longitudinal momentum
41Attitude dynamics and control — The attitude of a body is its orientation as perceived in a certain frame of reference; providing a vector along which a spacecraft is pointing is a description of its attitude. Dynamics is the term for the modeling of changing conditions, due to …
42Wigner D-matrix — The Wigner D matrix is a matrix in an irreducible representation of the groups SU(2) and SO(3). The complex conjugate of the D matrix is an eigenfunction of the Hamiltonian of spherical and symmetric rigid rotors. Definition Wigner D matrix Let j …
43Spherical harmonics — In mathematics, the spherical harmonics are the angular portion of an orthogonal set of solutions to Laplace s equation represented in a system of spherical coordinates. Spherical harmonics are important in many theoretical and practical… …
44laser — /lay zeuhr/, n. Physics. a device that produces a nearly parallel, nearly monochromatic, and coherent beam of light by exciting atoms to a higher energy level and causing them to radiate their energy in phase. Also called optical maser. [1955 60; …
45Ward-Takahashi identity — In quantum field theory, a Ward Takahashi identity is an identity between correlation functions that follows from the global or gauged symmetries of the theory, and which remains valid after renormalization. The Ward Takahashi identity of quantum …
46Beam emittance — The beam emittance of a particle accelerator is the extent occupied by the particles of the beam in space and momentum phase space as it travels. A low emittance particle beam is a beam where the particles are confined to a small distance and… …
47Self-creation cosmology — (SCC) theories are gravitational theories in which the mass of the universe is created out of its self contained gravitational and scalar fields, as opposed to the theory of continuous creation cosmology or the steady state theory which depend on …
48Orbit of the Moon — Not to be confused with Lunar orbit in the sense of a selenocentric orbit, that is, an orbit around the Moon The Moon completes its orbit around the Earth in approximately 27.3 days (a sidereal month). The Earth and Moon orbit about their… …
49lake — lake1 /layk/, n. 1. a body of fresh or salt water of considerable size, surrounded by land. 2. any similar body or pool of other liquid, as oil. 3. (go) jump in the lake, (used as an exclamation of dismissal or impatience.) [bef. 1000; ME lak(e) …
50Lake — /layk/, n. Simon, 1866 1945, U.S. engineer and naval architect. * * * I Relatively large body of slow moving or standing water that occupies an inland basin. Lakes are most abundant in high northern latitudes and in mountain regions, particularly …
