precession period
31Nutation — See also: Nutation in plants Rotation (green), Precession (blue) and Nutation in obliquity (red) of the Earth Nutation (from Latin: nūtāre, to nod) is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric… …
32General relativity — For a generally accessible and less technical introduction to the topic, see Introduction to general relativity. General relativity Introduction Mathematical formulation Resources …
33Hindu chronology — The subject of Hindu chronology divides naturally into three parts: the calendar, the eras, and other reckonings. The Calendar The Hindus have had, from very ancient times, the system of lunisolar cycles, made by the combination of solar years,… …
34Axial tilt — Obliquity redirects here. For the book, see Obliquity (book). To understand axial tilt, consider this blue solenoid in right hand grip rule as the rotational axis of Earth, the counter clockwise direction of the magnetic field as the orbital… …
35Universe — • Presents a history of astronomy Catholic Encyclopedia. Kevin Knight. 2006. Universe Systems of the Universe † …
36History of Physics — History of Physics † Catholic Encyclopedia ► History of Physics The subject will be treated under the following heads: I. A Glance at Ancient Physics; II. Science and Early Christian Scholars; III. A Glance at Arabian Physics; IV.… …
37Sidereal time — is a measure of the position of the Earth in its rotation around its axis, or time measured by the apparent diurnal motion of the vernal equinox, which is very close to, but not identical to, the motion of stars. They differ by the precession of… …
38Hindu calendar — The Hindu calendar used in ancient times has undergone many changes in the process of regionalization, and today there are several regional Indian calendars, as well as an Indian national calendar. Most of these calendars are inherited from a… …
39Antiquity of the World — Antiquity of the World † Catholic Encyclopedia ► Antiquity of the World Various attempts have been made to establish the age of the world. Two groups of scientists have especially busied themselves with this question: physicists and… …
40nutation — nutational, adj. /nooh tay sheuhn, nyooh /, n. 1. an act or instance of nodding one s head, esp. involuntarily or spasmodically. 2. Bot. spontaneous movements of plant parts during growth. 3. Astron. the periodic oscillation observed in the… …
