Vocabulary

 A rocky mass that orbits the sun  Between Jupiter and Mars

 An imaginary line that passes through the center of a planet that it rotates about (such as Earth)

 a celestial body that moves around the sun  as it goes near the sun it forms a vapor trail of dust and gas that streams after it  Haley’s Comet

 A celestial body that orbits the sun  massive enough to assume a nearly spherical shape  not a satellite of a planet

 A planet that has a deep, massive atmosphere such as Jupiter, Saturn, Uranus, and Neptune

 Gravity is what makes pieces of matter clump together into planets, moons, and stars.  The force of attraction between objects that is due to their masses and the distance between them.  Objects closer together have a greater force of attraction than objects far apart.

 a small body of matter from outer space  Enters the atmosphere of the Earth  looks like a streak of light

 A natural satellite of a planet  Examples: Earth’s moon, Phobos, Io, Ganymede

 A path that a body follows as it travels around another body in space.  Example the mood orbits Earth, and Earth orbits the sun

 A large mass that revolves around a star  One of the celestial bodies moving around the sun

 The movement of one object around a center of another object  The Earth revolves around the sun in 365 ¼ days

 The spinning motion around the axis of a celestial body  It takes the Earth 24 hours to rotate

 A natural body revolving around a planet  An example is Earth’s moon

 Highly dense planets nearest to the sun  Mercury, Venus, Earth, and Mars

 The cycle of rising and falling of the surface of bodies of water  Caused by the attraction of the moon and the sun