gravitationaladj.
/ɡravɪˈteɪʃənəl/ Of, pertaining to, or caused by gravitation; employing the principle or law of gravitation (sense 2). gravitational astronomy: a system of astronomy based, as by Sir Isaac Newton, on the theory of gravitation; also called theoretical astronomy; so gravitational astronomer.
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the world > the universe > heavenly body > [adjective] > gravitation
gravitative1799
gravitational1855
the world > matter > physics > mechanics > force > gravity > [adjective]
gravitational1855
1855 B. Powell Ess. 78 All kinds of physical agents..thermotic, electric, chemical, molecular, gravitational, luminiferous.
1869 E. Dunkin Midnight Sky 148 Several double stars suspected to belong to a common gravitational system.
1876 Newcomb in N. Amer. Rev. CXXIII. 101 Theoretical astronomy is a term somewhat too vague and inclusive; and ‘gravitational astronomy’ somewhat too narrow.
1881 Sir R. Ball in Eng. Mech. 17 June 349/1 Modern gravitational astronomers.
1889 Chambers's Jrnl. 16 Mar. 163/1 Venus has nearly the same gravitational power as the earth.
1893 R. S. Ball Story of Sun 75 The gravitational method of finding the Sun's distance.
Compounds
gravitational constant n. in classical physics, the constant of proportionality in the equation relating the strength of the gravitational attraction between two bodies to their mass and their separation, equal to approx. 6·67 × 10−11 N. m.2 kg.−2 (6·67 × 10−8 dyne cm.2 gm.−2); symbol G.
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1904 Science XIX. 928/2 The adoption of this unit of mass involves a change in the numerical value of the gravitational constant.
1966 McGraw-Hill Encycl. Sci. & Technol. (rev. ed.) VI. 264 Determining the gravitational constant by a suitable experiment is therefore equivalent to ‘weighing the Earth’.
gravitational mass n. the mass of a body as measured by the force exerted on it by a gravitational field; cf. inertial mass n. at inertial adj. Compounds.
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1918 A. S. Eddington Rep. Relativity Theory Gravitation i. 11 In astronomy..the masses of heavenly bodies are measured by their gravitational effects; naturally we cannot legitimately apply (7.8) to gravitational mass without a full discussion of the law of gravitation.
1955 Sci. Amer. June 32/2 The theory of general relativity was constructed on the basis of a physical observation of the equivalence of inertial and gravitational mass under certain simple circumstances.
gravitational potential n. the potential of a gravitational field, the gradient of which at any point is equal in magnitude and direction to the field at that point.
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1928 F. H. Newman & V. H. L. Searle Gen. Prop. Matter iii. 59 To move this unit mass from one point to another in the gravitational field would require an expenditure of work against the attraction. The amount of this work..is called the difference in gravitational potential at the points.
1938 W. M. Smart Stellar Dynamics ii. 32 The motion of an individual star at any instant will be determined by the gravitational potential of the system.
1971 Sci. Amer. May 69/1 Light emitted from such an object would have to overcome an immense gravitational potential and would be red-shifted just as it is in quasars.
gravitational system n. (also gravitational system of unit) a system of units based on a fundamental unit of weight rather than a unit of mass.
ΘΚΠ
the world > the universe > cosmology > science of observation > astronomical calculation > [noun] > unit
hour1777
astronomical unit1848
gravitational system1888
au1910
parsec1913
1888 Proc. Physical Soc. 10 41 To find J in the metre-kilogram-second gravitational system, when it is given in the British gravitational system.
1899 W. Watson Text-bk. Physics i. x. 85 Such a system of units is called a gravitational system, and it is this system which is almost exclusively used by engineers.
1966 G. W. C. Kaye & T. H. Laby Tables Physical & Chem. Constants (ed. 13) 6 It is convenient to distinguish the basic units of force in gravitational systems from the basic units of mass in other systems by using the symbols kgf for the kilogramme-force and lbf for the pound-force.
gravitational unit n. a unit the value of which depends upon the value of g, the acceleration due to gravity; formerly called gravitation unit.
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1896 E. L. Nichols & W. S. Franklin Elem. Physics I. iii. 31 (heading) Gravitational units of force.
1923 H. Moore Textbk. Intermediate Physics viii. 67 The English gravitational unit of power is one foot-pound per second.
1954 Amer. Jrnl. Physics 22 293/2 The gravitational unit of force..is related to the weight of the standard object.
gravitational water n. the water in saturated soil which can drain away under the influence of gravity.
