Question 1

True or false: The word 'rille' comes from the German word for 'groove' or 'furrow'.

Accepted Answer

True. It's borrowed from German 'Rille' meaning groove. Astronomers adopted the term in the 19th century for these lunar features.

Question 2

True or false: Rilles are always straight line features, never curved or meandering.

Accepted Answer

False. Sinuous rilles, such as Hadley Rille, meander like rivers across the lunar surface. Their winding paths prove that not all rilles are straight.

Question 3

True or false: Rilles on the moon were carved by ancient rivers of water, not lava.

Accepted Answer

False. Most lunar rilles are actually collapsed lava tubes or channels formed by flowing lava, not water. The moon had no significant liquid water rivers.

Question 4

True or false: Some lunar rilles are longer than the Grand Canyon.

Accepted Answer

False. The longest lunar rille, Vallis Schröteri, is about 160 km (100 miles) long, far shorter than the Grand Canyon's 446 km (277 miles). No lunar rille exceeds 300 km.

Question 5

True or false: Rilles were first discovered by telescopes in the 1600s.

Accepted Answer

False. Rilles were first clearly observed by Johann Schröter in the 1790s. Telescopes of the 1600s were too crude to resolve such narrow lunar channels.

Question 6

True or false: The longest known rille on the moon is over 300 miles long.

Accepted Answer

True. Vallis Snellius, a linear rille, is about 370 miles (592 km) long, making it the longest known rille on the Moon.

Question 7

True or false: Rilles are found only on the moon, not on any other planet or moon.

Accepted Answer

False. Rilles are not unique to the Moon; similar lava channels and grooves have been identified on other celestial bodies, including Mars and Venus.

Question 8

True or false: Apollo 15 astronauts visited a rille and collected samples of volcanic glass there.

Accepted Answer

True. Apollo 15 landed near Hadley Rille and astronauts David Scott and James Irwin collected green volcanic glass beads from the area.

Rille Trivia Questions