Moon · 2 of 8
Not Earth's Shadow
Is the dark part of the Moon the Earth's shadow?
The dark part of a crescent is not our shadow: the crescent sits beside the Sun while the shadow points away, a quarter's edge is straight, and the full Moon misses it. Only an eclipse shows the real one.
You’ll be able to explain why the Moon has phases without the Earth’s shadow, and say when the shadow does reach it.
Where and which night
Working out when this is best placed 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
- Trundle, Atwood & Christopher, "Preservice elementary teachers' conceptions of moon phases before and after instruction", Journal of Research in Science Teaching 39(7), 633–658 (2002) — the Earth's shadow is a common explanation of the phases among adults
- Espenak & Meeus, Five Millennium Canon of Lunar Eclipses, NASA/TP-2009-214172 — the size of the Earth's shadow at the Moon's distance
- NASA Science: Moon Phases — the Moon is always half lit by the Sun; the phase is how much of the lit half we see
- Meeus, Astronomical Algorithms, 2nd ed. (1998), ch. 47 and 49 — the Moon's position and its phases
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.