Have you ever wondered what causes the moon phases?
We all know that its appearance changes over time.
One important thing to notice is that exactly one half of the moon is always illuminated by the sun.
New moon occurs when the moon is positioned between the earth and sun. The entire illuminated portion of the moon is on the back side of the moon, the half that we cannot see.
At a full moon, the earth, moon, and sun are in approximate alignment, just as the new moon, but the moon is on the opposite side of the earth, so the entire sunlit part of the moon is facing us. The shadowed portion is entirely hidden from view.
The first quarter and third quarter moons (both often called a “half moon“), happen when the moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated and half in shadow.
(REF: http://www.moonconnection.com/moon_phases.phtml)
Important notes
- The changing shape of the bright part of the Moon that we see is called its phase.
- The moon is illuminated because it reflects the light from the sun. The part of the moon facing the sun is lit up. The part facing away from the sun is in darkness.
- The phases of the Moon depend on its position in relation to the sun and Earth. As the Moon makes its way around the Earth, we see the bright parts of the Moon’s surface at different angles. These are called “phases” of the Moon.
- The phases of the moon work in a cycle starting with the new moon.
- The Moon orbits the Earth.
- It takes about 28 days for the Moon to orbit the Earth.
- The Moon is held in orbit due to the Earth’s gravitational pull.
- One side of the Moon (the same side) is always facing away from the Earth.
- Did you know? Countries near the equator see the crescent moon shaped like a smile?