Encyclopedia > Penumbra

  Article Content

Penumbra

The penumbra (Latin for mid-shadow) is the portion of a shadow that results from the source of illumination[?] being only partially blocked. Penumbras only occur when the source of light is not a point-source. As the sun is a visible disc, solar shadows have penumbras. The penumbra part of a shadow is contrasted with the umbra part of the shadow in which the light source is completely blocked.

See also: eclipse.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Wikipedia:How does one edit a page

... Tornado [[media:Sg_mrob.ogg|Sound]] [[media:Tornado.jpg|Image of a Tornado]] To link to books, you can use Wikipedia:ISBN links. ISBN ...