View from Above (North Pole)
Sunlight ->
from the Sun
Earth
Earth's Shadow
(only matters for eclipses)
Your view
Drag the Moon around Earth's orbit
As Seen from Earth
Waxing
Schematic (not to scale).
Speed
1x
5x
10x
WAXING →
Day 0 of 29.5
New
Crescent
1st Qtr
Gibbous
Full
Gibbous
3rd Qtr
Crescent
Rises ~6 PM · Sets ~6 AM
Phase
Full Moon
Angle
0
deg
Illuminated
100
%
Days since new
14.8
d
What to notice
Model notes
Observable:
the lit fraction grows or shrinks as the Moon moves.
Model:
illumination depends on the Sun-Earth-Moon phase angle $\alpha$.
Inference:
phases are geometry, not Earth's shadow.
Schematic geometry (not to scale, no orbital tilt).
Illumination uses $f = \frac{1 + \cos\alpha}{2}$ with $\alpha$ in degrees.
Earth's shadow appears only when toggled and only for eclipse insight.