An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Opposite to or reversing something.
Math.: Involving two variables that are in a mathematical relationship where, when one increases, the other decreases and vice versa.

From L. inversus, p.p. of invertere, → invert.

Vârun "inverse, upside down," from vâ- "back, backward, again, re-," variant of bâz-, from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."

A basic rule in → group theory stating that for any element a of a group there is an element a^-1 such that a * a^-1 = a^-1 * a = e.

→ inverse; → axiom.

A collision of a proton with an electron that produces a neutron and an electron neutrino. See → beta decay.

→ inverse; β, letter of Gk. alphabet; → decay.

The absorption of a photon by an electron in a strong electric field. → bremsstrahlung.

→ inverse; → bremsstrahlung.

A → scattering process by which fast-moving, energetic particles transfer energy to photons, decreasing the wavelength of the radiation. This is a particularly important effect in astrophysics and cosmology since it explains the → Sunyaev-Zel'dovich effect.

→ inverse; → Compton effect.

A line profile in which the emission is on the blue side of the absorption. It is usually interpreted as the redshift of the absorption component relative to emission lines, which necessitates infall of matter.

→ inverse; → P Cygni; → line; → profile.

A force law that applies to the → gravitational and → electromagnetic forces in which the magnitude of the force decreases in proportion to the inverse of the square of the → distance.

→ inverse; → square; → law.

The → Zeeman effect obtained in absorption. The phenomenon is observed by sending white light through an absorbing vapor when the latter is subjected to a uniform magnetic field. The laws governing the inverse effect are similar to those for the direct effect.

→ inverse; → Zeeman effect.

For a → square matrix whose → determinant is not zero, the unique matrix A^-1 satisfying the relation AA^-1 = A^-1A = I, where I is the → identity matrix.

→ matrix; → inverse.

The number which when used as a multiplier of another number (except 0) produces 1. For example (1/5) x 5 = 1; each of the numbers is the multiplicative inverse of the other.

→ multiplicative; → inverse.