| Word | Definition |
| satellite | a spacecraft that is launched into space and gathers information |
| waxing | when the moon seems to get larger and larger every night |
| phase | a change in the moon, based on its postition |
| constellation | a group of stars that form a pattern in the sky |
| star | dense ball of gas and dust and produces energy |
| revolution | movement of the Earth in a curved path around the sun |
| rotation | spinning of the Earth on its axis |
| waning | when the moon appears to get smaller and smaller every night |
| axis | the imaginary line that the Earth spins on |
| comet | an object in the solar system made up of ice, dust, and frozen gases that develop a tail of light |
| star | burning sphere of gas |
