Big Bang singularity
takini-ye Big Bang
Fr.: singularité du Big Bang
A hypothetical state of → infinite energy density representing an infinite → gravitational field and infinite → space-time curvature. The singularity arises from using Einstein's theory of → general relativity concerning gravity. We know, however, that when the density and heat become extremely large, quantum physics of gravity becomes important. Yet Einstein's equations ignore quantum effects. In other words, in certain extreme conditions, Einstein's equations do not apply.
→ Big Bang; → singularity.
takini-ye âqâzin (#)
Fr.: singularité initiale
An instant of infinite density, infinite pressure, and infinite temperature where the equations of general relativity break down, if the standard Big Bang theory is extrapolated all the way back to time zero. → singularity.
→ initial; → singularity.
takini-ye berehné (#)
Fr.: singularité nue
A singularity that is not surrounded by an event horizon. It will therefore be visible and communicable to the outside world.
→ naked; → singularity.
Fr.: matrice non singulière
A → square matrix that is not a → singular matrix.
Fr.: singularité de Schwarzschild
A region of infinite → space-time curvature postulated to lie within a → black hole.
Math.: 1) Of or pertaining to a linear transformation from a vector space
to itself that is not one-to-one.
M.E., from O.Fr. singuler "single, separate," from L. singularis "single, solitary," from singulus "one, individual, separate," from sim- (stem of simplus) + diminutive suffix.
Takin, from tak "single, alone," related to tâq "odd, single," tâ, tâh "piece, part; fold, plait, ply;" Mid.Pers. tak "single," tâg, tâk, tâi "unit, piece, after numerals" + -in adj. suffix.
singular isothermal sphere
kore-ye izodamâ-ye takin
Fr.: sphère isotherme singulère
In models of star formation, an isothermal sphere in which the density distribution in the static or nearly static outer envelope obeys an r-2 power law. In the limit of infinite central concentration, the unstable equilibrium approaches the singular isothermal sphere which has the density and mass distributions ρ(r) = (a2/2πG)r-2 and M(r) = (2a2/G)r, where a is the isothermal → sound speed inside the cloud, G is the → gravitational constant, and r the distance from the center (F. H. Shu, 1977, ApJ 214, 488).
→ singular; → isothermal; → sphere.
Fr.: matrice singulière
A → square matrix that does not have a → matrix inverse.
Fr.: point singulier
The point M0(x0,y0) of the curve F(x,y) = 0, where at least one of the → partial derivatives ∂F/∂x and ∂F/∂y vanishes. See also → ordinary point.
Fr.: solution singulière, ~ particulière
Of partial differential equations, the solution which cannot be obtained from the general solution by particular choice of arbitrary functions. → general solution; → particular solution.
1) Math.: A point at which a given mathematical object is not defined.