دیسول ِ بکنشتاین disul-e Bekenstein
*Fr.: formule de Bekenstein*
The mathematical expression giving the → *entropy*, *S*, of a
→ *black hole * as a function of the area
of its → *event horizon*, *A*:
*S* = (*kc*^{3}*A*)/(4*G*ħ), where *k* is
→ *Boltzmann's constant*, ħ is the
→ *reduced Planck's constant*, and *G* the
→ *gravitational constant*.
It can also be expressed by *S* = (*kA*)/(4*l*_{P}^{2}),
where *l*_{P} is the → *Planck length*.
The existence of this entropy led to the
prediction of the → *Hawking radiation*, because
an entropy is associated with a temperature
and a temperature to a → *thermal radiation*.
The entropy of a black hole increases continuously because the fall of material
into it increases its area. For Jacob D. Bekenstein (1947-), an Israeli theoretical physicist, who contributed
to the foundation of black hole thermodynamics; → *formula*. |