The Sun plays a crucial role in the lunar cycle, even though it's not directly responsible for the phases we see. Here's how:

* Gravity: The Sun's gravity is what keeps the Moon in orbit around the Earth.

* Illumination: The Sun is the source of light that reflects off the Moon. The different phases of the Moon are caused by the changing angles at which we see the sunlit portion of the Moon as it orbits the Earth.

* Tidal influence: The Sun's gravity also contributes to Earth's tides, though to a lesser degree than the Moon's. The combined gravitational pull of the Sun and Moon causes the strongest tides during new and full moons.

To summarize: The Sun's gravity keeps the Moon in orbit, its light illuminates the Moon, and its gravity contributes to tides. Without the Sun, there wouldn't be a lunar cycle as we know it.