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 ?
No iba a contarlas todas en Un blues en la penumbra, pero me dio pela y dije: "
Areas having delay in peak enhancement and slightly abnormal cerebral blood volume suggested ischaemic penumbra, which is recoverable brain parenchyma.
sup][5],[6],[7],[8] In this study, ischemic penumbra was defined by decreased ASL CBF area, except in the restricted diffusion area.
Noticeably, El Gamma Penumbra doesn't have any female members.
Privately held Penumbra is based in Alameda, Calif.
There has been much debate over the effectiveness of the two treatment modalities in terms of rescuing the penumbra region and long term survival free of complications.
Hay poetas que adoptan el mundo onirico sobre la realidad sin negarla como materia prima de los suenos, que han pretendido la penumbra sobre la claridad, pues el mundo que imaginan es imagen de la orfandad o del exilio.
For each eclipse, they map the Moon's passage through the umbra and penumbra (pale outer fringe) of Earth's shadow.
silver penumbra of grief and time, glinting like the rusty metal
Bookies reckon Bale's penumbra could well be up at Madrid just weeks after arriving as the world's most expensive footballer - in fact Bernabeu chiefs were yesterday snapped by Spanish paparazzi searching desperately for a receipt.