Giving one or more explanations for an observed phenomenon is a(n)

The phases of the moon and the progression of Earth’s seasons are not specifically connected, but they hinge on similar processes: one astronomical body revolving around another. Both phenomena, along with the cycle of day and night, define the most intrinsic of earthly schedules.

Earth, Moon, Sun

The sun is the focus of our solar system, holding in its gravitational pull a collection of satellites that includes the nine planets. Earth, the third planet in distance from the sun, requires a little over 365 days to complete its orbit around the star. Caught in the influence of Earth’s own gravity is its moon, which takes 28 Earth days for its revolution around our planet, and is illuminated by various degrees of reflected sunlight.

Lunar Phases

During its 28-day orbital cycle, the moon rotates on its axis once, and thus presents the same face to the Earth; the “dark side” always points away from the planet. But the moon's appearance changes throughout that orbit in a succession of lunar phases, determined by the moon’s position in relation to the Earth and sun. When the Earth lies between the moon and sun, there is a “full moon." The moon reflects its maximum amount of sunlight at this time. When the opposite configuration is true--the moon is between Earth and sun--the moon is cast in shadow, manifesting as a “new moon.”