You see. When sunlight is reflected by the moon, it contains green spectrum radiation. During a full moon, this radiation exceeds 17 million zeno units per second, which is required to allow an Oozaru transformation.When a Saiyan absorbs the full amount through their eyes, it triggers a reaction in their tails, allowing their transformation into the Oozaru form. Particular Saiyans, can compress a planets' atmosphere into a small power ball, which perfectly resembles a full moon.
You impressed yet!?