An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -le Lag lam lan Lar lat law Lea len lep lig lig lin lin lin liq loa Loc log loo low lum lun lun Lym > >>

Number of Results: 490

Fr.: chargement   

The act of a person or thing that loads. See also: → download, → upload.

Verbal noun of → load.

lobate scarp
  تنده‌ی ِ لاپه‌ای   
tonde-ye lâpe-yi

Fr.: escarpe lobée   

A surface feature on a planet or satellite in the form of a line of cliffs. Lobate scarps are formed when planetary or lunar mantle cools down and contracts inside. The loss of volume squeezes portions of the outer crust together. Eventually, the crust breaks and some of it is pushed up, creating long cliffs that look like wrinkles. Lunar scarps are generally tens of kilometers long and less than 100 m high. They have formed during the last billion years.

Lobate "having the form of a → lobe;" → scarp.

lap (#)

Fr.: lobe   

General: A roundish projection that is part of a larger structure.
Radioastronomy: In an antenna pattern, a region of local maximum in the emitted intensity. The strongest lobe is in the pointing direction of a directional antenna and is called the main lobe.
Quasar: One of the two lobe-like structures well apart from the central source, observed in radio images of some quasars. Same as radio lobe.

From M.L. lobus, from L.L. lobus "hull, husk, pod," from Gk. lobos "lobe of the ear, vegetable pod," probably related to leberis "husk of fruits;" from PIE base *lep- "to peel, flay."

Lap "lobe," variants lâp, lâb "piece, big piece, big cut," lappé "split pea; any of the two parts of a timber split through the length," maybe cognate with Gk. lobos, as above. Alternatively, related to Pers. las "loose," PIE *leu- "to loosen, divide, cut apart" (cf. Gk. lyein "to loosen, untie, slacken," lysus "a loosening;" L. luere "to loose, release;" → analysis).

lobe pattern
  ا ُلگوی ِ لپ‌ها   
olgu-ye laphâ

Fr.: fonction de lobe   

The configuration of the response lobes of a radiotelescope.

lobe; → pattern.

lobe-dominated quasar
  کو‌آسار ِ لپ چیره   
kuasâr-e lap ciré

Fr.: quasar à lobes dominants   

A → radio-loud quasar in which the lobes dominate the whole emission. It has been conjectured that this phenomenon is an → orientation effect. If the → jet is close to the plane of the sky, the lobes will dominate. See also → core-dominated quasar.

lobe; → dominate; → quasar.

mahali (#)

Fr.: local   

Pertaining to, characteristic of, or restricted to a particular place or particular places.
See also:
local arm, → Local Bubble, → Local Group, → local inertial frame, → local interstellar cloud, → local Lorentz invariance, → local maximum, → local meridian, → local oscillator, → local position invariance, → local sidereal time, → local standard of res, → Local Supercluster, → local thermodynamic equilibrium, → local time, → local Universe, → Local Volume, → localization, → localize, → non-local thermodynamic equilibrium.

From O.Fr. local, from L.L. localis "pertaining to a place," from L. locus "place."

Mahali, related to mahal "place, locality," from Ar.

Local Arm
  بازوی ِ محلی   
bâzu-ye mahali

Fr.: bras local   

One of the → spiral arms of the → Milky Way Galaxy which contains our → solar system. Same as → Orion Arm.

local; → arm.

Local Bubble
  تنگل ِ محلی، حباب ِ ~   
tangol-e mahali, hobâb-e ~

Fr.: Bulle locale   

A region of low density in the → interstellar medium surrounding the → Solar System. It extends at least 300 → light-years in most directions and encompasses the stars of the immediate → solar neighborhood. The Local Bubble contains a hot, million-degree ionized hydrogen gas that emits in → X-rays. → Neutral hydrogen has a density approximately one tenth of the average for the interstellar medium in the Milky Way. The bubble is thought to be a result of the → shock waves from → supernovae sweeping through the region within the past two to four million years.

local; → bubble.

