Umbra and Penumbra synonyms, Umbra and Penumbra antonyms - FreeThesaurus.com
umbra (redirected from Umbra and Penumbra)
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Synonyms for umbra
comparative darkness that results from the blocking of light rays
Words related to umbra
a region of complete shadow resulting from total obstruction of light
References in periodicals archive
On the facing page, the bottom diagram shows the Moon's passage through the umbra and penumbra
(pale outer fringe) of Earth's shadow.
More dramatic and interesting are views of the sharp demarcation curve between the umbra and penumbra
But that's a mistake if you really want to capture the sharp line of demarcation between umbra and penumbra
But we prefer to avoid the terms umbra and penumbra
and adopt an atmospheric model instead, where the Earth is likened to a ball of gas.