01
The nodes
An eclipse needs new/full moon AND the Moon crossing Earth's orbital plane at one of two points called nodes. This model shows the tilt but not the exact node-crossing timing.
Moon · Question
Why don't we get an eclipse every month?
A solar eclipse and a lunar eclipse are opposite alignments — but every month has both a new moon and a full moon, and we don't get an eclipse at every one. Turn on the Moon's real tilt below to see why.
What's simplified
What this model leaves out.
02
Distance and size
Compressed like every model on this site — real eclipse geometry also depends on the Moon's and Sun's exact apparent size, which is why some solar eclipses are total and others are annular (a "ring of fire").
Measurable fact
How often, and how long.
2–5Solar eclipses somewhere on Earth per year.
~5.1°Tilt of the Moon's orbit relative to Earth's orbit around the Sun.
Total, partial, annularThree kinds of solar eclipse, depending on alignment and distance.
~1.5 hrsMaximum duration of a total lunar eclipse's full (umbral) phase.
Misconception check
Quick check.
Quick check
Go deeper
Keep exploring.
Next in this series →
Tidal locking ↗
Why we only ever see one side of the Moon.
Moon
Moon phases
The everyday version of this alignment — no tilt, just phase shape.
Home
Solar system model
Back to the full interactive 3D solar system.