| A | B |
| free fall | the motion of a freely falling object |
| microgravity | the condition of very low gravity |
| extraterrestrial | anything that comes from beyond earth |
| radio telescope | a gigantic antenna that receives radio signals |
| the motion of a free-ly falling object | free-fall |
| the condition of low gravity | micro gravity |
| any thing that comes from beyond earth | extra-terrestrial |
| a giant antenna that receives radio signals | radiotelescope |