By Cristel Wood
Updated Mar 24, 2022
A total solar eclipse occurs when the Moon passes directly between the Earth and the Sun, obscuring the Sun’s disk completely. This alignment is most common when the Moon is near perigee (its closest point to Earth) and the Earth is near aphelion (its farthest point from the Sun). During the brief period of darkness, the Sun’s corona—its outer atmosphere—glows like a halo around the Moon.
In a partial solar eclipse the Moon only covers a portion of the Sun. The effect is similar to a total eclipse but the Sun remains partially visible, making it more frequent and easier to observe with proper eye protection.
An annular eclipse happens when the Moon is too far from Earth to cover the Sun completely. The Moon’s silhouette sits in front of the Sun, leaving a bright “ring of fire” at sunrise or sunset.
Hybrid eclipses are rare and morph along their path. Portions of the track experience a total eclipse, while other sections show an annular eclipse, due to the Earth’s curvature and varying distance from the Moon.
During a total lunar eclipse the Moon passes entirely through Earth’s umbra, the dark inner shadow. The Moon takes on a reddish hue, a phenomenon known as the “Blood Moon,” because sunlight is refracted through Earth’s atmosphere.
In a partial lunar eclipse only part of the Moon enters the umbra, leaving the rest of the lunar disk illuminated. This type of eclipse is visible to an entire hemisphere and is more common than a total lunar eclipse.
A penumbral eclipse occurs when the Moon passes through Earth’s penumbra, the outer shadow. The dimming is subtle and often unnoticed without careful observation.
All planets with moons can experience eclipses. Gas giants like Jupiter, Saturn, Uranus, and Neptune have frequent eclipses of their moons, while Mars’s small moons rarely produce a total lunar eclipse. The specifics depend on moon size, orbital distance, and planetary position in the solar system.