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the world > the earth > water > [noun] > water in or percolating through soil > specific
groundwater1890
gravitational water1907
1897 L. J. Briggs in U.S. Bur. of Soils Bull. No. 10. 6 The water contained in a soil may be considered to be of three kinds—gravitation water, capillary water, and hydroscopic water.]
1907 C. W. Burkett Soils iv. 40 Three kinds of water are present in soils: gravitational water, capillary water, and hydroscopic water. Immediately after a rain, gravitational water, or that which will move under the influence of gravity, is present in the soil.
1917 J. G. Mosier & A. F. Gustafson Soil Physics & Managem. xvii. 217 The movement of gravitational water down~ward through the soil by the force of gravity is called percolation.
1960 H. Teuscher & R. Adler Soil & its Fertility vii. 85 Gravitational water is of next to no importance for plant growth.
gravitational wave n. (a) = gravity wave n. at gravity n. Compounds 2; (b) a periodic variation in gravitational field-strength which is propagated through space (the existence of such waves is not yet established with certainty).
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the world > the earth > water > flow or flowing > wave > types of waves > [noun] > other
way1578
wake1753
clean, clear breach1867
feather-spray1867
south-western1872
bow-wave1877
gravity wave1877
blind roller1888
gravitational wave1899
Kelvin wave1922
rooster tail1934
slide1935
bow shock1938
beacher1956
1899 W. Watson Text-bk. Physics iii. i. 345 The large waves seen on the surface of the sea are well-known examples of gravitational waves.
1906 E. E. Fournier d'Albe Electron Theory x. 191 If we had any means of creating or destroying matter, we could produce gravitational waves of infinite wave~length.
1922 A. S. Eddington in Proc. Royal Soc. A. 102 278 The chief point of practical interest in the problem of the spinning rod is the question whether its energy is gradually carried away by the gravitational waves which are created, so that the rotation would slow down.
1937 A. Einstein & N. Rosen in Jrnl. Franklin Inst. CCXXIII. 43 The approximate method of integration of the gravitational equations of the general relativity theory leads to the existence of gravitational waves.
1941 B. Haurwitz Dynamic Meteorol. xiv. 276 (heading) Wave motion at the free surface of a single layer. Gravitational waves.
1963 Meteorol. Gloss. (Meteorol. Office) (ed. 4) 120 Gravity wave, a type of wave, also referred to as a gravitational wave, in which the controlling forces are gravity and buoyancy.
1970 Sci. Amer. 58/3 Einstein's general theory of relativity predicts that gravitational waves should be produced by matter that is accelerating with respect to the observer.
1971 Nature 15 Jan. 185/2 Weber has..presented a plausible case for believing that his detectors may indeed have monitored frequent and sharply pulsed gravitational waves, which seem to be emanating from the centre of our galaxy.
Derivatives
graviˈtationally adv. by gravitation.
ΘΚΠ
the world > the universe > heavenly body > [adverb] > gravitation
gravitationally1887
1887 W. Thomson Sun's Heat in Good Words 150 Pieces of matter gravitationally attracted together.
1935 Discovery Dec. 352/2 Meteorites are gravitationally drawn towards the Earth.
1965 J. D. North Measure of Universe 417 Using Whittaker's and McCrea's idea of gravitational mass..and restricting his attention to what he termed a ‘gravitationally steady-state’ in which σ is held to a constant value, McVittie found [etc.].
1968 R. A. Lyttleton Myst. Solar Syst. ii. 77 The requisite pressure arises gravitationally.
Draft additions 1993
gravitational lens n. Astronomy a region of space containing a massive body whose gravitational field affects electromagnetic radiation passing through it in a manner similar to a lens.
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the world > the universe > space > [noun] > gravitational lens
gravitational lens1937
1937 Astrophysical Jrnl. 86 237 (heading) Nebulae as gravitational lenses.
1968 Science 18 Oct. 348 In some instances the foreground galaxy will act as a gravitational lens and produce distorted and (in brightness) greatly amplified images of the galaxy behind it.
1979 Nature 8 Nov. 183/1 The amazing similarities between these two objects have led to speculations that the image of a single QSO was being split by a gravitational lens in the line of sight.
1987 New Scientist 2 July 26/1 The discovery of a companion object close to the supernova discovered earlier this year has caused a flurry of activity among theorists... The most tantalising possibility is that we are seeing the effect of a gravitational lens, a black hole with a mass of a hundred thousand Suns, lying half way between our Galaxy and the supernova.
This entry has not yet been fully updated (first published 1900; most recently modified version published online March 2022).
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adj.1855