black bodyn.

Brit.

/ˌblak ˈbɒdi/, U.S.

/ˌblæk ˈbɑdi/

Origin: Formed within English, by compounding; partly modelled on a German lexical item. Etymons: black adj., body n.

Etymology: < black adj. + body n. In later use after German schwarzer Körper (G. R. Kirchhoff 1860: see quot. 1860).The concept of a perfectly black body was formalized by G. R. Kirchhoff:1860 Ann. der Physik u. Chem. 109 277 Ich will solche Körper vollkommen schwarze, oder kürzer schwarze, nennen. Es ist nöthig, zuerst die Strahlung solcher schwarzen Körper zu untersuchen. [I want to call such bodies perfectly black bodies, or for short, black bodies. It is necessary to begin by examining the radiation emitted by such black bodies.]

Physics.

An idealized object that completely absorbs all the electromagnetic radiation falling on it.A black body emits radiation in a characteristic spectrum, the form of which depends on the temperature of the black body (cf. Rayleigh–Jeans n., Planck's law n. (a) at Planck n. 1b, Stefan–Boltzmann law n. at Stefan–Boltzmann n. a, Wien n.² (a)). At room temperature most of the emission of a black body is in the infrared, with negligible radiation in the visible part of the spectrum, so that the black body does indeed appear black. As its temperature increases, however, the emitted wavelengths become shorter and the black body becomes visible with a colour, at first red, then orange, white, etc.A black body can be approximated by a small hole in a large enclosure.

ΘΚΠ

the world > matter > physics > electromagnetic radiation > [noun] > all-absorbing body

black body1664

1664 R. Boyle Exper. & Considerations Colours ii. ii. 120 Black Bodies Reflect but Little of the Light that falls on them.

1723 J. Clarke tr. Rohault's Syst. Nat. Philos. I. i. xxvii. 223 The Black Body..absorbs and choaks all the Rays.

1835 Dublin Penny Jrnl. 30 May 383/1 A black body absorbs all the rays, and reflecting none, makes a blank.

1895 Astrophysical Jrnl. 2 161 It is curious that a really black body, the most important in the theory of radiation, has not so far been used by experimenters.

1911 Bull. Bureau Standards (U.S.) 7 393 Planck's equation for the intensity of radiation J, of wave length λ, from a black body at the absolute temperature θ,..appears to represent the results of all known observations.

1988 H. A. Klein Sci. Measurem. xxv. 266 The small platinum surface at the bottom of the thoria well behaves very nearly like a complete radiator, or blackbody.

2005 D. F. Gray Observ. & Anal. Stellar Photospheres (ed. 3) vi. 119 The material is then close to thermodynamic equilibrium and we expect the radiation laws of a black body to describe the radiation in these deep layers of a stellar photosphere.

Compounds

C1. General attributive, as black-body radiator, black-body spectrum, black-body temperature, etc.

ΚΠ

1901 Astrophysical Jrnl. 13 34 Observations of the distribution of energy in the black body spectrum were taken at many temperatures between 500° C. and 1100° C.

1907 C. W. Waidner & G. K. Burgess Radiation from & Melting Points of Palladium & Platinum 165 The black-body temperature, t₀, is the temperature at which the ideal black-body radiator of Kirchhoff would emit radiation of the same intensity as a substance at a temperature t₀ for the particular wave length under consideration.

1922 Jrnl. Optical Soc. Amer. 6 560 Average noon sunlight..corresponds roughly to a black body temperature of 5000° K.

1957 Encycl. Brit. III. 679/1 The black-body temperature of a source like the sun is the temperature at which a black body would emit radiation of the same intensity.

1989 R. Penrose Emperor's New Mind (1991) vii. 322 Further support..for the actual existence of the big bang, comes from what is known as the black-body background radiation.

2003 S. F. Green & M. H. Jones Introd. Sun & Stars (2004) iii. 101 The other stars, too, have spectra that are not very different from black-body spectra.

C2.

black-body radiation n. radiation with the same spectrum as the radiation emitted by a black body; radiation in thermal equilibrium with a black body.

ΘΚΠ

the world > matter > physics > electromagnetic radiation > [noun] > all-absorbing body > radiation emitted by

colour temperature1882

black-body radiation1906

1906 Science 9 Feb. 230/1 Observations..on the departure of platinum from black-body radiation for red, green and blue light.

1933 A. W. Barton Text Bk. Heat xv. 355 The radiation in a uniform temperature enclosure is sometimes called black-body radiation, since it is identical with that emitted by a black body.

1982 F. Pohl Starburst xiii. 65 The bright spot ahead of us..is in fact the fossil 2.7K blackbody radiation left over from the Big Bang.

2006 F. Wilczek Fantastic Realities 104 Dicke and Peebles proposed that Penzias and Wilson had discovered Planck's absolute—a perfect blackbody radiation that fills the universe.

This entry has been updated (OED Third Edition, September 2011; most recently modified version published online December 2021).

