christmas became an official us holiday on june 28, 1870.
christmas became an official us holiday on june 28, 1870.
when did christmas become an official us holiday?
june 28 , 1870
Na
Na
section::::nhm of extremal kerr black holes.









































the metric of extremal kerr black hole (formula_5) in boyer–lindquist coordinates can be written in the following two enlightening forms,









































where









































taking the near-horizon limit









































and omitting the tildes, one obtains the near-horizon metric (this is also called "extremal kerr throat" )









































section::::nhm of extremal kerr–newman black holes.









































extremal kerr–newman black holes (formula_11) are described by the metric









































where









































taking the near-horizon transformation









































and omitting the tildes, one obtains the nhm









































section::::nhms of generic black holes.
near-horizon metric