Moon Mysteries: Phases and Faces

Sides of the Moon

The moon has two main sides in relation to Earth.

• Near Side –  The near side of the moon is the side that faces Earth. We can observe this side and see various lunar features, such as craters and the dark-colored flat plains formed by volcanic activity.
• Far Side –  The far side of the moon is the side that faces away from Earth. It is not visible from Earth due to the moon’s synchronous rotation. 
  • The moon takes the same amount of time to complete one rotation on its axis as it does to orbit the Earth.

What Causes The Moon’s Phases?

The different shapes of the Moon that we see at different times of the month are called the Moon’s phases. 

• The moon does not have any light of its own. It is illuminated or lit up by sunlight.
• The Sun’s light comes from one direction, and it illuminates only one-half of the Moon – the side of the Moon that is facing the Sun. The other side remains dark.
• As the moon orbits Earth, we see different portions of the illuminated half, leading to various phases of the moon.

Phases of the Moon

There are 8 phases of the moon as observed from Earth. The moon takes 29.5 days to return to the same phase.

• New Moon:
  • We cannot see the moon. The side of the moon facing us is dark because the sun is shining on the far side, the one we can’t see.
• Waxing Crescent:
  • After a few days, the moon slowly moves away from the sun. A tiny crescent-shaped sliver of light appears on the right.
• First Quarter:
  • About a week later, the moon has moved halfway around Earth. We see half the moon lit up.
• Waxing Gibbous:
  • The moon keeps moving and getting bigger each night. It is between a half-moon and a full moon now.
• Full Moon:
  • The moon is on the opposite side of Earth from the sun. The whole side facing us is fully lit up.
• Waning Gibbous:
  • After a few days, the moon starts to get smaller. It is between a full moon and a half moon now.
• Third Quarter:
  • Another week later, we see only half of the moon again, but it’s the other half from the first quarter.
• Waning Crescent:
  • The moon keeps getting smaller until only a tiny crescent-shaped sliver of light appears on the left. 

Fun Facts

Here are some fun facts about journeys to the moon!

• The moon’s far side became directly visible to humans for the first time when a Soviet spacecraft, Luna 3, captured images of it in 1959.
• The Apollo 8 astronauts from NASA were the first humans to see the far side in person when they orbited the Moon in 1968.
• The first humans landed on the moon’s surface in 1969 as part of NASA’s Apollo 11 mission.
• On Jan 3rd, 2019, China’s Chang’e 4 spacecraft mission landed a rover on the moon’s far side for the first time. 
• NASA’s Artemis program plans to land the first woman on the moon by 2026. 

Review

Let’s quickly recap what we learned about the moon’s mysteries.

• What are the two main sides of the moon? Near Side and Far Side
• How many phases of the moon do we see from Earth? 8 Phases
• How many days does it take for the moon to return to the same phase? 29.5 days
• In which phase is the moon not seen at all? New Moon
• In which two phases is the moon seen as only a tiny sliver of light? Waxing and Waning Crescent
• In which two phases is half the moon seen? First Quarter and Third Quarter