The Basics
Any of the large celestial bodies that revolve around the Sun in the solar system
Planet
Earth-like
Terrestrial
Large and small rocks or metallic masses orbiting the Sun; made up of materials similar to those that formed the planets
Asteroids
A natural chunk of rock or dust existing outside of Earth’s atmosphere
Meteoroid
All of space and the matter space contains
Universe
Solar system model that uses Earth as the reference point
Geocentric
Any of the rocky, terrestrial planets of Mercury, Venus, Earth, and Mars, whose orbits are inside the asteroid belt
Inner Planet
A disk of matter that encircles a planet and consists of numerous particles in orbit, ranging in size from dust grains up to objects tens of meters across.
Planetary ring
Small meteoroid that burns upon entry into Earth’s atmosphere.
Meteor
A unit of length equal to the distance that light travels through space in one year.
Light-Year
A curved path traveled by a satellite as it revolves around an object in space
Orbital Path
Any of the planets Jupiter, Saturn, Uranus, and Neptune, whose orbits lie beyond the asteroid belt
Outer Planet
The region between the inner and outer planets where most asteroids orbit around the Sun
Asteroid Belt
Remains of meteoroids that strike the surface of Earth or the Moon
Meteorites
A large grouping of stars,dust and gas bound together by gravity in space
Galaxy
Solar system model that is Sun-centered
Heliocentric
A planet that has a massive, deep atmosphere, like Jupiter, Saturn, Uranus, or Neptune.
Gas giants
Something that orbits around another object; for example, a moon orbiting a planet or a human-made object orbiting Earth
Satellite
Attraction between two objects with a strength that is proportional to the masses of the objects
Gravity
A large celestial body that is composed of gas and that emits light; the sun is a typical star.
Star
The Sun together with the group of planets and other celestial bodies that travel around it
Solar System
One of the highly dense planets nearest the sun; Mercury, Venus, Earth and Mars.
Terrestrial Planets
A celestial body of ice, dust, and rock with an elongated and elliptical orbit
Comet
Any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses
Law of Universal Gravitation
The sun and all of the planets and other bodies that travel around it.
Solar system