qânun-e Hubble (#)
Fr.: loi de Hubble
The speed with which a galaxy recedes from us is directly proportional to its distance. Hubble's "law" is only statistically correct, as individual galaxies can have quite large random velocities around this overall → Hubble 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).
After Edwin Hubble (1889-1953), the American astronomer who published his results in 1929; → law.
Fr.: classification de Hubble-Sandage
Same as the → Hubble classification.
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.
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.
Surâx, → hole; kalân "great, large, bulky."
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)
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.
1) martugân; 2) martu
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.
1) Any system or mode of thought or action in which human interests, values, and dignity
A person having a strong interest in or concern for human welfare, values, and dignity (dictionary.com).
Having concern for or helping to improve the welfare and happiness of people (dictionary.com).
→ 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).
The study of classical languages and classical literature.
Plural of → humanity.
1) martugân; 2) martugâni
1) All human beings collectively; the human race; humankind.
1) To render humane, kind, or gentle.
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.
namnâk (#), namur (#)
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.
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."
Fr.: série de Humphreys
A series of → spectral lines in the → infrared spectrum of → neutral hydrogen emitted by electrons in → excited states transitioning to the level described by the → principal quantum number n = 6. It begins at 12368 nm (Hu α 12.37 microns) and has been traced to 3281.4 nm (3.28 microns).
Named after Curtis J. Humphreys (1898-1986), American physicist; → series.
Fr.: limite de Humphreys-Davidson
An empirical upper → luminosity boundary in the → H-R diagram. It consists of two sections, a sloping part and a horizontal part. The sloping part, which decreases with decreasing → effective temperature, corresponds roughly to the → Eddington limit. The horizontal part is the temperature-independent upper luminosity limit for late-type → hypergiants. It is thought that → massive stars above the Humphreys-Davidson limit encounter an → instability, possibly due to the opacity-modified Eddington limit, and experience high → mass loss episodes which prevent their evolution to cooler temperatures. → Luminous Blue Variable stars are examples of this high mass loss phase.
Named after Roberta M. Humphreys and Kris Davidson, who first dealt with this limit (1979, ApJ 232, 409); → limit.
Fr.: règle de Hund
An empirical rule stating that all orbitals of a given sublevel must be occupied by single electrons before pairing begins.
After the German physicist Friedrich Hund (1896-1997), known for his work on atoms and molecules. → rule.
The smallest three digit number in the decimal system and the smallest square of a two-digit number (10).
Hundred, from O.E. hundred "a counting of 100," from P.Gmc. *hunda- "hundred," as below, + *rath "reckoning, number."
Sad "hundred," from Mid.Pers. sad, sat, Av. sata- "hundred," satô.raocana- "with a hundred windows," satô.təmô.sata- "hundreds of hundred;" cf. Skt. śatá- "hundred;" Gk. hekaton; L. centum; Lith. simtas; P.Gmc. *hunda- "hundred" (Goth. hund; O.H.G. hunt); PIE *kmtom "hundred."