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

A galaxy whose structure is smooth without spiral arms and ellipsoidal in shape. Ellipticals are redder than spirals of similar mass. Giant ellipticals contain over 10¹² solar masses, whereas dwarf ellipticals have masses as low as 10⁷ solar masses.

→ elliptical; → galaxy.

The → polarization of an → electromagnetic radiation in which the electric vector at any point in the path of the beam describes an ellipse in a plane perpendicular to the propagation direction. Elliptical polarization results from the combination of two perpendicular → linearly polarized waves whose → phase difference is other than 0, 90, or 180°. The form of the ellipse is determined by the amplitudes of the component waves and the phase difference. → Linear polarization and → circular polarization can be considered as limiting cases of elliptical polarization.

→ elliptical; → polarization.

Light exhibiting → elliptical polarization.

→ elliptic; → polarized; → light.

The degree of divergence of an ellipse from a circle.

From elliptic-, from elliptical + → -ity.

Beyzigi, from beyzi, → ellipse, + -igi, → -ity.

Same as → Alnath.

→ Alnath.

To draw out to greater length; lengthen; extend.

From L.L. elongatus "lengthened out," p.p. of elongare "to make longer, to remove to a distance," from → ex- "out" + longus "long;" PIE base *dlonghos- "long;" cf. Av. darəga-, darəγa- "long," drājištəm "longest;" Mod.Pers. derâz "long," dir "late; long;" Skt. dīrghá- "long (in space and time);" Gk. dolikhos "long;" P.Gmc. *langgaz (Ger. lang; O.N. langr; M.Du. lanc; Goth. laggs "long;" E. long).

DerâzidanDerâzeš "to elongate," from derâz "long," Mid.Pers. drâz "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" PIE *dlonghos- "long," as above.

Made longer; long and narrow.

Past participle of → elongate.

An → elliptical orbit with a high → eccentricity.

→ elongated; → orbit.

1) Increase in length per unit of original length.
2) The angular distance of a planet from the Sun as seen from the Earth. An elongation of 0° is called → conjunction; one of 180° is called → opposition; and an elongation of 90° is called → quadrature.

→ elongate; → -tion.

A → dimensionless quantity used in → magnetohydrodynamics to describe the relative balance of → Lorentz forces to → Coriolis forces. It is given by: Λ = σB²/(ρΩ), where σ s the → electrical conductivity of the fluid, B is the typical → magnetic field strength within the fluid, ρ is the fluid → density, and Ω is the → angular velocity. A typical value for the Earth is Λ ~ 1.

Named after Walter Maurice Elsasser (1904-1991), American theoretical physicist of German origin; → number.

The brightest star in the constellation → Draco, with a visual magnitude of V = 2.23 and color B - V +1.52. It is a cool (4000 K) → giant star of spectral Type K5 III, lying 148 → light-years. Gamma Draconis has a luminosity 600 times that of the Sun and a diameter 50 times that of the Sun. It crosses the sky near the zenith point for England, a nd this was the reason why James Bradley (1693-1762) observed γ Draconis when he was trying to detect parallax and so calculate the distance. He found that the star undergoes a yearly shift of a form quite different from that expected from parallax. In a 1728 paper, Bradley announced his discovery and explained the effect as due to the → aberration of starlight . Variant names: Etamin, Etanin; Ettanin, other designations: HR 6705, HD 164058.

From Ar. At-Tinnin (التنین) "the great serpent," the Ar. rendition of the Greek constellation → Draco.

A transient upper atmospheric phenomenon occurring over a → thunderstorm in the lower → ionosphere. Elves result from especially powerful electromagnetic radiation pulses that are generated from certain lightning discharges (→ sprite). As the energy passes upwards through the base of the ionosphere it causes the gases to briefly glow for less than a thousandth of a second. This makes elves virtually impossible to see with the naked eye. Elves occur at a height of around 90-95 km, and can expand outward to several hundred kilometers in diameter, like giant expanding doughnuts.

Short for: Emission of Light and Very low-frequency perturbations from Electromagnetic pulse sources.

From E. elf "(in folklore) a small often malicious fairy; goblin; sprite;" O.E. elf, ælf, ylfe; cf. O.S. alf, O.N. alfr, Ger. alp, of unknown origin.

To flow out, issue, or proceed, as from a source or origin; come forth; originate; arise (Dictionary.com).

From L. emanatus, p.p. of emanare "flow out," figuratively "arise from, proceed from."

Runemudan "to appear, come out," literally "to show face," from ru "face," → surface, + nemudan "to show," → display.

An act or instance of emanating; something that emanates or is emanated.

→ emanate; → -tion.

A newborn star which is tightly enveloped by a surrounding cloud of gas and dust.

Ebedded p.p. of embed, from en- + bed from O.E. bed "bed," from P.Gmc. *badjam "sleeping place dug in the ground" (O.H.G. betti; Ger. bett); PIE base *bhedh- "to dig, pierce;" cf. Gk. bothyros "pit;" L. fodere "to dig," fossa "ditch;" → star.

Setâré, → star; forupušidé, p.p. of forupušidan, from foru- "below; beneath; down, downwards;" Mid.Pers. frôt "down, downwards;" O.Pers. fravata "forward, downward;" Skt. pravát- "a sloping path, the slope of a mountain" + pušidan "to cover, conceal, clothe; to wear clothes;" Mid.Pers. pôšidan, pôš- "to cover, put on, wear;" cf. Mid.Pers. pôst; Mod.Pers. pust "skin, hide;" O.Pers. pavastā- "thin clay envelope used to protect unbaked clay tablets;" Skt. pavásta- "cover;" Proto-Indo-Iranian *pauastā- "cloth."

The act of embodying; the state or fact of being embodied.

verbal noun of → embody.

1) To give a concrete form or body to an idea or quality.
2) To cause to become a body or part of a body.

From en- "in" + → body

Tanigândan, from Mid.Pers. tanig "bodily, corporal," from tan "body," → if and only if, + -ig, → -ik, + -ândan suffix of transitive verbs.

1) In several → lunisolar calendars, an → intercalary month employed to preserve a seasonal relationship between the Lunar and Solar cycles. For example, in the → Hebrew calendar the extra month, called Adar Alef, was inserted after Shvat so that the month of Nissan (month of spring) does not begin in winter.
2) In ancient Iranian → solar calendar the additional whole month of 30 days employed every 120 years to compensate for the left-over quarters of days in a calendar year of 365 days (120 years × 0.25 days = 30 days).

M.E. embolisme, from M.L. embolismus "intercalation," from Gk. emballein "to throw into, to insert," from em- "in" + ballein "to throw" (source of the medical term embolism "the obstruction (of an artery, etc.) by a clot of blood, bubble of air, etc."); → month.

Behizak, from Mid.Pers. vihezagig or vihezakik "movable," from vihezag "movement, progression," from vihez- "to move, progress;" mâh, → month.

In ancient calendars, a year that contains an → embolismic month.

→ embolismic month; → year.

1) Move out of or away from something and become visible.
2) To rise or come forth from or as if from water or other liquid (Dictionary.com).

→ ex-, + merge, → submerge.