What are the dark, smooth areas on the Moon's surface, and how did they form?
AThey are oceans of water, which is why they are called 'seas' (maria)
BThey are shadows from tall mountains on the Moon
CThey are large basins filled by ancient lava flows that solidified into dark basaltic rock billions of years ago
DThey are areas where the Moon's surface has been worn smooth by wind
The dark areas are called maria (Latin for 'seas') because early observers thought they were water. They are actually giant impact basins that were later flooded by volcanic lava from the Moon's interior, which solidified into dark basaltic rock. This volcanic activity ended about 3 billion years ago. The Moon has no atmosphere, so there is no wind or water to erode the surface.
Question 2 Short Answer
Why does the same side of the Moon always face Earth?
Think about your answer, then reveal below.
Model answer: The Moon is tidally locked — its rotation period equals its orbital period (both about 27.3 days). This means the Moon rotates exactly once on its axis for every orbit around Earth, keeping the same face toward us. Tidal locking happened because Earth's gravity created a slight bulge in the Moon, and over time, gravitational interactions slowed the Moon's rotation until it synchronized with its orbit.
This is not a coincidence — it is a natural result of gravitational interaction over billions of years. Many moons in the solar system are tidally locked to their planets. The Moon does rotate; it just rotates at the same rate it orbits, which from our perspective makes it look like it is not rotating at all.
Question 3 True / False
The Moon has a permanent dark side that seldom receives sunlight.
TTrue
FFalse
Answer: False
The far side of the Moon (the side facing away from Earth) receives just as much sunlight as the near side. As the Moon orbits Earth, different parts of its surface are illuminated by the Sun. 'Dark side' is a misnomer — the correct term is 'far side.' We never see the far side from Earth because of tidal locking, not because it is dark.