the.com/umbra

the darkest heart of a shadow, where light surrenders completely and gives up the ghost

means The umbra is the fully dark central region of a shadow, where the source of light is completely blocked, as in the deepest part of a solar eclipse's shadow.

from Straight from the Latin umbra, meaning "shadow" or "shade" — the same word the Romans used for everything from a tree's cool patch to a ghost lingering in the underworld. It casts a long shadow across English: umbrella (a "little shade" from the sun, via Italian ombrella), umbrage (originally just shade, later the shadowy feeling of being offended), and adumbrate (to sketch in shadowy outline). The penumbra, that softer fringe of partial shadow, is literally the "almost-shadow," from paene ("almost") plus umbra.

eclipse core
Total solar eclipses live inside Earth's umbra
latin roots
Means shadow, parent word of umbrage and umbrella
taking umbrage
Offense once meant being thrown into shade
sunspot anatomy
Dark center of a sunspot is called umbra
three zones
Shadows split into umbra, penumbra, antumbra
for instance

umbra of earth's shadow — inner dark cone where lunar eclipses occur when moon passes through it, ~5,200 miles wide

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