The lunar cycle refers to the regular changes in the appearance of the Moon as it orbits the Earth. This cycle lasts about 29.5 days and includes several phases: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent. Each phase represents a different portion of the Moon's surface illuminated by the Sun. The cycle begins with the New Moon, when the Moon is not visible from Earth. As it moves in its orbit, more of its surface becomes illuminated, leading to the Full Moon, when it is fully visible. After the Full Moon, the illumination decreases until it returns to the New Moon phase, completing the cycle.