The swiftest planet
Mercury
Shared inner approach · Timor RoadAn iron core makes up about 85% of Mercury’s mass. Night-side temperatures drop to −180 °C; day-side hits 430 °C. Closest to the Sun, yet not the hottest planet — Venus holds that title.
- Type
- Terrestrial (rocky)
- Distance
- 0.39 AU
- Diameter
- 4,879 km
- Orbit
- 88 Earth days
- Moons
- None
- Model size
- 13 cm
- On the Drive
- 1.5 km from the Sun
- Found
- Known since ancient times — fastest of the classical planets
Missions
Mariner 10 (1974–75), MESSENGER orbiter (2011–2015), BepiColombo (ESA/JAXA) arriving later this decade.
Country around the board
Almost at the Sun. The closest world sits just before the AAT dome on the scaled model — a last reminder of extreme environments before Australia’s darkest skies.
Where to look
Search Google Maps for the planet plus the road or town. Boards are large, dark blue, and sit on the five approach roads — then Timor Road and Observatory Road for the inner worlds.
No service just now. This board is on your phone. Open in Maps when you next have signal.