| A | B |
|---|
| solar system | Sun and all the bodies that orbit |
| revolution | one full orbit of one object around another |
| axis | imaginary center line which the Earth rotates around |
| rotation | one whole spin of an object on its axis |
| space probe | spacecraft that gathers data without a crew |
| comet | frozen mass of ice and dust orbiting the Sun |
| asteroid | rocky mass that revolves around the Sun |
| satellite | object in orbit around another object |
| moon phase | the part of the Moon that is illuminated and can be seen from the Earth |
