Hubblen.
Astronomy.
Used in the possessive and attributively to designate concepts arising out of E. P. Hubble's work, as Hubble constant n. (or †Hubble factor, Hubble's constant, †Hubble's factor) the ratio of the recessional speed of a galaxy to its distance, usually expressed in km. per second per megaparsec; (also) the reciprocal of this, usually 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 law n. (also 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.
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the world > the universe > cosmology > science of observation > astronomical calculation > [noun] > part
argumentc1405
astronomicalsa1690
element1788
parameter1829
perturbative function1856
luminosity function1924
Hubble constant1933
Oort constant1941
the world > the universe > cosmology > science of observation > theory > astronomical laws > [noun] > galaxies
Hubble law1933
1938 Physical Rev. 53 207/1 We can also derive a relation between f and Hubble's factor u.…u is about 500 km per sec. per mega-parsec. or 1·6 × 10−17 sec.−1
1952 H. 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.
1957 Encycl. Brit. VI. 502 b/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.
1971 D. W. Sciama Mod. Cosmol. iii. 46 Hubble's constant is now believed to be about 10 million years.
1972 Sci. Amer. Feb. 41/2 The new value of the Hubble constant is 53 ± 5 kilometers per second per megaparsec, or almost exactly one-tenth of Hubble's original value.
1973 Physics Bull. Nov. 652/1 Present estimates of the Hubble constant yield a value of R/Ṙ in a range (1–2) × 1010 years.
1933 Monthly Notices Royal 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.
1971 D. 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.
1971 D. W. Sciama Mod. Cosmol. iii. 48 Any systematic evolution in the intrinsic properties of the galaxies would contribute to the observed deviation from the simple Hubble law.
This entry has not yet been fully updated (first published 1976; most recently modified version published online March 2019).
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