| Word | Meaning |
|---|---|
| Tarqeq | moon of saturn |
| Tarvos | moon of saturn |
| Taygete | moon of jupiter |
| Telescope | |
| Telesto | moon of saturn |
| Tethys | moon of saturn |
| Thalassa | Second closest moon of Neptune, orbiting the planet at an average distance of 50,075 kilometres (31,115 miles). Its diameter is about 83 km (52 miles). Thalassa was discovered in 1989 by Voyager 2. |
| Thebe | moon of jupiter |
| Thelxinoe | moon of jupiter |
| Themisto | moon of jupiter |
| Thrust | |
| Thruster | |
| Thrymr | moon of saturn |
| Thyone | moon of jupiter |
| Titan | moon of saturn |
| Titania | |
| Trinculo | |
| Triton | Neptune's largest moon. It was discovered in 1846 by British astronomer and beer brewer, William Lassell, and thought to be Neptune's only moon until Nereid was discovered in 1949. Triton is Neptune's only spherical moon with a diameter of 2,707 kilometres. It orbits at a distance of 354,800 kilometres (220,462 miles) taking 5 days and 21 hours to complete an orbit. |
