Lunar Basin · Basalt Plain
Mare Tranquillitatis: The Historic Sea of Tranquility
A vast lunar mare formed by ancient volcanic flooding within an impact basin, immortalised as the historic touchdown site of Apollo 11 in July 1969.
Feature Profile
- Feature type
- mare
- Coordinates
- 8.35° N · 30.83° E
- Diameter
- 875.74884 km
- Dimensions
- 876 km
- IAU approval
- 1935/01/01 00:00:00
- LAC quadrangle
- LAC-61 · Taruntius
- Age
- ≈ 3.9 Ga
- Geological Period
- Upper Imbrian
- Status
- Historic Landing Site (Statio Tranquillitatis)
Background
Mare Tranquillitatis (the Sea of Tranquility) is an extensive lunar mare situated on the eastern near side of the Moon. The IAU Gazetteer records a diameter of approximately 876 kilometres. Its dark volcanic basalts fill an ancient impact basin and include titanium-rich units.
Unlike many other lunar circular maria such as Mare Imbrium or Mare Crisium, Tranquillitatis possesses an irregular, multi-lobed outline that merges into Mare Serenitatis to the northwest and Mare Fecunditatis to the southeast.
On 20 July 1969, the Apollo 11 Lunar Module Eagle touched down in southwestern Mare Tranquillitatis at 0.674° N, 23.473° E, marking humanity's first landing on another celestial body. Neil Armstrong and Buzz Aldrin explored the basalt plains, collecting 21.5 kilograms of lunar surface material that revealed an age of 3.6 to 3.9 billion years.
Through Craterra's global lunar simulation, visitors can inspect the vast basalt expanses of Mare Tranquillitatis in full 3D, fly down to the Apollo 11 landing coordinates, and explore the subtle wrinkle ridges (dorsa) and impact craters scarring the ancient lunar seafloor.
Name origin
"Sea of Tranquility."