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

Occurring at or near the beginning of a period of time, process, or sequence of events.

M.E. erlich (adj.), erliche (adv.); O.E. ærlice, from ær "soon, ere" (from P.Gmc. *airiz, from PIE *āier- "day, morning," cf. Av. ayar- "day, day time," ayarə.drājah- "duration of one day," ayarə.bara- "day's ride," Mid/Mod.Pers. parēr "the day before yesterday," from *parā.ayer- "the day before") + -lice "-ly," adverbial suffix.

Âqâzin adj. of âqâz "beginning," from Proto-Iranian *āgaHz-, from prefix ā- + *gaHz- "to run, start," cf. Sogdian āγāz "beginning, start" (Cheung 2007).

A fairly long-lived step in the evolution of → low-mass and → intermediate-mass stars when helium burning shifts from the center to a shell around the core. At this phase the stellar luminosity is provided almost entirely by → helium shell burning. The He-shell burning generally adds mass to the growing carbon/oxygen core, resulting in → degenerate matter due to its increasing density.

→ early; → AGB; → phase.

A period in the evolution of the → solar system when the planets and satellites were in the process of formation.

→ early; → solar; → system.

A star near the beginning of the → spectral classification sequence. A star of → spectral type O, B, A, or F0 to F5. Same as → early-type star.

→ early; → spectral; → class; → star.

A qualitative term used to describe a phase in the history of the Universe, from the → Big Bang event to the apparition of the first structures (seeds of future galaxies), at a → redshift around 30.

→ early; → universe.

In the → Hubble classification, galaxies on the left part of the → Hubble sequence. Early-type galaxies tend to have redder colors, higher average surface brightnesses, and lower → neutral hydrogen content than → late-type galaxies. This terminology is based on the obsolete and erroneous idea that → elliptical and → lenticular galaxies might be evolutionary precursors to → spiral and → barred spiral galaxies.

→ early; → type; → galaxy.

Hot, luminous stars of → spectral type O, B, A, and F0 to F5. They were originally thought, wrongly, to be at an earlier stage of evolution than → late-type stars. See also → spectral classification.

→ early; → type; → star.

The contradiction between a colder Sun (about 30% less luminous) some 4 billion years ago, as predicted by models, and the warm ancient Terrestrial and Martian climates derived from geological evidence.

→ faint; → early; → sun; → paradox.

In a manner characterized by first-degree algebraic terms.

Adverb of → linear.

A set of objects x₁, x₂, ..., x_n (→ vectors, → matrices, → polynomials, etc.) on a given set if there is a linear combination of them: a₁x₁ + a₂x₂ + ... + a_nx_n, which is zero, but at least one of the coefficients is non-zero. For example the binomials (2x + y) and (6x + 3y) are linearly dependent, since 3(2x + y) - (6x + 3y) = 0.

→ linearly; → dependent.

1) A set of objects x₁, x₂, ..., x_n (→ vectors, → matrices, → polynomials, etc.) if it si not → linearly dependent.
2) Of two particular solutions (y₁, y₂) of a → homogeneous linear differential equation of the second order (y^'' + a₁ y^' + a₂y = 0) on an interval [a, b], if their ratio in this interval is not a constant: y₁/y₂≠ constant.

→ linearly; → independent.

Light exhibiting → linear polarization.

→ linearly; → polarized; → light.