* The Moon's Position: During a full moon, the Moon is on the opposite side of the Earth from the Sun. Imagine a straight line: Sun - Earth - Moon.
* The Sun's Influence: While the Moon is directly facing the Sun during a full moon, the Sun's light is actually reflecting off the Moon's surface towards the Earth. This is why we see a bright, full moon.
* The Earth's Role: The Earth is positioned between the Sun and the Moon, casting a shadow on the Moon's opposite side. We don't see this shadow because the Earth is illuminated by the Sun, and the Moon is too far away to have a noticeable shadow cast on it.
In short: The full moon doesn't happen because the Earth is particularly close to the Sun. It happens because the Sun, Earth, and Moon are aligned in a specific way that allows the Moon to reflect the full sunlight onto the Earth.
