An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < ano red > >>

Number of Results: 23 Search : shift
anomalous redshift
  سرخ-کیب ِ ناسان   
sorx-kib-e nâsân

Fr.: décalage anormal vers le rouge   

The high redshift of a quasar which is seemingly physically associated with a galaxy of low redshift.

anomalous; → redshift.


Fr.: décalage vers le bleu   

The apparent shift of the wavelength towards the shorter wavelength region of the radiation spectrum of an approaching object due to the Doppler effect.

blue; → shift.

blueshifted component
  همنه‌ی ِ آبی-کیب   
hamneye âbikib

Fr.: composante décalée vers le bleu   

A constituent of a composite astronomical object which has a motion directed towards the observer, as revealed by its spectrum.

blueshift; → component.

Compton shift
  کیبِ کامپتون   
kib-e Compton

Fr.: décalage de Compton   

Of the → Compton effect, the amount of increase in the wavelength of an energetic photon upon its collision with an electron.

Compton; → shift.

cosmological redshift
  سرخ کیب ِ کیهان‌شناسیک، ~ کیهان‌شناختی   
sorxkib-e keyhânšenâsik, ~ keyhânšenâxti

Fr.: décalage vers le rouge cosmologique, redshift ~   

The → redshift of a remote object (galaxy, quasar, supenova) due to the expansion of the Universe.

cosmological; → redshift.

Doppler shift
  کیب ِ دوپلر   
kib-e Doppler

Fr.: décalage Doppler   

Effect of the relative motion of a wave source (light, sound) and the observer. If the source is moving away, the wavelength is stretched (shifted toward lower frequencies). If the source is approaching, the wavelength is compressed (shifted toward higher frequencies). These effects, known as Doppler shifts, are in the case of light waves called redshift and blueshift, respectively.

Doppler effect; → shift.

frequency shift
  کیب ِ بسامد   
kib-e basâmad

Fr.: décalage de fréquence   

The change in the frequency of a wave motion due to the → Doppler effect.

frequency; → shift.

gravitational redshift
  سرخ‌کیب ِ گرانشی   
sorxkib-e gerâneši

Fr.: décalage vers le rouge gravitationnel   

The change in the wavelength or frequency of electromagnetic radiation in a gravitational field predicted by general relativity.

gravitational; → redshift.

high redshift object
  بر‌آخت ِ مه-سرخ‌کیب   
barâxt-e meh-sorxkib

Fr.: objet à grand décalage vers le rouge   

A galaxy or quasar having a → redshift larger than about 0.8, corresponding to a → look-back time half the present age of the Universe. The qualifier "high" is, however, relative and depends on context and authors' assessment.

high; → redshift; → object.

isotope shift
  کیب ِ ایزوتوپی   
kib-e izotopi

Fr.: décalage isotopique   

A displacement in the spectral lines due to the different isotopes of an element.

isotope; → shift.

Lamb shift
  کیب ِ لمب   
kib-e Lamb

Fr.: décalage de Lamb   

A tiny change in the → energy levels of the → hydrogen atom between the states 2S1/2 and 2P1/2, which creates a shift in the corresponding → spectral lines. The 2P1/2 state is slightly lower than the 2S1/2 state, contrarily to the Schrodinger's solution. The difference is explained by the interaction between → vacuum energy fluctuations and the hydrogen electron in different orbitals.

Named after Willis Eugene Lamb, Jr. (1913-2008), an American physicist who discovered this effect in 1951, and won the Nobel Prize in physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum;" → shift.

low redshift
keh sorxkib

Fr.: faible décalage vers le rouge   

A redshift characterizing a near-by receding object.

low; → redshift.

mass shift
  کیب ِ جرمی   
kib-e jermi


The portion of the isotope shift which results from the difference between the nuclear masses of different isotopes.

mass; → shift.

paradigm shift
  کیب ِ پرادیش، دگرگونی ِ ~   
kib-e parâdiš, degarguni-ye ~

Fr.: changement de paradigme   

1) Philosophy of science: A process of revolutionary change in scientific → paradigms, whereby established scientific ideas are replaced by new ones. For instance, Copernicus' evidence that the Earth revolved around the Sun caused a paradigm shift in astronomy.
2) The idea of paradigm shift has been transferred from the sciences to other areas of society and culture, referring to a fundamental reorganization of how people think about an entire topic.

paradigm; → shift; → change.

phase shift
  کیب ِ فاز   
kib-e fâz

Fr.: décalage de phase   

Any change in the phase of a periodic quantity or in the phase difference between two or more periodic quantities.

phase; → shift.


Fr.: décalage vers le rouge   

A shift in the lines of an object's spectrum toward longer wavelengths. Redshift indicates that an object is moving away from the observer. The larger the redshift, the faster the object is moving. Redshift is expressed by z = Δλ/λ = v/c, where λ is the wavelength, Δλ the wavelength shift, v the velocity of the source relative to the observer, and c the → speed of light. When v approaches c, redshift is expressed by the → relativistic formula z = ((1 +v/c)/(1 - v/c))½ - 1.

red; → shift.

redshift space
  فضای ِ سرخ-کیب   
fazâ-ye sorx-kib

Fr.: espace de décalage vers le rouge   

The space corresponding to → redshift measurements, as contrasted with real space. See also → redshift space distortion

redshift; → space.

redshift space distortion
  چولگی ِ فضای ِ سرخ-کیب   
cowlegi-ye fazâ-ye sorx-kib

Fr.: distorsion dûe aux vitesses particulières sur la ligne de visée   

The distortion observed in → redshift space of → galaxy clusters caused by peculiar velocities of the members (→ peculiar velocity). In a perfectly homogeneous → Friedmann-Lemaitre Universe the redshifts would accurately measure radial distances from the observer, and the mapping from real space to redshift space would simply be an identity. In an inhomogeneous Universe the peculiar velocities associated with any inhomogeneous structure will introduce a distortion in this mapping (N. Kaiser, 1987, MNRAS 227, 1). See also: → fingers of God, → Kaiser effect.

redshift; → space; → distortion;.

redshift survey
  بردید ِ سرخ‌کیب   
bardid-e sorx kib

Fr.: relevé de décalages vers le rouge   

A survey of a large region of the sky to measure the redshifts of all the galaxies down to a certain limiting magnitude.

redshift; → survey.

redshift-distance relation
  بازانش ِ سرخ‌کیب-دورا   
bâzâneš-e sorxkib-durâ

Fr.: relation décalage vers le rouge-distance   

The correlation, first established by E. Hubble, between the cosmological recession velocities of galaxies and their distances.

redshift; → distance; → relation.

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