How do eclipses
happen?
Eclipses are alignments: a solar eclipse is the Moon’s shadow touching Earth at new moon; a lunar eclipse is Earth’s shadow covering the Moon at full moon. The Moon’s tilted orbit is why they don’t happen monthly.
An eclipse is an alignment. When the Moon passes exactly between the Sun and Earth, its shadow touches Earth’s surface — a solar eclipse, only ever at new moon. When Earth sits exactly between the Sun and the Moon, the full moon glides into Earth’s shadow — a lunar eclipse.
Why doesn’t this happen every month? Because the Moon’s orbit is tilted about 5° to Earth’s orbit around the Sun. Most months the new moon’s shadow sails above or below Earth, and the full moon slips past Earth’s shadow. Only when the alignment coincides with the two points where the orbits cross — the nodes — do we get an eclipse season: a few weeks, twice a year, when eclipses become possible.
The two kinds are wonderfully unequal. A total solar eclipse is a local, fleeting spectacle — the Moon’s shadow paints a path only a couple of hundred kilometres wide, and totality lasts mere minutes. A total lunar eclipse is generous: everyone on Earth’s night side can watch, and totality can exceed an hour, with the Moon glowing rust-red — lit by every sunrise and sunset on Earth, bent onto it through our atmosphere.
It is also a staggering coincidence that total solar eclipses exist at all: the Sun is 400 times wider than the Moon, and — right now in cosmic history — almost exactly 400 times farther away, so the two discs match in the sky nearly perfectly.
See every eclipse from 2026 to 2030 — dates, timings and where each is visible.
This is one of seven interactive lessons in Moon Academy inside the Moon Explorer app — there, you don’t read the answer, you drag the Moon around its orbit and watch it happen.
Try the interactive lesson — freeDates and times are in Universal Time (UT). The free Moon Explorer app for Android converts everything to your local time and your exact location — fully offline, with no ads or accounts.