An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 35 Search : newton
MOdified Newtonian Dynamics (MOND)
  توانیک ِ نیوتنی ِ واترزیده   
tavânik-e niyutoni-ye vâtarzidé

Fr.: dynamique newtonienne modifiée   

A modification of the Newton's law of gravitation below a critical acceleration of about 1.2 x 10-8 cm s-2, where the gravitational force scales as 1/r instead of 1/r2. Originally put forward to describe the rotation curves of galaxies with no need to assume any dark matter, MOND is now tested at larger cosmological scales (Milgrom, M. 1983, ApJ, 270, 365).

modify; → Newtonian dynamics.

newton (#)

Fr.: newton   

The unit of force in the SI system of units. 1 newton (N) is defined as the force required to give a mass of 1 kilogram an acceleration of 1 m s-2. 1 N = 105  → dynes.

Named after Sir Isaac Newton (1642-1727), the English highly prominent physicist and mathematician.

Newton constant
  پایای ِ نیوتن   
pâyâ-ye Newton

Fr.: constante de Newton   

Same as the → gravitational constant.

Newton; → constant.

Newton's color wheel
  چرخ ِ رنگ ِ نیوتن   
carx-e rang-e Newton

Fr.: disque de Newton   

The arrangement of the seven colors of the rainbow on a disk. When the disk rotates very fast, the eye cannot distinguish between individual colors and the disk is perceived as white. This apparatus demonstrates the discovery made by Newton (Opticks, 1704) that light is composed of seven colors.

Newton; → color; → wheel.

Newton's constant
  پایای ِ نیوتون   
pâyâ-ye Newton

Fr.: constante de Newton   

Same as the → gravitational constant.

Newton; → constant.

Newton's cradle
  گهواره‌ی ِ نیوتون   
gahvâre-ye Newton

Fr.: pendule de Newton   

A device consisting of a series of equal → pendulums in a row used to demonstrate the laws of → conservation of momentum and → conservation of energy.

Newton; → cradle.

Newton's disk
  گرده‌ی ِ نیوتن   
gerde-ye Newton

Fr.: disque de Newton   

Newton's color wheel.

Newton; → disk.

Newton's equation
  هموگش ِ نیوتن   
hamugeš-e Newton

Fr.: équation de Newton   

In → geometric optics, an expression relating the → focal lengths of an → optical system (f and f') and the object x and image x' distances measured from the respective focal points. Thus, ff' = xx'. Same as Newton's formula.

Newton; → equation.

Newton's first law of motion
  نخستین قانون ِ نیوتنی ِ جنبش   
naxostin qânun-e Newtoni-ye jonbeš (#)

Fr.: première loi newtonienne de mouvement   

A body continues in its state of constant velocity (which may be zero) unless it is acted upon by an external force.

Newton; → first; → law; → motion.

Newton's law of cooling
  قانون ِ سردش ِ نیوتن   
qânun-e sardeš-e Newton

Fr.: loi de refroidissement de Newton   

An approximate empirical relation between the rate of → heat transfer to or from an object and the temperature difference between the object and its surrounding environment. When the temperature difference is not too large: dT/dt = -k(T - Ts), where T is the temperature of the object, Ts is that of its surroundings, t is time, and k is a constant, different for different bodies.

Newton; → law; → cooling.

Newton's law of gravitation
  قانون ِ گرانش ِ نیوتن   
qânun-e gerâneš-e Newton

Fr.: loi newtonienne de la gravitation   

The universal law which states that the force of attraction between any two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them: F = G (m1.m2)/r2, where G is the → gravitational constant.

Newton; → law; → gravitation.

Newton's laws of motion
  قانونهای ِ جنبش ِ نیوتون   
qânunhâ-ye jonbeš-e Newton

Fr.: lois de mouvement de Newton   

The three fundamental laws which are the basis of → Newtonian mechanics. They were stated in Newton's Principia (1687). → Newton's first law, → Newton's second law , → Newton's third law.

Newton; → law; → motion.

Newton's method
  روش ِ نیوتن   
raveš-e Newton

Fr.: méthode de Newton   

Same as the → Newton-Raphson method.

Newton; → method.

Newton's rings
  حلقه‌های ِ نیوتن   
halqehâ-ye Newton (#)

Fr.: anneaux de Newton   

Colored circular → fringes formed when light beams reflected from two polished, adjacent surfaces, placed together with a thin film of air between them, interfere. → interference.

