Moon · 3 of 8
The Moon by Day, and Its One Face
Why is the Moon so often up in a blue afternoon sky?
The Moon is not only a night thing: near a quarter, half its hours up are in a blue sky. And the one face it shows us means it turns once each trip round the Earth.
You’ll be able to find the Moon in a daytime sky, and explain why it shows one face.
Where and which day
Working out the Sun’s day from where you are…
Where
Kept for this guide only, until you change it here — your map settings, and every other guide, stay as they are.
Print, play outside or present
Scan with a phone's camera, or open
Sources
- NASA Science: Moon Phases — a first quarter Moon rises around midday and sets around the middle of the night; a last quarter, the reverse
- NASA Science: Tidal Locking — Earth's pull on the Moon's bulge slowed its spin until one spin took as long as one trip around Earth
- Meeus, Astronomical Algorithms, 2nd ed. (1998), ch. 47, 49 and 53 — the Moon's position, its phases, and the face it turns to us
With a keyboard, focus the sky, aim it with the up and down arrow keys, and press Enter to drop the pin at the centre of the view; or press Show me.