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  2. Umbra, penumbra and antumbra - Wikipedia

    en.wikipedia.org/wiki/Umbra,_penumbra_and_antumbra

    Umbra, penumbra, and antumbra formed through windows and shutters. The umbra (Latin for "shadow") is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. An observer within the umbra experiences a total occultation.

  3. Shadow - Wikipedia

    en.wikipedia.org/wiki/Shadow

    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.

  4. What is an umbra? A penumbra? Here's some terms to know ... - AOL

    www.aol.com/umbra-penumbra-heres-terms-know...

    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 ...

  5. Sunspot - Wikipedia

    en.wikipedia.org/wiki/Sunspot

    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.

  6. Earth's shadow - Wikipedia

    en.wikipedia.org/wiki/Earth's_shadow

    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 ...

  7. Penumbra (law) - Wikipedia

    en.wikipedia.org/wiki/Penumbra_(law)

    Umbra, penumbra, and antumbra formed through windows and shutters. Jurists have used the term "penumbra" as a metaphor for rights implied in the constitution. [1]In United States constitutional law, the penumbra includes a group of rights derived, by implication, from other rights explicitly protected in the Bill of Rights. [2]

  8. Lunar eclipse - Wikipedia

    en.wikipedia.org/wiki/Lunar_eclipse

    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.

  9. Wilson effect (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Wilson_effect_(astronomy)

    Diagram of the Wilson effect. The umbra is the darker inner circle and the penumbra is the lighter ring around the umbra. In astronomy, the Wilson effect is the perceived depression of a sunspot's umbra, or center, in the Sun's photosphere. The magnitude of the depression for the umbra is between 500 and 1000 km, with an average of 600 km. [1]