Newton; → ring.

Newton's second law of motion
  دومین قانون ِ نیوتنی ِ جنبش   
dovomin qânun-e Newtoni-ye jonbeš (#)

Fr.: seconde loi newtonienne de mouvement   

For an unbalanced force acting on a body, the acceleration produced is proportional to the force impressed; the constant of proportionality is the inertial mass of the body.

Newton; → second; → law; → motion.

Newton's shell theorem
  فربین ِ پوسته‌ی ِ نیوتن   
farbin-e puste-ye Newton

Fr.: théorème de Newton   

In classical mechanics, an analytical method applied to a material sphere to determine the gravitational field at a point outside or inside the sphere. Newton's shell theorem states that: 1) The gravitational field outside a uniform spherical shell (i.e. a hollow ball) is the same as if the entire mass of the shell is concentrated at the center of the sphere. 2) The gravitational field inside the spherical shell is zero, regardless of the location within the shell. 3) Inside a solid sphere of constant density, the gravitational force varies linearly with distance from the center, being zero at the center of mass. For the relativistic generalization of this theorem, see → Birkhoff's theorem.

Newton; → shell; → theorem.

Newton's third law of motion
  سومین قانون ِ نیوتنی ِ جنبش   
sevomin qânun-e Newtoni-ye jonbeš (#)

Fr.: troisième loi newtonienne de mouvement   

In a system where no external forces are present, every action force is always opposed by an equal and opposite reaction.

Newton; → third; → law; → motion.

Newton-Leibniz formula
  دیسول ِ نیوتن-لایبنیتس   
disul-e Newton-Leibniz

Fr.: formule de Newton-Leibniz   

The formula expressing the value of a → definite integral of a given function over an interval as the difference of the values at the end points of the interval of any → antiderivative of the function: ∫f(x)dx = F(b) - F(a), summed from x = a to x = b.

Named after Isaac → Newton and Gottfried Wilhelm Leibniz (1646-1716), who both knew the rule, although it was published later; → formula.

Newton-Maxwell incompatibility
  ناسازگاری ِ نیوتن-ماکسول   
nâsâzgâri-ye Newton-Maxwell

Fr.: incompatibilité entre Newton et Maxwell   

The incompatibility between → Galilean relativity and Mawxell's theory of → electromagnetism. Maxwell demonstrated that electrical and magnetic fields propagate as waves in space. The propagation speed of these waves in a vacuum is given by the expression c = (ε00)-0.5, where ε0 is the electric → permittivity and μ0 is the magnetic → permeability, both → physical constants. Maxwell noticed that this value corresponds exactly to the → speed of light in vacuum. This implies, however, that the speed of light must also be a universal constant, just as are the electrical and the magnetic field constants! The problem is that → Maxwell's equations do not relate this velocity to an absolute background and specify no → reference frame against which it is measured. If we accept that the principle of relativity not only applies to mechanics, then it must also be true that Maxwell's equations apply in any → inertial frame, with the same values for the universal constants. Therefore, the speed of light should be independent of the movement of its source. This, however, contradicts the vector addition of velocities, which is a verified principle within → Newtonian mechanics. Einstein was bold enough to conclude that the principle of Newtonian relativity and Maxwell's theory of electromagnetism are incompatible! In other words, the → Galilean transformation and the → Newtonian relativity principle based on this transformation were wrong. There exists, therefore, a new relativity principle, → Einsteinian relativity, for both mechanics and electrodynamics that is based on the → Lorentz transformation.

Newton; → Maxwell; → incompatibility.

Newton-Raphson method
  روش ِ نیوتن-رفسون   
raveš-e Newton-Raphson

Fr.: méthode de Newton-Raphson   

A method for finding roots of a → polynomial that makes explicit use of the → derivative of the function. It uses → iteration to continually improve the accuracy of the estimated root. If f(x) has a → simple root near xn then a closer estimate to the root is xn + 1 where xn + 1 = xn - f(xn)/f'(xn). The iteration begins with an initial estimate of the root, x0, and continues to find x1, x2, . . . until a suitably accurate estimate of the position of the root is obtained. Also called → Newton's method.

Newton found the method in 1671, but it was not actually published until 1736; Joseph Raphson (1648-1715), English mathematician, independently published the method in 1690.

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