A solar eclipse occurs when a new moon blocks sunlight from reaching the Earth.
During an eclipse, the Moon fits almost exactly across the Sun, revealing the Sun's "corona," which is usually not visible.
Frequency and Path of Totality
Solar eclipses do not occur every month.
A solar eclipse is visible over only a small portion of the world along a path of totality.
Compared to lunar eclipses, solar eclipses are very rare at any given location because the Moon is much smaller than the Earth.
Proportions and Angular Size
The Sun is 400 times larger than the Moon, but it is also 400 times as far away.
Orbits are not perfectly circular, so the distance and angular sizes of both the Sun and the Moon vary slightly between their closest and farthest points.
Annular Eclipses
As a result of distance variations, some solar eclipses are "annular," meaning the Moon does not fully cover the Sun, leaving a visible ring of sunlight around the Moon.