After general
theory of relativity formulation by Alberta Einstein, Carl Schwarzschild obtained
mathematical description of the space-time geometry around spherical mass.
Calculations showed, that for every mass there exists critical radius, today
called Schwarzchild's radius, which corresponds to so extremal distortion
of the space-time, that after compression of the mass to radius equal to such
radius ocurred closing ot the space-time and cutting of from the rest of
the Universe. From such area cannot escape anything,
even light. Radius is described by simple formula:
where G=6,672·10-11
Nm2/kg2, m- mass, c=3·108 m/s.
For
the Sun, Schwarzschild's radius is equal to 2.9 km and for Earth only 8.8
mm. Of course (fortunately?), it is not possible to squeeze there objects
to such small dimensions. But in case of very heavy stars, gravitational
force is so strong, that it can overcome forces connected with pressure in
their inside.
First ever
black's hole color photography! 