The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object.
Since Earth's diameter is 3.7 times the Moon's, its umbra extends correspondingly farther: roughly 1.4 million km (870,000 mi).
[1] The penumbra (from the Latin paene "almost, nearly" and umbra "shadow") is the region in which only a portion of the light source is obscured by the occluding body.
[2] The antumbra (from the Latin ante "before" and umbra "shadow") is the region from which the occluding body appears entirely within the disc of the light source.
If the observer moves closer to the light source, the apparent size of the occluding body increases until it causes a full umbra.
Umbra, penumbra and antumbra of Earth and images that could be seen at some points in these areas (Note: the relative size and distance of the bodies shown are not to scale.)“… The Earth’s shadow has two distinct parts,… the UMBRA is the part of the shadow where all direct sunlight is blocked by the Earth; the PENUMBRA of the shadow is where the Earth only blocks some of the sunlight.”
Umbra (A) and penumbra (B)
Umbra, penumbra, and antumbra formed through windows and shutters
Scale diagram of
Earth's shadow
, showing how the umbral cone extends beyond the
orbit of the Moon
(The Moon is indicated by the yellow dot.)
Earth's umbra, as seen during a partial lunar eclipse
Transit of Mercury
in front of the Sun, an extreme version of an annular eclipse. Mercury is visible as a black dot below and to the left of the center. The dark area above the center of the solar disk is a
sunspot
.