black body
292 Views

GC: n

CT: The ratio of the amount of radiation reflected from a surface compared to the amount of radiation that strikes it is called the surface albedo. The word “albedo” is derived from the Latin word for “white,” and indicates the “whiteness” of the surface doing the reflecting. A pure white surface, approximated on Earth by freshly fallen snow, has an albedo of unity (or 100%), indicating that all the incident radiation is reflected. A black body has an albedo of zero (or 0%), since all the incident radiation is absorbed.

S: ACS – http://www.acs.org/content/acs/en/climatescience/energybalance/predictedplanetarytemperatures.html (last access: 9 January 2015)

N: 1. A black body is a theoretical object that absorbs 100% of the radiation that hits it. Therefore it reflects no radiation and appears perfectly black.
2. A blackbody refers to an opaque object that emits thermal radiation. A perfect blackbody is one that absorbs all incoming light and does not reflect any. At room temperature, such an object would appear to be perfectly black (hence the term blackbody). However, if heated to a high temperature, a blackbody will begin to glow with thermal radiation.
In fact, all objects emit thermal radiation (as long as their temperature is above Absolute Zero, or -273.15 degrees Celsius), but no object emits thermal radiation perfectly; rather, they are better at emitting/absorbing some wavelengths of light than others. These uneven efficiencies make it difficult to study the interaction of light, heat and matter using normal objects.

S: 1. BB – http://voyager.egglescliffe.org.uk/physics/astronomy/blackbody/bbody.html (last access: 9 January 2015). 2. https://docs.kde.org/stable/en/kdeedu/kstars/ai-blackbody.html (last access: 9 January 2015).

OV: blackbody

S: GDT; TERMIUMPLUS.

SYN:
S:

CR: albedo