ellipticity
31Galaxy — This article is about the astronomical structure. For other uses, see Galaxy (disambiguation). NGC 4414, a typical spiral galaxy in the constellation Coma Berenices, is about 55,000 light years in diameter and approximately 60 million light… …
32Geodesy — (pronEng|dʒiːˈɒdɪsi [OED] ), also called geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three dimensional time varying… …
33Space elevator — A space elevator for Earth would consist of a cable anchored to the Earth s equator, reaching into space. By attaching a counterweight at the end (or by further extending the cable upward for the same purpose), the center of mass is kept well… …
34Gaussian beam — In optics, a Gaussian beam is a beam of electromagnetic radiation whose transverse electric field and intensity (irradiance) distributions are well approximated by Gaussian functions. Many lasers emit beams that approximate a Gaussian profile, in …
35Time standard — A time standard is any officially recognized specification for measuring time: either the rate at which time passes; or points in time; or both. For example, the standard for civil time specifies both time intervals and time of day. A time scale… …
36Pendulum — This article is about pendulums. For other uses, see Pendulum (disambiguation). Simple gravity pendulum model assumes no friction or air resistance …
37Sundial — A sundial is a device that measures time by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style (a thin rod or a sharp, straight edge) onto a flat surface marked with lines indicating… …
38Big Spring, Texas — Infobox Settlement official name = Big Spring, Texas, USA settlement type = City nickname = The Spring City imagesize = image caption = Big Spring s Municipal Auditorium and Statue of Liberty, with the old Settles Hotel in the background. mapsize …
39Equatorial bulge — An equatorial bulge is a bulge which a planet may have around its equator, distorting it into an oblate spheroid. The Earth has an equatorial bulge of 42.72 km (26.5 miles) due to its rotation: its diameter measured across the equatorial plane… …
40Solar time — On a prograde planet like the Earth, the sidereal day is shorter than the solar day. At time 1, the Sun and a certain distant …
