An Etymological Dictionary of Astronomy and Astrophysics
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Any particle of unit spin, such as the W boson, the photon, or the rho meson.

→ vector; → meson.

The perturbation in the → primordial Universe plasma caused by → vorticity. These perturbations cause → Doppler shifts that result in → quadrupole anisotropy.

→ vector; → perturbation.

Of two vectors, a vector whose direction is perpendicular to the plane containing the two initial vectors and whose magnitude is the product of the magnitudes of these vectors and the sine of the angle between them: A x B = C, C = |AB sin α|. The direction of C is given by the → right-hand screw rule. Same as → cross product. See also → scalar product.

→ vector; → product.

A system of mathematical objects consisting of a set of (muultidimensional) vectors associated with a set of (one-dimensional) scalars, such that vectors can be added together and vectors can be multiplied by scalars while preserving the ordinary arithmetic properties (associativity, commutativity, distributivity, and so forth).

→ vector; → space.

A vector whose direction is that of propagation of a wave and whose magnitude is given by the → wave number, 2π/λ, where λ is the → wavelength, or ω/c, where ω is the → angular frequency and c is the speed of propagation.

→ wave; → number.