An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 13 Search : ridge
Anderson bridge
  پل ِ اندرسون   
pol-e Anderson

Fr.: pont d'Anderson   

A six-branch modification of the → Maxwell bridge that measures → inductance in terms of → resistance and → capacitance.

A. Anderson (1891, Phil. Mag. (5) 31, 329); → bridge.

pol (#)

Fr.: pont   

1) An apparent structure of → gas or → stars linking one → galaxy to another, such as → Magellanic Bridge.
2) Any one of a variety of → elctrical networks in which one branch connects two points of equal → potential and so carries no → current when the → circuit is suitably adjusted.
3) In → graph theory, a simple → edge whose removal disconnects a → graph.

M.E. brigge, O.E. brycge, from P.Gmc. *brugjo (cf. Ger. Brücke), from PIE *bhru- "log, beam."

Pol, Mid.Pers. puhl,, Av. pərətav- "bridge, passage."

Einstein-Rosen bridge
  پل ِ اینشتین-روزن   
pol-e Einstein-Rosen

Fr.: pont d'Einstein-Rosen   

A hypothetical structure that can join two distant regions of → space-time through a tunnel-like shortcut, as predicted by → general relativity. The Einstein-Rosen bridge is based on the → Schwarzschild solution of → Einstein's field equations. It is the simplest type of → wormholes.

Albert Einstein & Nathan Rosen (1935, Phys.Rev. 48, 73); → bridge.

Magellanic Bridge
  پل ِ ماژلانی   
pol-e Magellani

Fr.: pont magellanique   

A filament of → neutral hydrogen which connects the → Small Magellanic Cloud and → Large Magellanic Cloud. The Magellanic Bridge appears to result from a → close encounter between these two galaxies some 200 million years ago.

Magellanic; → bridge.

Maxwell bridge
  پل ِ ماکسول   
pol-e Maxwell

Fr.: pont de Maxwell   

A type of → Wheatstone bridge used for measuring → inductance in terms of → resistance and → capacitance.

maxwell; → bridge.

Mid-Atlantic Ridge
  روک ِ میان-اتلسی   
ruk-e miyân Atlasi

Fr.: dorsale médio-atlantique   

An immense chain of underwater mountains that runs down the middle of the Atlantic Ocean. The MAR, approximately 500-1000 km wide, extends 16,000 km from Iceland to the Antarctic Circle. The MAR is so high that it actually rises above sea level in many places, forming volcanic islands. The Azores, Ascension, St. Helena, and Iceland all arise from this great Atlantic range. The chain results from the movement of the continental plates. As these plates slowly separate, they leave gaps in the → Earth's crust. This allows molten rock from beneath the Earth's crust to reach the surface and forms a ridge. The MAR is a part of the global → mid-ocean ridge system.

mid-; → Atlantic; → ridge.

mid-ocean ridge
  روک ِ میان-اقیانوسی   
ruk-e miyân-oqyânusi

Fr.: dorsale médio-océanique   

Any of submarine mountain ranges that stretch around the world through the Atlantic Ocean and across the Pacific and Indian Oceans. Such ridges generally stand about 1000 m to 3000 m above the adjacent ocean floor and are about 500-1000 km in width.

mid-; → ocean; → ridge.

oceanic ridge
  روک ِ اقیانوسی   
ruk-e oqyânusi

Fr.: dorsale océanique   

Any section of the narrow, continuous submarine mountain chain through all the world's oceans. The oceanic ridge constitutes the most extensive mountain ridge on Earth, more than 65,000 km. Perhaps the best-known part of the ridge system is the → Mid-Atlantic Ridge.

oceanic; → ridge.

Orion Bridge
  پل ِ شکارگر   
pol-e šekârgar

Fr.: pont d'Orion   

Same as → Orion Arm.

Orion; → bridge.


Fr.: faîte, dorsale   

A long, narrow elevation of the Earth's surface, generally sharp crested with steep sides, either independently or as part of a larger mountain or hill. See also: → submarine ridge, → wrinkle ridge, → mid-Atlantic ridge.

M.E. rigge; O.E. hrycg "spine, back of a man or beast" (cf. O.Fris. hregg, Du. rug, O.H.G. hrukki, Ger. Rücken "the back").

Ruk, from dialectal Tabari ruk "mountain, ridge;" cf. (Dehxodâ) raš "hill."

submarine ridge
  روک ِ زیر-دریایی   
ruk-e zir-daryâ-yi


Geology: A long, steep elevation of the deep sea floor.

submarine; → ridge.

Wheatstone bridge
  پل ِ ویتستون   
pol-e Wheatstone

Fr.: pont de Wheatstone   

An device consisting of four → resistances in series, used to determine the value of an unknown electrical resistance when the other three resistances are known.

Named after Charles Wheatstone (1802-1875), British physicist, who extensively used the circuit (1843) but was not its inventor. Such an arrangement of four resistances was first used by Samuel Hunter Christie (1784-1865) in 1833; → bridge.

wrinkle ridge
  روک ِ چروکدار   
ruk-e corukdâr


A low, sinuous tectonic ridge on a planetary surface that resembles a wrinkle in skin or cloth. These features were first detected on the Moon, but they have also been identified on other planetary bodies such as Mars, Mercury, and Venus.

M.E., back formation from wrinkled, from O.E. gewrinclod "wrinkled, crooked," p.p. of gewrinclian "to wind, crease," from perfective prefix ge- + -wrinclian "to wind;" → ridge

Ruk, → ridge; corukdâr, from coruk "wrinkle" + dâr "having, possessor" (from dâštan "to have, to possess," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support").