Lunar rille Rima Ariadaeus bears the name of the crater Ariadaeus that marks its eastern end. It stretches East-West across the highland area between Mare Vaporum and Mare Tranquillitatis, not too far from the Apollo 11 landing site.
You can observe it with a 100mm refactor telescope or above.
Lunar Rilles
Lunar rilles (rimae in Latin, singular rima) are long, narrow, channel-like depressions on the surface of the Moon. They may have formed in several different ways, for example, after large impact events, volcanic activity, or tectonic activity.
There are several different types of rilles:
- Sinuous rilles meander in a river-like curved path. Scientists believe they are the remains of collapsed lava tubes or extinct lava flows.
- Arcuate rilles have a smooth curve and are found on the edges of the dark lunar maria. They formed when the lava flows that created a mare cooled and sank. You can find examples of this type of rille all over the moon.
- Straight rilles follow long, linear paths and you can easily identify them as they pass through craters and mountain ranges. Rima Ariadaeus is a fine straight rille specimen.
Rima Ariadaeus
Scientists believe that Rima Ariadaeus, a 300km long, 5km wide lunar rille, formed when a section of the Moon’s crust sank down between two parallel fault lines (a fault trough, like those on Earth). It appears relatively young as there are very few craters on top of the rille and the sides of the rille are very well defined. Furthermore, Rima Ariadaeus cuts across most other lunar features, indicating that it formed after these features. However, in one notable exception, plate tectonics disrupted the rille after it formed.
The bowl-shaped crater Ariadaeus marks the eastern end of the rille and is located north of Dionysius. It connects to the slightly smaller Ariadaeus A in the north-east, forming a double-crater. You can spot them all on the map of the area around Tranquility Base.