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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 ...
What is the penumbra during an eclipse. The second shadow is called the penumbra. According to timeanddate.com, the penumbra is the lighter outer part of the moon’s shadow. It is the portion of ...
Umbra, penumbra and antumbra. A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge.
The umbra may be surrounded completely or only partially by a brighter region known as the penumbra. [23] The penumbra is composed of radially elongated structures known as penumbral filaments and has a more inclined magnetic field than the umbra. [24] Within sunspot groups, multiple umbrae may be surrounded by a single, continuous penumbra.
Since Earth's diameter is 3.7 times the Moon's, the length of the planet's umbra is correspondingly 3.7 times the average distance from the Moon to the Earth: roughly 1,400,000 km (870,000 mi). The width of the Earth's shadow at the distance of the lunar orbit is approximately 9000 km (~ 2.6 lunar diameters), which allows people of the Earth to ...
A total eclipse occurs when the observer is within the umbra, an annular eclipse when the observer is within the antumbra, and a partial eclipse when the observer is within the penumbra. During a lunar eclipse only the umbra and penumbra are applicable, because the antumbra of the Sun-Earth system lies far beyond the Moon.
The penumbra causes a subtle dimming of the lunar surface, which is only visible to the naked eye when the majority of the Moon's diameter has immersed into Earth's penumbra. [8] A special type of penumbral eclipse is a total penumbral lunar eclipse , during which the entire Moon lies exclusively within Earth's penumbra.
The umbra is the region where the light is completely blocked. In this analogy, the penumbra corresponds to fringe science, and the umbra corresponds to pseudoscience, and the places where the light is not blocked correspond to mainstream science.