How are the moon phases formed?

Answer 1

The phases of the moon are caused by the earth's shadow being cast by the sun on to the lunar surface. As the moon rotates around the earth, and the earth rotates around the sun, the way the earth's shadow is cast gradually changes. These changes follow a very precise pattern, and so we can accurately predict them on our calendars.

Answer 2

The lunar phases are created by the orbit of the moon around the earth. When the moon rises in the east as the sun sets in the west, it will be a full moon. A lunar eclipse can only occur during a full moon.

About a week after a full moon, a half moon (waning) will be next when the moon rises approximately 6 hours after sunset. In that case, the left (western) half of the moon will be lit. Continuing around, when both the sun and the moon rise in the east at approximately the same time, you will not see the moon because the moon is the same black color as the space that surrounds it. That is a new moon. If the moon happens to be in the same orbital plain as the sun and crosses in front of the sun, blocking out the sun, that is a solar eclipse. A solar eclipse can only occur during a new moon.

When the moon rises approximately 6 hours after sunrise, (about 3 weeks after a full moon) it is a half moon (waxing). That is why we sometimes see the moon in the afternoon and into the evening. In this case, the eastern half of the moon will be lit by the sun. THe moon gradually grows as it rises 90 minutes later each day until it becomes a full moon again.

Answer 3

The moon phases are formed due to the changing angles between the Earth, the sun, and the moon as the moon orbits the Earth. As the moon moves in its orbit, different portions of its illuminated side are visible from Earth, creating the different phases such as new moon, crescent, quarter, gibbous, and full moon.