An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 465
  ریگن‌بردنی، دریگیدنی   
riganbordani, darigidani

Fr.: dont on peut hériter, qui peut hériter   


inherit; → -able.

  ریگن‌داشتی، ریگنداشتی   

Fr.: héréditaire   

1) Passing, or capable of passing, naturally from parent to offspring through the genes: Blue eyes are hereditary in our family.
2) Of or relating to inheritance or heredity (

Of or relating to → heredity.

  ریگن‌داشت، ریگنداشت   

Fr.: hérédité   

The passing on of physical or mental characteristics genetically from one generation to another (

M.E., from M.Fr. hérédité, from O.Fr. eredite "inheritance, legacy," from L. hereditatem (nominative hereditas) "heirship, inheritance," → heritage.

Rigandâšt, literally "possessing heritage," from rigan, → heritage, + dâšt past stem of dâštan "to have, hold, possess, maintain," → property.

  ریگن‌بردنی، دریگیدنی   
riganbordani, darigidani

Fr.: dont on peut hériter, qui peut hériter   


inherit; → -able.


Fr.: héritage   

1) Something inherited at birth, such as personal characteristics, status, and possessions.
2) Anything that has been transmitted from the past or handed down by tradition (

M.E. from M.Fr., from O.Fr. iritage, eritage, heritage "heir; inheritance, ancestral estate, heirloom," from heriter "inherit," from L.L. hereditare, ultimately from L. heres (genitive heredis) "heir, heiress," from PIE root *ghe- "to be empty, left behind" (related Gk. word khera "widow").

Rigan from rig "left, abandoned" (in mordé rig "heritage, effects of a dead person, anything hereditary, heirloom") + noun suffix -an (as in rowzan, rowšan, suzan, rasan, zaqan, hâvan, etc.); ultimately from Proto-Ir. *raic- "to leave, abandon;" cf. Av. raēc- "to leave, let;" Mid.Pers. (+ *pati-) phryz-, Mod.Pers. parhêz, parhiz "to keep away from, abstain, avoid;" Khotanese (+ *fra-) hars- "to be left, remain;" Mod.Pers. rištan "to set at liberty, absolve;" Mid.Pers. (+ *ui-) wirēz-, Mod.Pers. gurēz, goriz, gurēxtan, gorixtan "to flee, run away;" Gk. leipein "to leave;" L. linquere "to leave;" PIE *leikw- "to leave, let" (Cheung 2006).


Fr.: herméneutique   

Of or related to hermeneutics, interpretative; explanatory. Also hermeneutical.



Fr.: herméneutique   

The science or art of → interpretation. Originally the term was limited to the interpretation of the Scriptures, but since the nineteenth century it has developed into a general theory of human understanding through the work of Friedrich Schleiermacher (1768-1834), Wilhelm Dilthey (1833-1911), and others. The comprehension of any written text requires hermeneutics. Many different hermeneutic theorists have proposed many different methodologies.

From Gk. hermeneutikos "interpreting," from hermeneutes "interpreter," from hermeneuein "to interpret," of unknown origin. It was formerly thought to derive from Hermes, the tutelary divinity of speech, writing, and eloquence.

Âzand-pardâzik, from âzand, → interpretation, + pardâz, present stem of pardâxtan "to accomplish, bring to perfection; to care," → theoretician, + -ik, → ics.


Fr.: herméneutiste   

Someone who interprets literary or scriptural texts.

Agent noun from → hermeneutics

Hermitian conjugate
  همیوغ ِ اِرمیتی   
hamyuq-e Hermiti

Fr.: conjugé hermitien   

Math.: The Hermitian conjugate of an m by n matrix A is the n by m matrix A* obtained from A by taking the → transpose and then taking the complex conjugate of each entry. Also called adjoint matrix, conjugate transpose. → Hermitian operator.

Hermitian, named in honor of the Fr. mathematician Charles Hermite (1822-1901), who made important contributions to number theory, quadratic forms, invariant theory, orthogonal polynomials, elliptic functions, and algebra. One of his students was Henri Poincaré; → conjugate.

Hermitian operator
  آپارگر ِ اِرمیتی   
âpârgar-e Hermiti

Fr.: opérateur hermitien   

An operator A that satisfies the relation A = A*, where A* is the adjoint of A. → Hermitian conjugate.

Hermitian conjugate; → operator.


Fr.: Herschel   

Sir William Herschel (1738-1822), German-born English astronomer, the discoverer of the → infrared radiation and planet → Uranus.
Herschelian telescope, → Herschel Satellite

Herschel Satellite
  ماهواره‌ی ِ هرشل   
mâhvâre-ye Herschel

Fr.: Satellite Herschel   

A European Space Agency (ESA) mission to perform imaging photometry and spectroscopy in the → far infrared and → submillimeter regions of the electromagnetic spectrum, covering approximately the 55-672 µm range. In fact Herschel is the first space facility dedicated to these wavelength ranges. It carries a 3.5 m diameter passively cooled mirror. The science payload complement - two cameras/medium resolution spectrometers (PACS and SPIRE) and a very high resolution → superheterodyne spectrometer (HIFI) - are housed in a superfluid helium cryostat. Herschel was launched on 14 May 2009, together with the → Planck Satellite. Its observing position lies at the L2 → Lagrangian point, some 1.5 million km from Earth. Herschel is designed, among other things, to study the formation of galaxies in the early Universe, and to investigate the formation of stars and their interaction with the → interstellar medium.

Herschel; → satellite.

