An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 481
Hubble-Lemaitre flow
  تچان ِ هابل-لومتر   
tacân-e Hubble-Lemaître

Fr.: flot de Hubble-Lemaître   

The general outward motion of → galaxy clusters resulting from the → expansion of the Universe.

Hubble-Lemaitre law; → flow.

Hubble-Lemaitre law
  قانون ِ هابل-لومتر   
qânun-e Hubble-Lamaître

Fr.: loi de Hubble-Lemaître   

The speed with which a → galaxy cluster recedes from us is directly proportional to its distance. It can be stated as v = H0d, where v is the recessional velocity, H0 the → Hubble-Lamaitre constant, and d the distance. See also → Hubble-Lemaitre flow. It should be underlined that Hubble was not the first to discover the → velocity-distance relation. Two years before Hubble, in 1927, Georges Lemaître (1894-1966) had derived the relation and published it in a paper in French which remained neglected (→ Friedmann-Lemaitre Universe).

The International Astronomical Union (IAU) at its 30th Meeting approved the Resolution B4 proposed by the IAU Executive Committee recommending the use of Hubble-Lemaitre law instead of Hubble's law, after Edwin Hubble (1889-1953), the American astronomer who published his results in 1929 and Georges Lemaître, Belgian priest and astronomer, who published a paper on the expansion of the Universe in 1927; → law.

Hubble-Lemaitre parameter
  پارامون ِ هابل-لومتر   
pârânmun-e Hubble-Lemaître

Fr.: paramètre de Hubble-Lemaître   

The rate pf change of the → cosmic scale factor: H(t) = (dR/dt)/R. The Hubble parameter is a time-dependent quantity and therefore is not constant. The → Hubble-Lemaitre constant is the Hubble-Lemaître parameter measured today.

Hubble-Lemaitre law; → parameter.

Hubble-Lemaitre tension
  تنش ِ پایای ِ هابل-لومتر   
taneš-e pâyâ-ye Hubble-Lemaître

Fr.: Tension sur la constante de Hubble-Lemaître   

The discrepancy between the value of the → Hubble-Lemaitre constant inferred from a ΛCDM fit (→ Lambda cold dark matter model) to the → cosmic microwave background (CMB) and local measurements. The Universe appears to be expanding much faster now than predicted even with our latest understanding of its initial conditions and contents. Based on the → Hubble Space Telescope observations, the Hubble-Lemaitre constant is very recently estimated to be 74.03 km s-1 Mpc-1. This value indicates that the Universe is expanding at a rate about 9% faster than that implied by the → Planck satellite's observations of the → early Universe, which give a value for the Hubble constant of 67.4 km s-1 Mpc-1. For discussion, see D'Arcy Kenworthy et al. (2019, ApJ 875, 145).

Hubble-Lamaitre constant; → tension.

Hubble-Sandage classification
  رده‌بندی ِ هابل-سندیج   
radebandi-ye Hubble-Sandage

Fr.: classification de Hubble-Sandage   

Same as the → Hubble classification.

Hubble; → Hubble-Sandage variable; → sequence.

Hubble-Sandage variable
  ورتنده‌ی ِ هابل-سندیج   
vartande-ye Hubble-Sandage

Fr.: variable de Hubble-Sandage   

A type of highly luminous → blue supergiant star with variable light, first discovered in the M31 and M33 galaxies; also called → S Doradus stars. They are now believed to be part of the class of → Luminous Blue Variable stars.

Hubble; Allan Rex Sandage (1926-2010), American cosmologist.

Huge Hole
  سوراخ ِ کلان   
surâx-e kalân

Fr.: Trou Géant   

A region of the Universe, nearly a billion light-years across, mostly devoid of stars, gas, other normal matter, and also → dark matter. Situated at about 6 billion light-years from us, in projection on the the constellation → Eridanus, it shows up as a particularly cold region in the map of the → cosmic microwave background (CMB) radiation. Observations made using the → Very Large Array (VLA) radio telescope show a relative absence of matter in that area.

Huge, from M.E. huge, hoge, from O.F. ahuge, ahoge "enormous," from a variant of → ad- + hoge "height," → high; → hole.

Surâx, → hole; kalân "great, large, bulky."

Huggins band
  باند ِ هاگینس   
bând-e Huggins

Fr.: bande de Huggins   

A band in the → absorption spectrum of → ozone (O3) extending in the → ultraviolet from 310 nm to 370 nm. It is located at the red end of the strong → Hartley band.

W. Huggins and M. Huggins, Proc. R. Soc. London 48, 216 (1890).

Hugoniot curve
  خم ِ هوگونیو   
xam-e Hugoniot

Fr.: courbe de Hugoniot   

A curve, on the pressure versus specific volume plane, representing the locus of all the possible states that can be reached by a substance immediately after the passage of a single → shock wave. For each initial condition there is a different curve. No combustion occurs in the process and, therefore, the chemical composition of the medium does not change. See also → Rayleigh line; → Crussard curve.

