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

The light that has undergone → backscattering.

→ backscatter; → backscattering.

Scattering of radiation or particles through angles greater than 90° with respect to the original direction of motion.

→ scattering.

A copy of computer files that is stored separately from the original in order to protect against loss of data.

Backup "substitute, support," from → back + up.

Poštvân "prop, support, help" from pošt, → back, + -vân suffix denting protection, variant of -bân.

An auxiliary observing program to be carried out at telescope in case the atmospheric conditions make the main program unfeasible.

Backup, from → back + up; → program.

Barnâmé, → program; yadaki "reserve, substitute," from yadak "a led horse."

1) Toward the back or rear.
2) Directed toward the back or past.

→ back; → -ward.

A sort of → greenhouse effect in → stellar atmospheres where the deeper layers heat up due to overlying → opacity. The presence of numerous → bound-bound opacities of → metals amplifies the → scattering of → photons, in particular their → backscattering, forcing the → temperature to increase in order to conserve the radiation flux and the transport of energy from the interior to the outer parts of the atmosphere.

→ back; → warming; → effect.

Column of a → CCD detector that does not correctly read out charge.

Bad, from M.E. badde, but the origin of the word is not clear; → column.

Sotun, → column; bad, from Mid.Pers. wad, maybe from Old Iranian *vata- "small;" cf. Scythian bata- "small, bad," Sogdian wtγy "suffer, sorrow."

A phenomenon that occurs during a total eclipse of the Sun. Just prior to and after totality, sunlight shines through the lunar valleys on the Moon's limb, causing the dark face of the Moon to appear to be surrounded by a shining "necklace of pearls".

Baily, from Francis Baily (1774-1844), English amateur astronomer, who discovered the phenomenon during the solar eclipse of 1836. Beads "a necklace of beads or pearls; a rosary," from bead "a small, often round piece of material, such as glass, plastic, or wood, that is pierced for stringing or threading," from M.E. bede "rosary bead," from O.E. bed, bedu, gebed "prayer;" PIE *gwhedh- "to ask, pray".

Mohrehâ "beads," from mohré "a kind of small shell resembling pearls; glass or coral beads," cf. Khotanese mrâhe, may be related to morvârid, → pearl, + -hâ suffix of plurals.

Something edible placed on a hook or in a trap to attract fish or other animals as prey.

M.E., from O.Norse beita "food," O.E. bat "food," literally "to cause to bite."

Cašté "bait," related to câšni "taste," cašidan, caš- "to taste," câšt "breakfast;" Mid.Pers. câšt "meal," câšnig "taste;" cf. Skt. cas- "to eat;" Proto-Ir. caš- "to eat, to drink; to drip."

1a) A weighing device.
1b) The constellation → Libra.
2) A state of equilibrium.

M.E balaunce, from O.Fr. balance "balance, scales for weighing," from M.L. bilancia, from L.L. bilanx, from L. (libra) bilanx "(scale) having two pans," possibly from L. bis "twice" + lanx "dish, plate, scale of a balance."

Tarâzu, → Libra.

Having little or no hair on the scalp. → bald patch.

Bald from M.E. ball(e)d; Celtic bal "white patch, blaze;" Gk. phalios "having a white spot;" L. fulica "coot;" → patch.

Kal "bald," Mid.Pers. gar "bald;" Av. kaurva- "bald;" cf. Skt. kulva- "bald, thin-haired;" L. calvus "naked, bald."
Kacal may be related to kal.
Tâs, variant taz "bald;" Tabari tisâ, Saraxsi, Lâsgardi, Sangesari tusâ "empty;" related to tohi "empty;" Mid.Pers. tuhig; Av. taoš- "to become empty," pres. tusa-, caus. taošaya-, tusən "they lose their posture;" cf. Skt. tuccha-, tucchya- "empty;" L. tesqua, tesca "deserted place;" Russ. tošcij "hollow;" PIE base *teus- "to empty."

The location on the surface of the → Sun where → coronal  → magnetic field lines become tangent to the → photosphere. Bald patches play an important role in solar → magnetohydrodynamics.

→ bald, such called because of visual reference to a haircut (Titov et al. 1993, A&A 276, 564); → patch.

A set of nebular → emission line diagrams used to distinguish the ionization mechanism of → nebular gas. The most famous version consists of [N II]λ6584/Hα versus [OIII] λ5007/Hβ. The next two more commonly used BPT diagnostics are [S II] λλ6717,6731/Hα versus [O III] λ5007/Hβ and [O I] λ6300/Hα versus [O III]λ5007/Hβ. These diagrams use strong, optical lines of close proximity in the ratios to limit → reddening and → spectrophotometric effects. They are able to clearly distinguish different classes of → ionization, for example → LINERs from normal → H II regions and → active galactic nuclei.

Baldwin, J. A., Phillips, M. M., Terlevich, R., 1981 PASP 93, 5; → diagram.

A spherical or approximately spherical body, either solid or hollow.

From M.E. bal, balle, from O.Fr.; cf. O.H.G. ballo, Ger. Ball; PIE root *bhel- "to blow, swell."

Tup "ball," initially "clmup, aggregation, parcel, group" (tup tup "many"); Tabari tupa "compressed, assembled," tuppi "round;" Kurd. top "ball," topâl "round;" guy, → globe.

A rare form of lightning occurring as a bright red globe observed floating or moving through the atmosphere close to the ground. It usually is seen shortly before or after, or during, a → thunderstorm. Its duration varies from a few seconds to a few minutes. See also → Saint Elmo's fire.

→ ball; → lightning.

Of or relating to → ballistics.

A missile that after being launched and guided in the early part of its flight, travels unpowered in a ballistic trajectory.

→ ballistic; → missile.

Transfer of microbes and biochemical compounds from a planet to another due to meteoric impacts. Debris being knocked off a planet like Mars can reach escape velocity and enter the atmosphere of another planet with passenger micro-organisms intact.

→ ballistic; → panspermia.

A curved path followed by an unpowered object that is being acted upon only by gravitational forces and the friction of the medium through which it moves.

→ ballistic; → trajectory.

Audible disturbance or wave caused by the compression of air ahead of a projectile in flight.

→ ballistic; → wave.