Here's why:
* Lunar Cycle: The lunar cycle (also known as the synodic month) is the time it takes for the Moon to go through all of its phases, from new moon to full moon and back again. This takes approximately 29.5 days.
* Phases: The Moon's phases are caused by the changing angles at which we see the sunlit portion of the Moon as it orbits the Earth.
* First Quarter: At the first quarter, the Moon is one quarter of the way through its cycle. It appears as a half-circle, with the illuminated side facing the east.
So, one fourth of the way through the lunar cycle is marked by the first quarter moon phase.
