Precession sentence example
The laws of motion of the ecliptic and equator are stated in the article Precession Of The Equinoxes.
The combined effect is known as the general precession.
It figured in astronomical tables until the time of Copernicus, but is now known to have no foundation in fact, being based on an error in Ptolemy's determination of precession.
Its steady retrogression among the stars became manifest to him in 130 B.C., on comparing his own observations with those made by Timocharis a century and a half earlier; and he estimated at not less than 36" (the true value being so") the annual amount of " precession."
Apply these equations to the motion of symmetrical rotors, to explain the phenomena of precession, nutation and the rate gyroscope.Advertisement
Precession The axis of rotation also precession The axis of rotation also precesses, that is it describes a circle in the sky every 51 000 years.
The displacement of the position of the First Point of Aries with time is called the precession of the equinox.
This difference creates a couple, and this couple causes precession.
The main 26,000-year effect is called luni-solar precession; the smaller, faster, periodic terms are called the nutation.
We also have to add in the planetary precession, which decreases the RA by a quantity a, during the same time interval.Advertisement
We find extremely long-lived modes of spin precession, named ' persistent precessing domains ' (PPD) at the lowest achievable temperatures.
The earth's precession leads to the precession of the equinoxes.
The modulation frequency corresponds to the Larmor precession frequency of the spin, or the Zeeman energy splitting of the spin quantum state.
Mathematics was far advanced then, that is why ancient Indian sages fixed the rate of precession of Equinoxes accurately.
Thus we have a tide-producing force tending to deform the body, the action of which is of the same nature as the force producing precession.Advertisement
Further, James Bradley discovered in 1728 the annual shifting of the stars due to the aberration of light (see Aberration), and in 1748, the complicating effects upon precession of the " nutation " of the earth's axis.
He compiled new tables of the sun and moon, long accepted as authoritative, discovered the movement of the sun's apogee, and assigned to annual precession the improved value of 55".
Taking wide-angle and fast precession, we have explored the resulting signatures and found which observational tracers are best to employ.
In 1749 he furnished a method of applying his principles to the motion of any body of a given figure; and in 1754 he solved the problem of the precession of the equinoxes, determined its quantity and explained the phenomenon of the nutation of the earth's axis.
Owing to the precession of the equinoxes it is longer than a tropical or sidereal year by 25 minutes and 2.3 seconds.Advertisement
Nasir ud-din (1201-1274) drew up the Ilkhanic Tables, and determined the constant of precession at 51".
Gravitation was thus shown to be the sole influence governing the movements of planets and satellites; the figure of the rotating earth was successfully explained by its action on the minuter particles of matter; tides and the precession of the equinoxes proved amenable to reasonings based on the same principle; and it satisfactorily accounted as well for some of the chief lunar and planetary inequalities.
James Bradley discovered in 1728 the annual shifting of the stars due to the aberration of light, and in 1748, the complicating effects upon precession of the "nutation" of the earth's axis.
They need, after a time, to be corrected, not only systematically for precession, but also empirically for proper motion.
The name for both these twisting motions is gyroscopic precession.Advertisement
In the steady motion under no force of such a body in medium, the centre of gravity describes a helix, while the axis escribes a cone round the direction of motion of the centre of ravity, and the couple causing precession is due to the dislacement of the medium.
The precession of the equinoxes is due to the fact that the earth performs a motion of this kind about its centre, and the whole class of such motions has therefore been termed precessional.
In the case of the earth it is inferred from the independent phenomenon of luni-solar precession that (CA)/A = 00313.
To find the small oscillation about a state of steady precession in which the axis makes a constant angle a with the vertical, we write O=a+X, and neglect terms of the second order in x.
Further, on examining the small variation in i/i, it appears that in a slightly disturbed slow precession the motion of any point of the axis consists of a rapid circular vibration superposed on the steady precession, so that the resultant path has a trochoidal character.Advertisement
In a slightly disturbed rapid precession the superposed vibration is elliptic-harmonic, with a period equal to that of the precession itself.
At the international conference, which met at Paris in 1896 for the purpose of elaborating a common system of constants and fundamental stars to be employed in the various national ephemerides, Newcomb took a leading part, and at its suggestion undertook the task of determining a definite value of the constant of precession, and of 1 Lionville, t.
In the other letters written in 1685 and 1686 he applies to Flamsteed for information respecting the orbits of the satellites of Jupiter and Saturn, respecting the rise and fall of the spring and neap tides at the solstices and the equinoxes, respecting the flattening of Jupiter at the poles (which, if certain, he says, would conduce much to the stating the reasons of the precession of the equinoxes), and respecting the difference between the observed places of Saturn and those computed from Kepler's tables about the time of his conjunction with Jupiter.
It is affected by the motions of Precession and Nutation, of which the former has been known since the time of Hipparchus.
These two motions are defined with greater detail in the articles Precession Of The Equinoxes and Nutation.Advertisement