An eclipse of the Sun happens when the New Moon moves between the Sun and Earth, blocking out the Sun’s rays and casting a shadow on parts of Earth. The Moon’s shadow is not big enough to engulf the entire planet, so the shadow is always limited to a certain area (see map illustrations below). This area changes during the course of the eclipse because the Moon and Earth are in constant motion: Earth continuously rotates around its axis while it orbits the Sun, and the Moon orbits Earth. This is why solar eclipses seem to travel from one place to another.
Types of Solar Eclipses
There are 4 different types of solar eclipses. How much of the Sun’s disk is eclipsed, the eclipse magnitude, depends on which part of the Moon’s shadow falls on Earth.
- Partial solar eclipses occur when the Moon only partially obscures the Sun’s disk and casts only its penumbra on Earth.
- Annular solar eclipses take place when the Moon’s disk is not big enough to cover the entire disk of the Sun, and the Sun’s outer edges remain visible to form a ring of fire in the sky. An annular eclipse of the Sun takes place when the Moon is near apogee, and the Moon’s antumbra falls on Earth.
- Total solar eclipses happen when the Moon completely covers the Sun, and it can only take place when the Moon is near perigee, the point of the Moon’s orbit closest to Earth. You can only see a total solar eclipse if you’re in the path where the Moon’s casts its darkest shadow, the umbra.
- Hybrid Solar Eclipses, also known as annular-total eclipses, are the rarest type. They occur when the same eclipse changes from an annular to a total solar eclipse, and/or vice versa, along the eclipse’s path.
