When the new moon passes exactly in front of the sun,
its shadow crosses the Earth.
The deepest part of the shadow is called the umbra.
People in the umbra see a total solar eclipse.
It takes about an hour for the shadow to cross the earth.
Two weeks later, the full moon can cross into Earth’s umbra.
Since the Earth is four times the diameter of the Moon,
the umbra is also four times larger or 16 times the area.
So lunar eclipses are more common than solar eclipses.
Everyone on the nightside of Earth can see a total lunar eclipse.
But only people in the narrow strip of totality
can see a total solar eclipse.
So, not only are lunar eclipses more common,
more people can observe each one.