单词	black body
释义	black bodyn. Brit. /ˌblak ˈbɒdi/, U.S. /ˌblæk ˈbɑdi/ Origin: Formed within English, by compounding; partly modelled on a German lexical item. Etymons: black adj., body n. Etymology: < black adj. + body n. In later use after German schwarzer Körper (G. R. Kirchhoff 1860: see quot. 1860).The concept of a perfectly black body was formalized by G. R. Kirchhoff:1860 Ann. der Physik u. Chem. 109 277 Ich will solche Körper vollkommen schwarze, oder kürzer schwarze, nennen. Es ist nöthig, zuerst die Strahlung solcher schwarzen Körper zu untersuchen. [I want to call such bodies perfectly black bodies, or for short, black bodies. It is necessary to begin by examining the radiation emitted by such black bodies.] Physics. An idealized object that completely absorbs all the electromagnetic radiation falling on it.A black body emits radiation in a characteristic spectrum, the form of which depends on the temperature of the black body (cf. Rayleigh–Jeans n., Planck's law n. (a) at Planck n. 1b, Stefan–Boltzmann law n. at Stefan–Boltzmann n. a, Wien n.² (a)). At room temperature most of the emission of a black body is in the infrared, with negligible radiation in the visible part of the spectrum, so that the black body does indeed appear black. As its temperature increases, however, the emitted wavelengths become shorter and the black body becomes visible with a colour, at first red, then orange, white, etc.A black body can be approximated by a small hole in a large enclosure. ΘΚΠ the world > matter > physics > electromagnetic radiation > [noun] > all-absorbing body black body1664 1664 R. Boyle Exper. & Considerations Colours ii. ii. 120 Black Bodies Reflect but Little of the Light that falls on them. 1723 J. Clarke tr. Rohault's Syst. Nat. Philos. I. i. xxvii. 223 The Black Body..absorbs and choaks all the Rays. 1835 Dublin Penny Jrnl. 30 May 383/1 A black body absorbs all the rays, and reflecting none, makes a blank. 1895 Astrophysical Jrnl. 2 161 It is curious that a really black body, the most important in the theory of radiation, has not so far been used by experimenters. 1911 Bull. Bureau Standards (U.S.) 7 393 Planck's equation for the intensity of radiation J, of wave length λ, from a black body at the absolute temperature θ,..appears to represent the results of all known observations. 1988 H. A. Klein Sci. Measurem. xxv. 266 The small platinum surface at the bottom of the thoria well behaves very nearly like a complete radiator, or blackbody. 2005 D. F. Gray Observ. & Anal. Stellar Photospheres (ed. 3) vi. 119 The material is then close to thermodynamic equilibrium and we expect the radiation laws of a black body to describe the radiation in these deep layers of a stellar photosphere. Compounds C1. General attributive, as black-body radiator, black-body spectrum, black-body temperature, etc. ΚΠ 1901 Astrophysical Jrnl. 13 34 Observations of the distribution of energy in the black body spectrum were taken at many temperatures between 500° C. and 1100° C. 1907 C. W. Waidner & G. K. Burgess Radiation from & Melting Points of Palladium & Platinum 165 The black-body temperature, t₀, is the temperature at which the ideal black-body radiator of Kirchhoff would emit radiation of the same intensity as a substance at a temperature t₀ for the particular wave length under consideration. 1922 Jrnl. Optical Soc. Amer. 6 560 Average noon sunlight..corresponds roughly to a black body temperature of 5000° K. 1957 Encycl. Brit. III. 679/1 The black-body temperature of a source like the sun is the temperature at which a black body would emit radiation of the same intensity. 1989 R. Penrose Emperor's New Mind (1991) vii. 322 Further support..for the actual existence of the big bang, comes from what is known as the black-body background radiation. 2003 S. F. Green & M. H. Jones Introd. Sun & Stars (2004) iii. 101 The other stars, too, have spectra that are not very different from black-body spectra. C2. black-body radiation n. radiation with the same spectrum as the radiation emitted by a black body; radiation in thermal equilibrium with a black body. ΘΚΠ the world > matter > physics > electromagnetic radiation > [noun] > all-absorbing body > radiation emitted by colour temperature1882 black-body radiation1906 1906 Science 9 Feb. 230/1 Observations..on the departure of platinum from black-body radiation for red, green and blue light. 1933 A. W. Barton Text Bk. Heat xv. 355 The radiation in a uniform temperature enclosure is sometimes called black-body radiation, since it is identical with that emitted by a black body. 1982 F. Pohl Starburst xiii. 65 The bright spot ahead of us..is in fact the fossil 2.7K blackbody radiation left over from the Big Bang. 2006 F. Wilczek Fantastic Realities 104 Dicke and Peebles proposed that Penzias and Wilson had discovered Planck's absolute—a perfect blackbody radiation that fills the universe. This entry has been updated (OED Third Edition, September 2011; most recently modified version published online December 2021). < n.1664
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