Wednesday, November 11, 2026. Planets, round moons, and the dwarf planets Ceres, Pluto and Makemake. Each answer must be wider than the one before.
This list has 30 answers. Open the hints one at a time, or jump straight to the full ranking.
Answers are compared by diameter, in km. Planets, the Moon and Pluto use NASA's fact-sheet diameter. Other moons use twice JPL's mean radius. Ceres uses JPL's mean diameter. Makemake uses NASA's figure of 1,430 km.
Three of the smallest answers are Mimas, Miranda and Enceladus. Start with one of them and you'll have the most room to go deeper.
The biggest answer, the ocean floor that earns a star, is Jupiter. Save it for last.
| # | Answer | Diameter |
|---|---|---|
| 1 | Jupiter planet | 142,984 km |
| 2 | Saturn planet | 120,536 km |
| 3 | Uranus planet | 51,118 km |
| 4 | Neptune planet | 49,528 km |
| 5 | Earth planet | 12,756 km |
| 6 | Venus planet | 12,104 km |
| 7 | Mars planet | 6,792 km |
| 8 | Ganymede moon of Jupiter | 5,262 km |
| 9 | Titan moon of Saturn | 5,150 km |
| 10 | Mercury planet | 4,879 km |
| 11 | Callisto moon of Jupiter | 4,821 km |
| 12 | Io moon of Jupiter | 3,643 km |
| 13 | Moon Earth's moon | 3,475 km |
| 14 | Europa moon of Jupiter | 3,122 km |
| 15 | Triton moon of Neptune | 2,705 km |
| 16 | Pluto dwarf planet | 2,376 km |
| 17 | Titania moon of Uranus | 1,578 km |
| 18 | Rhea moon of Saturn | 1,527 km |
| 19 | Oberon moon of Uranus | 1,523 km |
| 20 | Iapetus moon of Saturn | 1,469 km |
| 21 | Makemake dwarf planet | 1,430 km |
| 22 | Charon moon of Pluto | 1,212 km |
| 23 | Umbriel moon of Uranus | 1,169 km |
| 24 | Ariel moon of Uranus | 1,158 km |
| 25 | Dione moon of Saturn | 1,123 km |
| 26 | Tethys moon of Saturn | 1,062 km |
| 27 | Ceres dwarf planet | 939 km |
| 28 | Enceladus moon of Saturn | 504 km |
| 29 | Miranda moon of Uranus | 472 km |
| 30 | Mimas moon of Saturn | 396 km |
Did you know? Seven moons are wider than Pluto, and two of them, Ganymede (5,262 km) and Titan (5,150 km), are even wider than the planet Mercury (4,879 km).
Every value on this list comes from a public source, measured the same way for every answer, so the comparisons are fair.
Source: NASA Planetary Fact Sheet · JPL Solar System Dynamics: satellite physical parameters · JPL Small-Body Database (Ceres) · NASA Science: Makemake