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

A small tail-like structure on a comet that, unlike most comet tails, seems to point toward the Sun. This rare event is an optical illusion due to larger dust particles left along the comet's orbit. And typically occurs when the Earth crosses the plane of the comet's orbit. It seen when the observer is in the plane of the cometary orbit.

Antitail, from → anti- "opposite, opposing, against" + → tail.

Pâddom, from pâd-, → anti-, + dom "tail."

A formation of → gas and/or → dust that streams away from the → coma of many comets under the influence of the Sun's → radiation pressure and the → solar wind. See also: → dust tail, → gas tail, → ion tail, → plasma tail, → sodium tail, → Type I tail, → Type II tail, → antitail.

→ cometary; → tail.

1) An individual or minute part; an item or → particular.
2) To relate or report with complete particulars; tell fully and distinctly (Dictionary.com).

From Fr. détail, from O.Fr. detail "small piece or quantity," literally "a cutting in pieces," from detaillier "to cut in pieces," from → de- "entirely" + taillier "to cut in pieces," from L. taliare "to split."

Pâzé, from Sogd. pâzê "portion, bit;" Kurd. pâž "part of a whole;" related to Mod.Pers. baxš "part, division," bâž "tribute, toll, impost;" ultimately from Proto-Ir. *baj- "to bestow, divide, have a share;" cf. Av. baž- (baxš-) "to divide, bestow, give a share;" O.Pers. bāji- "tribute, tax;" Mid.Pers. bâj, bâž "tribute, tax," baxtan "to distribute," baxt "luck, fate;" Skt. bhaj- "to share, distribute, apportion," Gk. phagein "to eat (to have a share of food)"; PIE base *bhag- "to share out, apportion;" → division.

1) Having many details.
2) Thorough in the treatment of details (Dictionary.com).

Adjective from → detail.

The tail of a → comet which is caused by → solar radiation pressure forcing the dust particles away from the → coma in a curved arch. Also called a → Type II tail.

→ dust; → tail.

The → ionized component of a → comet's → tail, driven nearly straight away from the → Sun Sun by the → solar wind. solar wind. Also called → ion tail, → plasma tail, and → Type I tail.

→ gas; → tail.

A member of the class of radio galaxies (→ radio galaxy) that have a strong radio emission coming from a bright "head" and a more diffuse emission from a "tail." They are often found in clusters.

→ head; → tail; → galaxy.

Of a comet, same as → gas tail.

→ gas; → tail.

The portion of a planet's → magnetosphere which is pushed away from the Sun by the solar wind. Earth's magnetosphere extends about 65,000 km on the day-side but more than 10 times further.

From → magneto- + → tail.

Same as → sodium tail.

→ neutral; → tail.

The ionized component of a comet's tail, driven nearly straight away from the Sun by the solar wind. Also called ion tail and gas tail.

→ plasma; → tail.

1) A kind of → cometary tail appearing in some → comets, such as → Hale-Bopp. Sodium tails arise from the very strong → fluorescence of their sodium atom → D lines in the visible. They are rapidly accelerated to high velocities by the Sun, forming a very straight tail distinct from the → ion tail. The release mechanism of sodium from comets is still a matter of debate. Also called → neutral tail.
2) An enormous, comet-like tail of sodium gas stretching out behind the Moon, at least 800,000 km (many hundreds, and perhaps thousands, of lunar radii). The tail is due to the strong influence of the Sun's → radiation pressure on sodium atoms (→ D line) present in the → lunar exosphere. Near → new Moon phase, the extended lunar sodium tail can be observed as it sweeps over the Earth and is gravitationally focused into a visible sodium "spot" in the → anti-solar direction. It is too faint to be detected by the human eye.

→ sodium; → tail.

1) The part that sticks out at the back of an animal's body, and that it can move.
2) Anything resembling such an appendage in form or position.
3) → cometary tail.

M.E.; O.E. tægl, from P.Gmc. *tagla- (cf. O.H.G. zagal, Ger. Zagel "tail," O.N. tagl "horse's tail").

Dom, variant domb, "tail;" Mid.Pers. dumb "tail;" Av. duma- "tail"; donbâlé, from domb + -âlé, -âl resemblance suffix, → -al.

A long stream of stars and gas, often in the form of a spectacular tail, thrown off a galaxy when it collides with another galaxy. → interacting galaxies; → merger. Two tidal tails form in each galaxy, and they are more spectacular when the masses of the two galaxies are comparable, and when their relative orbit is in the same sense as the rotation inside each spiral galaxy.

→ tidal; → tail.

The → gas tail of of a comet.

→ type; → tail.

The → dust tail of a → comet.

→ type; → tail.