1Two things to know first
Every month the Moon lines up — and it always trails a shadow
You only need two ideas. Watch each one:
The lineup happens every month
Once a month the Moon slides right between Earth and the Sun. Grown-ups call that a new moon. So the Moon is in the eclipse spot every single month.
The Moon always casts a shadow
Sunlight hits the Moon and leaves a long, thin shadow behind it. If that shadow lands on Earth, the Sun goes dark there. That's an eclipse.
2Two ways the Moon's path could be
A flat path vs a tilted path
Here's the secret no one tells you: the Moon's path around Earth doesn't sit flat against the Sun's path. Look at the two ways it could go:
Shadow aims dead straight
If the path were flat, the Moon would sit right on the line — so its shadow would hit Earth every lineup.
Shadow shoots over the top
The real path is tipped a little. So the Moon usually sits a bit above or below the line — and its shadow flies past Earth.
3Your turn — walk the Moon around Earth
Drag the Moon all the way around its orbit
Looking down from above. Slide the Moon around Earth for one whole month and watch for the moment it slips between Earth and the Sun — the lineup that could make an eclipse.
🛰️ Top-down view — Sun is off to the left, Earth in the middle
4Now tilt the path and watch the shadow
Lock the Moon at the lineup — then bend its path 🌑
New view: now we're looking from the side, so up and down are real. The Moon is frozen at the lineup, dead between Earth and the Sun. The only thing you'll change is how tilted its path is. Guess first — then drag the tilt.
Guess before you tilt it
Imagine the Moon's path were perfectly flat — lined up exactly with the Sun, no tilt at all. How often would we get an eclipse?