Search results
Results from the WOW.Com Content Network
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. Assuming no diffraction , for a collimated beam (such as a point source) of light, only the umbra is cast.
During an eclipse, two shadows are cast. The first is called the umbra (UM bruh). This shadow gets smaller as it goes away from the sun. It is the dark center of the eclipse shadow. The second shadow is called the penumbra (pe NUM bruh). The penumbra gets larger as it goes away from the sun.
Umbra and penumbra are Latin. The term "umbra" means shadow. The "pen" in penumbra derives from the Latin "pendere," which means to hang. The penumbra "hangs" on the umbra; the penumbra is the lighter shading that results when a light source shines on an object.
Each shadow has 3 different areas: the umbra, the penumbra, and the antumbra. The penumbra is a half-shadow that occurs when a light source is only partly covered by an object—for example, when the Moon obscures part of the Sun's disk. The other 2 areas are: Umbra – the shadow's dark center portion.
“Penumbra” and “umbra” are terms pertaining to the parts of shadows. Basically, the umbra is the darkest area while the penumbra is the lighter region which is found at the perimeter. They are often associated with astronomy specially when it comes to eclipses.
Both the Moon and Earth cast 3 shadows: and an antumbra. The umbra is the shadow's dark center portion, while the penumbra and the antumbra are different types of half-shadows. To understand why the Earth and the Moon have 3 types of shadows, let's start on a smaller scale.
The shadow comprises two concentric cones, a dark inner shadow called the umbra and a lighter outer shadow called the penumbra. Observers on Earth who are within the smaller, central umbra see the Sun completely blocked. Within the larger penumbra, the Sun is only partially blocked.