penumbra


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penumbra

(pĭnŭm`brə): 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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.

penumbra

(pi-num -bră)
1. See umbra.
2. See sunspots.

Penumbra

 

the space between regions of total shadow and total light formed behind an opaque body illuminated by a light source whose dimensions are comparable both with the dimensions

Figure 1

of the body and with the distance from the light source to the body (see Figure 1). Only part of the light source is visible in the penumbra; the light source is not visible in the umbra and is completely visible in the region of total light. The point of observation of a partial solar eclipse is within the penumbra formed by the moon as illuminated by the sun.

penumbra

[pə′nəm·brə]
(astronomy)
The outer, relatively light part of a sunspot.
(optics)
That portion of a shadow illuminated by only part of a radiating source.

penumbra

1. a fringe region of half shadow resulting from the partial obstruction of light by an opaque object
2. Astronomy the lighter and outer region of a sunspot
3. Painting the point or area in which light and shade blend
References in periodicals archive ?
MVI Health is supported by investments from Penumbra and licensed intellectual property and other resource contributions from Sixense Enterprises.
Volumes of hypoperfused territories, ischemic core, and penumbra area were assessed by analyzing Cerebral Blood Volume (CBV), Mean Transit Time (MTT), and Cerebral Blood Flow (CBF) maps (Figure 1).
Total Eclipse of the Moon, January 31, 2018 Eclipse Event EDT CDT MDT PDT Penumbra first visible 6:20 a.m.
The much wider part of the shadow, the penumbra, meanwhile, will cover a region on either side of the path of umbra, providing those who live in those regions to see a partial eclipse.
With tens of thousands of archival and manuscript materials that document the history of African descendant literature and culture--correspondence, pamphlets, screenplays, newspaper clippings, photographs, sheet music, ephemera, including the Penumbra Theatre Company Archives--the Givens Collection is an invaluable community and scholarly resource, and is a key foundation of Umbra Search with the Digital Public Library of America corpus providing over half of the content found in Umbra Search.
A penumbral lunar eclipse occurs when the Moon passes through the Earth's partial shadow, or penumbra. During this type of eclipse, the Moon will darken slightly but not completely.
She was signed off work in November last year, the day after the crash - but a year later Penumbra terminated her employment after a doctor ruled that she was "not fit for redeployment".
These parameters enable us to differentiate areas of penumbra and infarct zones.
Fifteen patients (mean age was 68.7 [+ or -] 8.0 years) who underwent arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) were identified as having AIS with ischemic penumbra were enrolled, where ischemic penumbra referred to the mismatch areas of ASL and DWI.
The meteorological department, providing an analytical timeframe for the eclipse said at 3:12am on Monday the moon would enter the Earth's penumbra but would not be visible to the naked eye.
Penumbra Theatre, one of the nation's oldest and largest theatres to remain from the Black Arts Movement, is transitioning from founder Lou Bellamy to his daughter Sarah.