Local Group
  گروه ِ محلی   
goruh-e mahali (#)

Fr.: Groupe local   

A small cluster of about 40 galaxies to which our Milky Way Galaxy belongs. The Local Group occupies a volume of space nearly 10 million light-years across centered somewhere between the → Andromeda Galaxy (M31) and the Milky Way, which are the dominant galaxies of the group; Andromeda being the principal member. Both of these galaxies exhibit spiral structures, and each is attended by a large family of satellite → dwarf galaxies. The Local Group also includes a third spiral galaxy known as → Triangulum (M33), which is bound to Andromeda. The remaining members span a range of → Hubble classification types from dwarf spheroidal to Irr to Sb and Sc and cover a factor of 10 in → metallicity. The total mass of the Local Group is estimated to be about 2 x 1012 solar masses, although this value is still uncertain to within a factor of about 2. The velocities of the individual galaxies of the Local Group are not particularly high. Therefore no member is believed to be able to escape the group, which is thus considered to be gravitationally → bound. Another remarkable member of the Group is → IC 10.

local; → group.

local inertial frame
  چارچوب ِ لختی‌ناک ِ محلی، ~ لختی‌مند ِ ~   
cârcub-e laxtnâk-e mahali, ~ laxtimand-e ~

Fr.: référentiel inertiel local   

A coordinate system or frame of reference defined in the vicinity of the Earth in which Newton's first law of motion is valid; that is, a non-rotating and non-accelerating reference frame.

local; → inertial; → time.

local interstellar cloud
  ابر ِ اندر-اختری ِ محلی   
abr-e andar-axtari-ye mahali

Fr.: nuage interstellaire local   

An → interstellar cloud that surrounds the → heliosphere.

local; → interstellar; → cloud.

local Lorentz invariance
  ناورتایی ِ لورنتز ِ محلی   
nâvartâyi-ye Lorentz-e mahali

Fr.: invariance de Lorentz locale   

Einstein equivalence principle.

local; → Lorentz; → invariance.

local maximum
  بیشینه‌ی ِ محلی   
bišine-ye mahali

Fr.: maximum local   

The point x = c in an → interval where the value of the → function  f(y) is larger than the value anywhere else in that interval. In other words, f(c) ≥ f(x) for all x in the interval.

local; → maximum.

local meridian
  نیمروزان ِ محلی   
nimruzân-e mahali

Fr.: méridien local   

The meridian through any particular place, serving as the reference for local time, in contrast to the Greenwich meridian.

local; → meridian.

local minimum
  کمینه‌ی ِ محلی   
kamine-ye mahali

Fr.: minimum local   

The point x = c in an → interval where the value of the → function  f(y) is smaller than the value anywhere else in that interval. In other words, f(c) ≤ f(x) for all x in the interval.

local; → minimum.

local oscillator
  نوشگر ِ محلی   
navešgar-e mahali (#)

Fr.: oscillateur local   

The oscillator in a heterodyne or superheterodyne radio receiver which produces the radio frequency oscillations with which the received wave is combined.

local; → oscillator.

local position invariance
  ناورتایی ِ نهش ِ محلی   
nâvartâyi-ye neheš-e mahali

Fr.: invariance de position locale   

Einstein equivalence principle.

local; → position; → invariance.

local sidereal time
  زمان ِ اختری ِ محلی   
zamân-e axtari-ye mahali

Fr.: temps sidéral local   

Local time measured by the apparent motion of the stars. It is the most useful form of sidereal time since it gives the right ascension of a transiting celestial object at a given location.

local; → sidereal; → time.

Local Spur
  شخاک ِ محلی   
šaxâk-e mahali

Fr.: bras local   

Same as → Orion Arm.

local; → → spur.

local standard of rest
  استانده‌ی ِ محلی ِ آرم   
estânde-ye mahali-ye âram

Fr.: standard local de repos   

A frame of reference that turns around the Galactic center at a velocity and a distance which are the mean values for the stars in the solar neighborhood. In this reference system the stars belonging to the solar neighborhood are statistically at rest. The orbital velocity of the Local Standard of Rest around the Galaxy is about 220 km/sec.

local; → standard; → rest.

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