Named after the French physicist Pierre Henri Hugoniot (1851-1887), who worked on fluid mechanics, especially flow properties before and after shock waves; → curve.

Hulse-Taylor pulsar (PSR 1913+16)
  تپار ِ هالس-تیلر، پولسار ِ ~   
tapâr-e Hulse-Taylor, pulsâr-e ~

Fr.: pulsar de Hulse-Taylor   

A → pulsar with a period of 59 milliseconds (17 pulses per second) moving around a compact companion in an elongated orbit (period 7.75 hours). It is thought that the companion is probably also a → neutron star with the same mass as the pulsar (1.4 solar masses). The orbit is gradually shrinking because of → gravitational radiation, as predicted by the theory of → general relativity. See also → binary pulsar, → millisecond pulsar.

Named after the American physicists Russell Hulse and Joseph Taylor of Princeton University, who discovered the pulsar in 1974, for which they shared the 1993 Nobel prize in physics; → pulsar.

  ۱) مرتوگان؛ ۲) مرتو   
1) martugân; 2) martu

Fr.: humain   

1) (adj.) Belonging or pertaining to or of the nature of man or mankind, contrasted with animals.
2) (n.) A human being, → man. See also → anthropo-.

M.E. from M.F. humain, from L. humanus "of man, human," also "humane, kind, gentle, polite," probably related to homo "man," and to humus "earth," on notion of "earthly beings."

Martu, → man, + -gân a suffix forming nouns or adjectives denoting relation and plurality.


Fr.: humanisme   

1) Any system or mode of thought or action in which human interests, values, and dignity predominate (
2) Philo.: A variety of ethical theory and practice that emphasizes reason, scientific inquiry, and human fulfillment in the natural world and often rejects the importance of belief in God (

human + → -ism.


Fr.: humaniste   

A person having a strong interest in or concern for human welfare, values, and dignity (

human + → -ist.

  مرتوگان‌دوست؛ مرتوگان‌دوستانه   
martugândust, martugândustâné

Fr.: humanitaire   

Having concern for or helping to improve the welfare and happiness of people (

humanity + -arian a suffix forming nouns and adjectives, from -ari(us) or -ary + -an.

Martugândust, literally "friend/lover of humanity," from martugân, → humanity, + dust "friend," Mid.Pers. dôst "friend," dôšidan "to love, like, choose;" O.Pers. dauštā- "friend;" Av. zuš- "to take pleasure;" PIE root *geus- "to taste, like, choose;" cf. Skt. jos- "to like, enjoy;" Gk. geuomai, L. gustus "taste, enjoyment" (Cheung 2007).


Fr.: humanités   

The study of classical languages and classical literature.

Plural of → humanity.

Martugânik, from martugân, → human, + → -ik, → -ics.

  ۱) مرتوگان؛ ۲) مرتوگانی   
1) martugân; 2) martugâni

Fr.: humanité   

1) All human beings collectively; the human race; humankind.
2) The quality of being human; human nature.

human + → -ity.


Fr.: humaniser   

1) To render humane, kind, or gentle.
2) To make human.

human; → -ize.

Humboldt current
  جریان ِ هومبولت   
jarayân-e Humboldt (#)

Fr.: courant de Humboldt   

A cold ocean current that flows northward along the western side of South America, offshore Chile and Peru. Dominate weather in this area includes coastal fog and low clouds. The presence or lack of this current is a vital part of the weather pattern known as El Niño.

Named after the German naturalist and explorer Alexander von Humboldt (1769-1859). → current.

  نمناک، نمور   
namnâk (#), namur (#)

Fr.: humide   

Containing or characterized by a high amount of water or water vapor; moist. → humidity.

Adj. of → humidity.

Namnâk, namur, from nam, → humidity + adj. suffixes -nâk and -ur, variant -var (Mid.Pers. -uwar, -war, from O.Pers. -bara, from bar- "to bear, carry"), as in ranjur, ganjur, dastur.

nam (#)

Fr.: humidité   

Generally, a measure of the water vapor content of the air. Popularly, it is used synonymously with → relative humidity. → absolute humidity, → dew point, → mixing ratio, → specific humidity.

Humidity, from O.Fr. humide, from L. humidus "moist, wet," variant (by influence of humus "earth") of umidus, from umere "be moist."

Nam "humidity, moisture," from Mid.Pers. nam, namb "moisture;" Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" cf. Skt. nábhas- "moisture, cloud, mist;" Gk. nephos "cloud, mass of clouds," nephele "cloud;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" from PIE *nebh- "cloud, vapor, fog, moist, sky."

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