Question

The student observed the Moon to be about 12 degrees west of the Sun. What (major) phase will the Moon be in one day later? explain

Answer 1

One day later, it would be in a New Moon Phase, at Zero degrees with the sun.

This is because of the 12-13 degrees Eastward motion of the moon. The moon’s eastward, orbital motion is easy to notice in the night sky, like moving in 360 degrees circle. The moon’s orbit carries it around Earth’s sky (almost) once a month, because that's the time it takes to orbit Earth. As a result, moon moves by about 12 to 13 degrees each day ( with respect to the fixed stars). .

Although the moon rises in the east and sets in the west each day (due to Earth’s spin), it’s also moving on the sky’s dome each day due to its own motion in orbit around Earth. Now it's established that the moon’s orbital motion is toward the east. Each day, as the moon moves another 12 to 13 degrees toward the east on the sky’s dome.

There is a slower and less noticeable motion of the moon. It’s a motion which is in front of the fixed stars. Earth's spin causes that westward motion .

You can refer to various Lunar charts for further detailed visualisation.