An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 12 Search : relativity
Einsteinian relativity
  بازانیگی ِ اینشتینی   
bâzânigi-ye Einsteini

Fr.: relativité einsteinienne   

The laws of physics are the same in all → inertial reference frames and are invariant under the → Lorentz transformation. The → speed of light is a → physical constant, i.e. it is the same for all observers in uniform motion. Einsteinian relativity is prompted by the → Newton-Maxwell incompatibility. See also: → Galilean relativity, → Newtonian relativity.

Einstein; → relativity.

Galilean relativity
  بازانیگی ِ گالیله‌ای   
bâzânigi-ye Gâlile-yi

Fr.: relativité galiléenne   

The principle according to which the fundamental laws of physics are the same in all frames of reference moving with constant velocity with respect to one another (→ inertial reference frames). Same as → Galilean invariance and → Newtonian relativity.
See also: → Galilean transformation, → Einsteinian relativity.

After Galileo Galilei (1564-1642), the Italian physicist and astronomer, who first described this principle in 1632; → relativity.

general relativity
  بازانیگی ِ هروین   
bâzânigi-ye harvin

Fr.: relativité générale   

The theory of → gravitation developed by Albert Einstein (1916) that describes the gravitation as the → space-time curvature caused by the presence of matter or energy. Mass creates a → gravitational field which distorts the space and changes the flow of time. In other words, mass causes a deviation of the → metric of space-time continuum from that of the "flat" space-time structure described by the → Euclidean geometry and treated in → special relativity. General relativity developed from the → principle of equivalence between gravitational and inertial forces. According to general relativity, photons follow a curved path in a gravitational field. This prediction was confirmed by the measurements of star positions near the solar limb during the total eclipse of 1919. The same effect is seen in the delay of radio signals coming from distant space probes when grazing the Sun's surface. Moreover, the space curvature caused by the Sun makes the → perihelion of Mercury's orbit advance by 43'' per century more than that predicted by Newton's theory of gravitation. The → perihelion advance can reach several degrees per year for → binary pulsar orbits. Another effect predicted by general relativity is the → gravitational reddening. This effect is verified in the → redshift of spectral lines in the solar spectrum and, even more obviously, in → white dwarfs. Other predictions of the theory include → gravitational lensing, → gravitational waves, and the invariance of Newton's → gravitational constant.

general; → relativity.

Newtonian principle of relativity
  پروز ِ بازانیگی ِ نیوتن   
parvaz-e bâzânigi-ye Newton

Fr.: principe de relativité de Newton   

The Newton's equations of motion, if they hold in any → reference frame, they are valid also in any other reference frame moving with uniform velocity relative to the first.

Newtonian; → principle; → relativity.

Newtonian relativity
  بازانیگی ِ نیوتنی   
bâzânigi-ye Newtoni

Fr.: relativité newtonienne   

The laws of physics are unchanged under → Galilean transformation. This implies that no mechanical experiment can detect any intrinsic diff between two → inertial frames. Same as → Galilean relativity.

Newton; → relativity.

principle of relativity
  پروز ِ بازانیگی   
parvaz-e bâzânigi

Fr.: principe de relativité   

The first postulate in Einstein's theory of → special relativity whereby all the laws of physics are the same in every → inertial reference frame. In other words, no physical measurement can distinguish one inertial reference frame from another. See also → principle of constancy.

principle; → relativity.

relativity
  بازانیگی   
bâzânigi

Fr.: relativité   

General: The state or fact of being relative.
Physics: 1) Short for the → Galilean relativity.
2) Short for the → relativity theory of Einstein.

Relativity, from → relative + → -ity.

relativity of simultaneity
  بازانیگی ِ همزمانی   
bâzânigi-ye hamzamâni

Fr.: relatitivité de simultanéité   

A basic concept of → special relativity whereby → events that are simultaneous in one → reference frame are not simultaneous in another reference frame moving with respect to the first.

relativity; → simultaneity.

relativity principle
  پروز ِ بازانیگی   
parvaz-e bâzânigi

Fr.: principe de relativité   

The requirement employed by Einstein in his relativity theories, that the equations describing the laws of physics are the same in all frames of reference. This statement and that of the constancy of the speed of light constitute the founding principles of special relativity.

Relativity; → principle.

relativity theory
  نگره‌ی ِ بازانیگی   
negare-ye bâzânigi

Fr.: théorie de la relativité   

The → theory of relativity.

theory; → relativity.

special relativity
  بازانیگی ِ ویژه   
bâzanigi-ye vižé

Fr.: relativité restreinte   

The theory formulated by A. Einstein in 1905, which is based on the following two → postulates:
1) → Principle of relativity: The laws of physical phenomena are the same when studied in terms of two reference systems moving at a constant velocity relative to each other.
2) → Principle of constancy: The → velocity of light in free space is the same for all observers and is independent of the relative velocity of the source of light and the observer.
The term "special theory of relativity" refers to the restriction in the first postulate to reference systems moving at a constant velocity relative to each other (→ inertial reference frame). See also → general relativity.

special; → relativity.

theory of relativity
  نگره‌ی ِ بازانیگی   
negare-ye bâzânigi

Fr.: théorie de la relativité   

Any of the two theories put forward by Albert Einstein: → special relativity (1905) and → general relativity (1916).

theory; → relativity;