| Answer | Crossword Clue |
|---|---|
| BEAM | It travels at the speed of light |
| RAYS | Travelers at the speed of light |
| GAMMARAYS | Radioactive emissions moving at the speed of light |
| SABRE | It travels with the speed of sound. |
| DOES | Travels at a speed of |
| SOUND | It travels at Mach-1 |
