| ALMAGEST | Ptolemy's treatise on the motion of the stars and planets (8) |
| GAS | Expanding to fill any space, a state of matter whose behaviour, based on the motion of its particles, is explained in the kinetic molecular theory (3) |
| EVECTION | Periodical variation in the motion of the moon caused by the attraction of the sun (8) |
| MALDEMER | Sickness caused by the motion of the ocean |
| FEELSICK | React to the motion of the ocean, say |
| TACTICUS | During the 4th century BCE, he wrote On the Defense of Fortifications, one chapter of which was devoted to cryptography, making it the earliest treatise on the subject. |
| DYNAMICS | The science of the motion of bodies and action of forces with them (8) |
| UNIVERSE | All the stars and planets |
| OLDGLORY | Nickname of the Stars and Stripes (3,5) |
| ADAMS | Astronomer who explained the origin of the Leonid meteor swarms, described the motion of the Moon and independently calculated Neptune's position, by mathematical rather than observational means (5) |
| SECONDER | One who progresses the motion of drones circling London's financial centre (8) |
| ASTRONOMY | The study of the stars and planets (9) |
| BACKWASH | The motion of receding waves (8) |
| ASTRO | Study of the stars and planets, for short |
| ENCUMBER | Impede the motion of |
| TIDAL | Streaming service whose name is also an adjective describing the motion of the ocean |
| SEASICK | Queasy due to the motion of the ocean |
| TIDE | Reportedly drew the motion of the sea (4) |
| ASTROLOGY | Study of the effect that the stars and planets are said to have on our lives (9) |
| TREATISE | A work such as Ptolemy's Almagest |
