Why don't solar and lunar eclipses happen every month?
Two orders of bodies, umbra and penumbra, orbital nodes and a lunar-shadow model: why new and full Moon are not enough for an eclipse, and how to observe safely.
Tag archive
#Sun
Articles: 5
Why does the Moon keep changing shape?
Why we see crescents, half a disk and full Moon: explore lunar phases with an adjustable diagram and a lamp experiment, and test the shadow explanation.
Why do the seasons change?
How axial tilt changes solar altitude and day length, why hemispheres have opposite seasons, and what happens when tilt is removed.
Why does Earth have day and night?
Follow one place from noon into night: how rotation hides the Sun beyond the horizon and why solar and sidereal days differ.
Why does the Sun shine while the Moon reflects light?
Where sunlight gets its energy, why dark lunar rock looks bright, and how the Moon emits invisible thermal radiation of its own.