| VENUS | Which is the only planet in our solar system that rotates clockwise? (5) |
| EARTH | What is the only planet in our solar system not named for a deity? |
| SOUTHERN | The hemisphere where winds rotate clockwise, around areas of low pressure (8) |
| CORIOLISFORCE | Cause for Northern Hemisphere winds to rotate clockwise, named for a French mathematician |
| NEPTUNE | The only planet in our solar system that is never visible to the naked eye (7) |
| SATURN | The only planet in the solar system with a density less than that of water |
| CERES | Body in our solar system that was considered a planet in the first half of the 19th century |
| GASGIANT | One of the four planets in our solar system that are composed chiefly of hydrogen and helium, namely Jupiter, Saturn, Uranus and Neptune (3,5) |
| SUNLIGHT | Electromagnetic radiation emanating from the star at the centre of our solar system that is a key factor in photosynthesis and a major source of vitamin D (8) |
| MILKYWAY | Galaxy containing our solar system that was studied by the Dutch astronomer Jan Oort (5,3) |
| URANUS | The only planet whose name is derived from a character in Greek mythology |
| SKIPJACK | What is the common name for the tuna fish which is the only member of the genus Katsuwonus? (8) |
| JUPITER | Named after the king of the gods in Roman mythology, the largest planet in our solar system (7) |
| EBRO | Which is the only major river of Spain that flows into the Mediterranean? (4) |
| CHEETAH | Which is the only member of the cat family that cannot completely retract its claws? (7) |
| OORTCLOUD | Bubble at the far outer reaches of the Solar System that contains trillions of icy objects |
| CYCLONES | Windstorms that rotate anticlockwise in Northern Hemisphere and clockwise in the Southern (8) |
| ECUADOR | With a national capital which is the only one beginning with the letter "Q", a South American country including the Galapagos Islands (7) |
| THEBEEGEES | Which is the only group to write and produce six consecutive number one singles in the US? (3,3,4) |
| INVERARNAN | Small hamlet near Ardlui which is the only settlement in the historical county of Perthshire with a Glasgow postcode (10) |