Herschelian telescope
  تلسکوپ ِ هرشل، دوربین ~   
teleskop-e Herschel, durbin-e ~

Fr.: télescope de Herschel   

A → reflecting telescope in which the → primary mirror is tilted so that light is focused near one side of the open end of the tube. The → eyepiece then picks up this light directly, avoiding light loss from reflection by a → secondary mirror. The drawback is → astigmatism, unless the → focal ratio is large. Herschel used this design in his giant 48-inch instrument.

Herschel; → telescope.

hertz (Hz)
hertz (#)

Fr.: hertz   

The SI unit of frequency, defined as a frequency of 1 cycle per second.

After Heinrich Rudolf Hertz (1857-1894), the German physicist, who made several important contributions to the study of electromagnetism.

Hertz experiment
  آزمایش ِ هرتز   
âzmâyeš-e Hertz (#)

Fr.: expérience de Hertz   

A laboratory experiment carried out by Heinrich Hertz in 1888 to generate and detect → electromagnetic waves for the first time. It involved a high voltage power source, consisting of two → capacitors, each provided with a conducting rod. The rods were separated by a small → spark gap and connected to an → induction coil. When the electrodes were raised to a sufficiently high → potential difference, a spark passed across the gap, and an oscillating discharge took place. A group of waves with a wavelength of a few meters were emitted at each discharge. A wire loop provided with a detecting spark gap, held away from the oscillating sparks, produced sparks upon arrival of the oscillating electric and magnetic fields.

hertz (Hz); → experiment.

hertz to meter conversion
  هاگرد ِ هرتز به متر   
hâgard-e hertz bé metr

Fr.: conversion hertz / mètre   

frequency to wavelength conversion.

hertz; → meter; → conversion.

Hertzian oscillator
  نوشگر ِ هرتزی   
navešgar-e Hertzi

Fr.: oscillateur hertzien   

An electrical system used for the production of → electromagnetic waves. It consists of two equal → capacitors connected to two electrodes with a → spark gap between the electrodes. The system is connected to an → induction coil. When the induction coil is activated, electromagnetic waves are generated across the spark gap. See also → Hertz experiment.

hertz (Hz); → oscillator.

Hertzsprung gap
  گاف ِ هرتسپرونگ   
gâf-e Hertzsprung

Fr.: trou de Hertzsprung   

A region of the → Hertzsprung-Russell diagram, between the → main sequence and the → giant branch, occupied by very few stars. It corresponds to a very short period in stellar evolution.

Named after the Danish astronomer Ejnar Hertzsprung (1873-1967), who first noticed this phenomenon; → gap

Hertzsprung-Russell diagram
  نمودار ِ هرتسپرونگ-راسل   
nemudâr-e Hertzsprung-Russell (#)

Fr.: diagramme de Hertzsprung-Russell   

A display of stellar properties using a plot of → effective temperature (or instead → color or → spectral type) along the abscissa versus → luminosity (or → absolute magnitude). The temperature is plotted in the inverse direction, with high temperatures on the left and low temperatures on the right. On the diagram the majority of stars are concentrated in a diagonal strip running from upper left to lower right, i.e. from high temperature-high luminosity → massive stars to low temperature-low luminosity → low-mass stars. This feature is known as the → main sequence. This is the locus of stars burning hydrogen in their cores (→ proton-proton chain). The lower edge of this strip, known as the → zero age main sequence (ZAMS), designates the positions where stars of different mass first begin to burn hydrogen in their cores. Well below the main sequence there is a group of stars that, despite being very hot, are so small that their luminosity is very small as a consequence. These are the class of → white dwarfs. These objects represent old and very evolved stars that have shed their outer layers to reveal a very small but extremely hot inner core. They are no longer generating energy but are merely emitting light as they cool (→ white dwarf cooling track). Stars with high luminosities but relatively low temperatures occupy a wide region above the main sequence. The majority of them have used up all the hydrogen in their cores and have expanded and cooled as a result of internal readjustment. Called → red giants, they are still burning helium in their cores (→ helium burning, → carbon burning). There are also stars with very high luminosities, resulting from their enormous outputs of energy, because they are burning their fuel at a prodigious rate. These are the → supergiants. They can be hot or cool, hence blue or red in color. Same as → H-R diagram.
See also:
asymptotic giant branch, → blue horizontal branch star, → extreme horizontal branch star, → field horizontal branch star, → Hayashi track, → horizontal branch, → post-asymptotic giant branch star, → red giant branch, → supra-horizontal branch star, → zero age horizontal branch star, → Humphreys-Davidson limit.

Named after the Danish Ejnar Hertzsprung (1873-1967) and the American Henry Norris Russell (1877-1957). However, the first H-R diagram was published not by Hertzpurung neither Russell, but by a PhD student of Karl Schwarzschild at Göttingen. The student was Hans Rosenberg (1879-1940), who in 1910 published the diagram for stars in the → Pleiades (Astronomische Nachrichten, Vol. 186 (4445), p. 71, 1910). Although Hertzpurung had a very preliminary diagram in 1908, his first proper diagram was published in 1911. Likewise, Russell published his version only in 1915 with the better and more numerous data then available (Nielsen, A.V., 1969, Centaurus 9, 219; Valls-Gabaud, D., 2002, Observed HR diagrams and stellar evolution, ASP Conf. Proceedings, Vol. 274. Edited by Thibault Lejeune and João Fernandes); → diagram.

Hesperian era
  دوران ِ هسپریسی   
dowrân-e hesperisi

Fr.: ère hespérienne   

The Martian geologic era after the Noachian Era which lasted from about 3500 million to 2500 million years ago. During this period Martian climate began to change to drier, dustier conditions. Water that flowed on the Martian surface during the Noachian Era may have frozen as underground ice deposits, and most river channels probably experienced their final flow episodes during this era. → Noachian era; → Amazonian era.

Named after the Martian plains of Hesperis; → era.

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