Gloom It is a notion that comes from a compound Latin word: paene ("almost" ) and umbra ("shadow" ). It is, therefore, the weak shadow that exists between the light and the darkness and that prevents perceiving where one begins and the other ends.
For example: "The murderer waited in the dim light until the victim broke into the room", "Please turn on the light: I can't read in the dim light", “My husband took me to dinner at a very romantic restaurant, where we ate in gloom and listened music classic ”.
In the dim light, the light source is partially blocked , unlike darkness. That is why the penumbra allows us to notice certain shapes or colors, although it does not allow it to be seen clearly. If there is a man Standing in a dark street, it is likely that another person will notice your presence, but you will not be able to recognize it or know how it is dressed, since it will not have enough lighting to capture details.
For the astronomy , the penumbra is the partial shadow that appears between the spaces that are fully illuminated and those that are entirely under the darkness during an eclipse In this sense, you can distinguish between gloom , antumbra and umbra .
To produce a eclipse lunar, it is necessary that the moon is located partially or totally in the cone of shadow that the Earth projects as a result of the light it receives from the Sun, and that is determined by the outer tangent conical areas of our planet and the star. On the other hand, there is the twilight zone, which presents a level of descending illumination as it approaches this shadow cone, and is determined by the interior tangent conical surfaces of the Earth and the Sun.
During an eclipse, the penumbra is characterized because any person who, located on its surface, tries to observe the Sun, only sees part of it. The same happens during the eclipses of the moon, when there are some areas of shade and some of penumbra, or only of this last class (in this case, it is practically impossible to perceive the difference in brightness of the surface of the moon with the naked eye, so it is usually studied by capturing digital images).
An eclipse is total if the lunar disk is completely covered by the umbra (the shadow of the cone cast by the Earth), partial if only part of it is overshadowed and penumbral if the satellite only manages to enter partially or totally into the penumbra of the land. As mentioned above, since the shadow of the penumbra is not very intense, it is very difficult to perceive a penumbral eclipse with the naked eye. It is important to understand that the total eclipse causes the Moon to pass through the penumbra at the beginning and the end and that it goes through the umbra completely during its process.
Gloom , on the other hand, is the name of a French band of metal gothic which was founded in 1996 and that, so far, he has released three albums.
A videogame saga for PC that started in 2007 It is also known as Gloom . The first game was called Penumbra: Overture and was followed by Penumbra: Black Plague and Penumbra: Requiem .
Within the scope of radiation oncology, the term penumbra is used to name the area that constitutes the periphery of the main focus of treatment with X-rays. This concept is defined as the lateral distance between 80% and 20% of the isodosis and its order of magnitude is the same as the result of the measurements taken in the ionization chamber.