Full Moon

moon phases · night sky · astronomy

When it happens. A full moon occurs about once a month when Earth lines up perfectly between the Sun and the Moon. At this moment, the sunlight shines straight onto the Moon's face that we can see from Earth, lighting it up completely.

Why it looks round. During a full moon, the entire side of the Moon facing us gets sunlight, so it appears as a bright circle. This only happens when Earth, the Sun, and the Moon are in a special straight-line arrangement.

Earth's special position. For a full moon to occur, our planet has to be sitting right in the middle between the Sun and the Moon. From the Moon's point of view, Earth would be blocking the Sun's light at that exact moment.

Regular timing. Full moons happen roughly once every 29.5 days, which is why they feel like a monthly event. This cycle happens naturally because of how the Moon orbits Earth while Earth orbits the Sun.