umbra


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umbra:

see eclipseeclipse
[Gr.,=failing], in astronomy, partial or total obscuring of one celestial body by the shadow of another. Best known are the lunar eclipses, which occur when the earth blocks the sun's light from the moon, and solar eclipses, occurring when the moon blocks the sun's light
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; sunspotssunspots,
dark, usually irregularly shaped spots on the sun's surface that are actually solar magnetic storms. The spots are darker because the temperature of the spots is lower than that of the surrounding photosphere (the visible surface of the sun).
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.
Umbral and penumbral regions of a shadowclick for a larger image
Umbral and penumbral regions of a shadow

umbra

(um -bră)
1. The dark inner region of a shadow cast by an object illuminated by a light of finite size rather than a pinpoint of light. The less dark outer region of the shadow is the penumbra (see illustration). The source of light is totally obscured to someone in the umbral region but only partly obscured in the penumbral region. See eclipse.
2. See sunspots.

umbra

[′əm·brə]
(astronomy)
The dark, central region of a sunspot.
(optics)
That portion of a shadow which is screened from light rays emanating from any part of an extended source.

umbra

1. a region of complete shadow resulting from the total obstruction of light by an opaque object, esp the shadow cast by the moon onto the earth during a solar eclipse
2. the darker inner region of a sunspot
References in periodicals archive ?
In conducting this dialogue of Umbra and Black Arts poetry with Ask Your Mama, Jazz Griots itself becomes a timely act of "historical reclamation" that asserts a more expansive literary history of radical African American jazz poetry than is usually assumed in studies of the "black aesthetic" or "the 1960s." By articulating a continuity of how "jazz performs historiography" from Ask Your Mama to Wise Why's Y's, Marcoux reveals the limitations of generational constructs of African American poetry.
This begins much more dramatically when the Moon's leading (eastern) edge enters the umbra, Earth's inner shadow, where no direct sunlight reaches.
The Trina Turk, MaryJane's Home and Umbra presentations marked a huge step in Peking Handicraft's progression as a soft-home resource, according to CEO Mark Grand.
Umbra is celebrating its 30th anniversary this year and as Mandelbaum--president and the majority owner--puts it in Umbra's new catalog, it's "cause for a short pause and celebration.
Despite a top speed of Mach 3.2, it was not quick enough to catch-up with the umbra shadow that notched Mach 5, on that occasion.
In 1980, Tom Dent, another young man from New Orleans, recalled that "coming to New York in 1959 I knew I wanted to be a writer, but I didn't really know what that meant" ("Umbra Days" 105).
Este escuchara el parecer del presidente de la Conferencia episcopal umbra para las iniciativas relativas a la region umbra, o de la presidencia de la Conferencia episcopal italiana para las de mayor alcance.
A total lunar eclipse occurs when the moon moves into the darkest part of the Earth's shadow (called the umbra).
His clients include Umbra, Issey Miyake, Prada, Nambe, Magis, Mikasa, Shiseido, Giorgio Armani, Yahoo, and Danese, among others.
Umbra (2002), her recent poetry collection, was widely lauded
This second edition has newer poems that continue to showcase Thomas's energy and intelligence, including a lovely poem written in memory of Tom Dent, the political activist, poet and cofounder of the Umbra Workshop.
Budding card sharks will love these adorable Umbra Splish Splash playing cards ($5 per deck, umbra.com), The perfect accessory far a gal who knows traditional card decks are only for squares.