| 释义 |
Hubble Astr.|hʌb(ə)l|
The name of Edwin P. Hubble (1889–1953), U.S. astronomer, used in the possessive and attrib. to designate concepts arising out of his work, as Hubble('s) constant (or † factor), the ratio of the recessional speed of a galaxy to its distance, usu. expressed in km. per second per megaparsec; also, the reciprocal of this, usu. expressed in years and capable of being interpreted as the time that has elapsed since the galaxies first began to recede (at constant speeds) from a single point; Hubble('s) law, the red shifts of the spectra of distant galaxies (and hence their speeds of recession) are proportional, on average, to their distances.
1933Monthly Notices R. Astron. Soc. XCIV. 159 We can consider a possible extension of Hubble's Law, and it will be seen that this may lead to a method for determining the cosmical constant and the sign of curvature in the generally accepted form of space-time. 1938Physical Rev. LIII. 207/1 We can also derive a relation between f and Hubble's factor u.{ddd}u is about 500 km per sec. per mega-parsec. or 1·6 × 10-17 sec.-1. 1952H. Bondi Cosmol. v. 39 The relation may be written V = r/T where T is a constant..depending..on the average intrinsic luminosity of a nebula. On this interpretation the radial velocity of a nebula is proportional to its distance... The reciprocal of the constant T is known as Hubble's constant and may be evaluated to be about 540 km./sec./megaparsec. This value leads to T = 1·8 × 109 years. 1957Encycl. Brit. VI. 502B/2 A better appreciation of the meaning of this number, H, which came to be called Hubble's constant, is given by its reciprocal 1/H = 5,400,000,000 years. 1971D. W. Sciama Mod. Cosmol. iii. 45 (caption) The expansion of the Universe as seen from another galaxy. The recession velocity is still proportional to the distance. Thus Hubble's law does not favour the Milky Way. Ibid. 46 Hubble's constant is now believed to be about 10 million years. Ibid. 48 Any systematic evolution in the intrinsic properties of the galaxies would contribute to the observed deviation from the simple Hubble law. 1972Sci. Amer. Feb. 41/2 The new value of the Hubble constant is 53 {pm} 5 kilometers per second per megaparsec, or almost exactly one-tenth of Hubble's original value. 1973Physics Bull. Nov. 652/1 Present estimates of the Hubble constant yield a value of R/Ṙ in a range (1–2) × 1010 years. |