a main belt of asteroids where few or no asteroids are present.
• Kuiper Belt: a ring of icy objects outside the orbit of Neptune.
• Lagrange point: a point in space relative to two orbiting bodies where the gravitational forces can hold an object in that same relative position. Lagrange points are widely thought of as being perfect locations for space stations and are often the sites of asteroid accumulation.
• Magnetosphere: the region around a planet most effected by its’ magnetic field.
• Main belt: the region between Mars and Jupiter where most of the solar system’s asteroids are located.
• Mare: meaning ‘sea,’ a term used to describe a large flat area or plain. The moon has many such flat maria.
• Meteor: rock or dust that burns away in the atmosphere. Also known as a shooting star.
• Meteorite: a meteor that reaches the Earth’s surface.
• Meteoroid: a small rock in orbit. Smaller than an asteroid.
• Nebula: a cloud of dust and gas.
• Neutron star: the compressed core of an exploded star with a strong gravitational field.
• Nova: a star that increases in brightness before returning to its original state.
• Oort cloud: a shell of comets thought to exist at the outer edge of our solar system.
• Planemo: a planet or planetary body tat does not orbit a star but instead wanders though space.
• Planitia: a low plain.
• Planum: a high plain or plateau.
• Protostar: a dense region of molecular clouds where stars form.
• Pulsar: a spinning neutron star that emits energy along its gravitational axis.
• Quasar: some of the oldest and farthest objects in the known universe, these are unusually bright objects that may be a nuclei of ancient galaxies.
• Radio galaxy: a galaxy that gives off massive amounts of energy in the form of radio waves.
• Red giant: a star in a later stage in it’ evolution where the star grows to ~50 times its’ usual size and gives off a red appearance.
• Satellite: either a natural (such as a moon) or artificial body in orbit around a planet.
• Singularity: the center of a black hole where no solid object can survive.
• Solar wind (also known as stellar wind): the flow of charged particles that move from the sun out into the solar system.
• Sunspot: an area on the sun’s surface that is cooler than the surrounding areas and often appears dark in color.
• Supergiant: a star in a stage of its lifecycle where the star swells to ~500 times its’ usual size.
• Terminator: the boundary between the light and dark sides of a planet or other body.
• Trojan: an object orbiting in the Lagrange point of another, larger object.
• Van Allen Belts: zones of radiation that surround Earth.
• White dwarf: a small white star.

How many planets exist in your world? How many moons?