| 释义 |
relativity|rɛləˈtɪvɪtɪ|
[f. as relativist n. + -ity. Cf. F. relativité.]
1. The fact or condition of being relative, relativeness.
a1834Coleridge in Lit. Rem. (1839) IV. 223 In every religious and moral use of the word, God,..a relativity, a distinction in kind..is so essentially implied [etc.]. 1867Lewes Hist. Philos. (ed. 3) I. p. xxiv, Those who hold the doctrine of the relativity of knowledge. 1889Mivart Truth 258 The relativity of beauty is an accidental relativity.
2. The quantitative dependence of observations on the relative motion of the observer and the observed object; that branch of physics which is concerned with the description of space and time allowing for this dependence.
The modern theory of relativity, developed largely by Albert Einstein (1879–1955), is an extension and generalization of the corresponding principles in classical, or Newtonian, mechanics.
The principle of relativity, in its restricted form, is the postulate that the laws of nature have the same form in all inertial reference frames; in its more general form, it states that the laws of nature, when expressed in a suitable (‘co-variant’) form, have the same form in all reference frames, whether inertial or not.
The special theory of relativity (1905), based on the restricted principle of relativity and the hypothesis of the constancy of the speed of light in vacuo as seen by observers in any inertial frames, resulted in a theoretical framework for the unification of space and time in a four-dimensional continuum and for the equivalence of mass and energy, and showed how the uniform relative motion of observers affects their measures of length and time.
The general theory of relativity (1915), essentially a theory of gravitation, is based on the general principle of relativity, the postulated equivalence of inertial and gravitational mass, and the assumption that the results of the special theory must be valid in the limiting case of zero gravitational potential; it leads to a new set of equations of motion and the result that space-time is curved by the presence of gravitational fields.
1876J. C. Maxwell Matter & Motion vi. 84 Our whole progress up to this point may be described as a gradual development of the doctrine of relativity of all physical phenomena. Position we must evidently acknowledge to be relative. Ibid. 85 (heading) Relativity of force. 1882J. B. Stallo Concepts & Theories of Mod. Physics xii. 204 The same considerations which evince the relativity of motion also attest the relativity of its conceptual elements, space and time. 1905W. J. G. tr. Poincaré's Sci. & Hypoth. v. 76 The state of the bodies and their mutual distances at any moment will solely depend on the state of the same bodies and on their mutual distances at the initial moment, but will in no way depend on the absolute initial position of the system and of [read on] its absolute initial orientation. This is what we shall call, for the sake of abbreviation, the law of relativity. [1905Sci. Abstr. A. VIII. 2277 A. Einstein... The relativity of lengths and times.] 1906J. W. Young tr. H. Poincaré in Bull. Amer. Math. Soc. XII. 243 The principle of relativity, according to which the laws of physical phenomena must be the same for a stationary observer as for one carried along in a uniform motion of translation. Ibid. 247 Let us consider the principle of relativity; this principle is not only confirmed by our daily experience,..but it appeals to our common sense with irresistible force. And yet it also is being fiercely attacked. 1912Phil. Mag. XXIII. 375 An acceptance of the Einstein theory of relativity necessitates a revision of the Newtonian system of mechanics. 1916Monthly Notices R. Astron. Soc. LXXVI. 701 These considerations have led Einstein to his postulate of general relativity, which requires the laws of nature to be invariant for all transformations of co-ordinates. 1920R. W. Lawson tr. Einstein's Relativity vii. 20 As a result of an analysis of the physical conceptions of time and space, it became evident that in reality there is not the least incompatibility between the principle of relativity and the law of propagation of light, and that by systematically holding fast to both these laws a logically rigid theory could be arrived at. This theory has been called the special theory of relativity. 1921Nature 1 Dec. 434/2 The result is valid for both the special and the general theory of relativity. 1922E. P. Adams tr. Einstein's Meaning of Relativity iii. 68 We shall be true to the principle of relativity in its broadest sense if we give such a form to the laws [of physics] that they are valid in every such four-dimensional system of co-ordinates, that is, if the equations expressing the laws are co-variant with respect to arbitrary transformations. 1928Times 3 Dec. 8/2 The whole point of the theory of relativity is the discovery of invariants, or absolute quantities, the same to all observers, and identical throughout the universe. 1932W. T. Stace Theory of Knowl. xiv. 389 The space-time of modern relativity mechanics. 1959Listener 9 Apr. 631/2 In everyday experience, special relativity gives virtually the same results as Newtonian theory. 1968Amer. Jrnl. Physics XXXVI. 1109/1 Although the principle of relativity is subject to a possible experimental disproof in the future, the importance of the postulational approach is that it freed relativity from electrodynamics as a basis and made special relativity more universal. 1973L. J. Tassie Physics of Elementary Particles 203 An important result of the theory of special relativity is time dilatation, or the slowing down of moving clocks. 1974Encycl. Brit. Macropædia XV. 584/2 The general theory of relativity derives its origin from the need to extend the new space and time concepts of the special theory of relativity from the domain of electric and magnetic phenomena to all of physics and, particularly, to the theory of gravitation. 1976M. G. Bowler Gravitation & Relativity p. vii, Einstein's theory of gravitation, general relativity, has been verified at the one per cent level. 1978Sci. Amer. Feb. 131/1 The present understanding of the fundamental laws of nature arose from three principles: special relativity, general relativity and quantum mechanics.
3. The relative grading of posts or salaries, usu. considered within one business (internal) or in comparison with others (external). Freq. pl.
1962Rep Comm. Broadc. 1960 192 The BBC's policy on the payment of its staff takes careful account of internal and external relativities. In assessing internal relativities, the broad aim is to define the difficulty and responsibility of posts at each level over a very wide range of professions... To maintain external relativities, the Corporation draws comparisons with a suitable range of different employment. 1966New Statesman 21 Jan. 71/1 Union A makes a claim in January, on the grounds that they have fallen behind B and C. When A's claim is agreed, B makes a claim in February, because relativity has been destroyed. 1971Nature 20 Aug. 513/1 The institution pressed for the use of internal relativities to determine salaries. 1974Times 9 Feb. 1/2 The new principles and procedures for adjusting wage relativities,..since the Government agreed to set up machinery inside the Pay Board to examine major relativity claims. |