Blackbody

Domain	Definitions
Energy	An ideal substance that absorbs all radiation falling on it, and reflecting nothing. (references)
Physics	A perfect absorber of all incident radiant energy. It radiates energy solely as a function of its temperature. Source: European Union. (references)
	The thermal radiator which absorbs completely all incident radiation, whatever the wavelength, the direction of incidence or the polarisation. This radiator has, for any wavelength, the maximum spectral concentration of radiant exitance at a given temperature ; the thermal radiator which absorbs completely all electromagnetic incident radiation, whatever the wavelength, the direction of incidence or the polarisation. Source: European Union. (references)
Science	An ideal emitter which radiates energy at the maximum possible rate per unit area at each wavelength for any given temperature. A blackbody also absorbs all the radiant energy incident on it; i.e., no energy is reflected or transmitted. (references)
Solar	The theoretical "perfect" absorber of light at all wavelengths. As blackbodies heat up, they emit a characteristic double-exponential light frequency (energy) curve, which is imperfectly seen in nature. For example, Figure 2 from Shining On below shows the imperfect blackbody curve of the sun and the chunks that are ripped from it by the earth's atmosphere. (references)
Source: compiled by the editor from various references; see credits.

Specialty Definition: Blackbody

In physics a blackbody is an object that absorbs all light that falls onto it (and thus reflects none). Despite the name, blackbodies do radiate light, but they just don't reflect any. The spectrum (amount of light emitted at each wavelength) of a blackbody is very characteristic, and depends entirely on its temperature.

The light emitted by a blackbody is called blackbody radiation.
The differences between an object's spectrum and that of an idealized blackbody are sufficient to allow one to determine the chemical composition of the object.

A blackbody is an ideal emitter which radiates energy at the maximum possible rate per unit area at each wavelength for any given temperature. A blackbody also absorbs all the radiant energy incident on it: i.e. no energy is reflected or transmitted.

The term "black body" was introduced by Gustav Kirchhoff in 1862. The spectrum of a blackbody was first derived by Max Planck, who had to assume that electromagnetic radiation could propagate only on discrete packets, or quanta.

The intensity of radiation from a blackbody at temperature T is given by the Planck's Law of Radiation:

where I(ν)δν is the amount of energy per unit surface per unit time per unit solid angle emitted in the frequency range between ν and ν+δν; h is Planck's constant, c is the speed of light and k is Boltzmann's constant.

The wavelength at which the radiation is strongest is given by Wien's law, and the overall power emitted per unit area is given by the Stefan-Boltzmann law.

In the laboratory, the closest thing to a blackbody is a small hole to a cavity with a non-smooth, black surface. In astronomy, such objects as stars are frequently regarded as blackbodies, though this may be a bad approximation. An almost perfect blackbody spectrum is exhibited by the cosmic microwave background radiation.

Expression: Blackbody

Frequency of Internet Keywords: Blackbody

Modern Translations: Blackbody

Language		Translations for "blackbody"; alternative meanings/domain in parentheses.
Chinese		黑�" (bold-faced). (various references)

Danish		sort legeme (black body), planck-stråler (black body, complete radiator, full radiator, Planckian radiator), absolut sort legeme (black body, complete radiator, full radiator, Planckian radiator). (various references)

Dutch		zwarte straler (black body, complete radiator, full radiator, Planckian radiator), zwart lichaam (black body, corpus nigrum, full radiator). (various references)

Finnish		Planckin säteilyn lähde (black body, complete radiator, full radiator, Planckian radiator), musta kappale (black body, complete radiator, full radiator, Planckian radiator). (various references)

French		radiateur intégral (black body), radiateur de Planck (black body), corps noir (black body). (various references)

German		Schwarzkörper (black body), schwarzer Strahler (black body, complete radiator, full radiator, Planckian radiator), schwarzer Körper (black body, complete radiator, full radiator, Planckian radiator), Planckscher Strahler (black body, complete radiator, full radiator, Planckian radiator), Gesamtstrahler (black body, complete radiator, full radiator, Planckian radiator). (various references)

Greek		μέλαν σώμα (black, black body, complete radiator, full radiator, Planckian radiator), μελανό σώμα (black body), ακτινοβολητής � λανκ (black body, complete radiator, full radiator, Planckian radiator). (various references)

Italian		radiatore integrale (black body), radiatore di Planck (black body, complete radiator, full radiator, Planckian radiator), radiatore di pl anck (black body), radiatore completo (black body), corpo nero (black body, complete radiator, full radiator, Planckian radiator). (various references)

Pig Latin		ackbodyblay

Portuguese		radiador de Planck (black body, complete radiator, full radiator, Planckian radiator), radiador completo (black body, complete radiator, full radiator, Planckian radiator), corpo negro (black body, complete radiator, full radiator, Planckian radiator). (various references)

Spanish		radiador de Planck (black body, complete radiator, full radiator, Planckian radiator), radiador completo (black body, complete radiator, full radiator, Planckian radiator), cuerpo negro (black body, complete radiator, full radiator, Planckian radiator). (various references)

Swedish		totalstrålare (black body, complete radiator, full radiator, Planckian radiator), svart kropp (black body, complete radiator, full radiator, Planckian radiator), Planck-strålare (black body, complete radiator, full radiator, Planckian radiator), fullstrålare (black body, complete radiator, full radiator, Planckian radiator). (various references)
Source: compiled by the editor from various translation references.

Anagrams: Blackbody

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "a-b-b-c-d-k-l-o-y"
	-1 letter: blackboy.
	-3 letters: blocky.
	-4 letters: acold, alkyd, badly, baldy, balky, black, block, boyla, cabby, cabob, cloak, coaly, cobby, dobby, dobla, kabob, lobby.
	-5 letters: ably, acyl, alky, baby, back, bald, balk, blab, blob, bloc, bock, body, bola, bold, caky, calk, calo, clad, clay, clod, cloy, coal, cobb, coda, cola, cold, coly, doby, dock, kayo, kola, lack.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.