Moonphazee
Moon Phases — Frequently Asked Questions
Short, plain-language answers to the questions people ask most about the Moon and its phases.
Why does the Moon change shape?
It doesn't, really. The Sun always lights exactly half of the Moon. As the Moon orbits Earth, the angle between the Sun, Earth, and Moon changes, so the amount of that lit half we can see grows and shrinks. We read those changes as phases.
What phase is the Moon in today?
The phase shifts a little each night over the ~29.5-day cycle. You can estimate it by eye: a thin crescent in the evening west is a young waxing Moon; a fully lit disc rising at sunset is Full; a half Moon high at dawn is near Last Quarter. For an exact figure, an astronomy app or printed lunar calendar will give the date and illumination percentage.
How long is a lunar month?
About 29.5 days from one New Moon to the next. This is the synodic month — the basis for moon-phase tracking and for traditional lunar calendars.
What is a Supermoon?
A Supermoon is a Full (or New) Moon that lines up with perigee, the Moon's closest approach to Earth. Because it's a bit nearer, it can appear slightly larger and brighter than an average Full Moon.
Why do we always see the same side of the Moon?
The Moon spins once on its axis for every orbit it makes around Earth — a balance called tidal locking. So the same near side always faces us, and the far side (often loosely called the "dark side") stays turned away.
Are phases the same as a lunar eclipse?
No. Phases come from the Sun-Earth-Moon geometry and how much of the lit Moon faces us. A lunar eclipse is a separate event that happens only at Full Moon, when Earth's shadow actually falls across the Moon.
What is a Blue Moon?
In common usage, a Blue Moon is the second Full Moon within a single calendar month. The name has nothing to do with color — the Moon doesn't turn blue.
When is the best time to observe the Moon?
Around First and Last Quarter. With the Sun lighting the surface at a shallow angle, shadows near the terminator grow long and make craters and ridges pop — far more striking than the flat, glaring light of a Full Moon.