When Earth moves between the Sun and the Moon, there is a resulting shadow that passes over the Moon. This shadow creates a lunar eclipse.
While many people think that every lunar eclipse is the same, there are actually three different types.
The first type is the Total Eclipse, which occurs when the darkest part of the Earth’s shadow, known as the umbral shadow, covers the Moon entirely. This causes it to appear as if the Moon has disappeared.
The second type is the Partial Eclipse. It occurs when only a part of the moon is covered by the Earth’s umbral shadow. This causes the shadow to be projected onto only part of the moon. Most often, a Partial Eclipse is easy to see.
The third and final type is the Penumbral Eclipse. This type of Lunar Eclipse cannot be easily seen and is thus more interesting in terms of research. In a Penumbral Eclipse, the Moon passes only through the Earth’s outer shadow, and there is no significant darkening of the Moon itself.
The Earth’s shadow contains two parts, composed of inner and outer conical shapes. The outer shadow is known as the Penumbral shadow and is used to block most Sunlight from reaching the moon. The inner shadow is known as the Umbral shadow and blocks Sunlight completely. A Lunar Eclipse occurs when the Moon is full and passes through either the Inner or Outer shadow of the Earth.