Black holes

■BLACK HOLE BASICS

Black holes are areas in space where there is a
huge amount of mass in a very small space. The
gravity of this mass is so great that everything in
the area is pulled toward the mass. Even light,
with its tiny mass, is pulled into the center of the
hole. No object can escape the gravitational pull
of a black hole.
Have we ever seen a black hole? No. Actually you
can't see a black hole because no light escapes
the event. Astronomers use other ways to look for
black holes. Since they have large masses and
gravities, they affect the surrounding stars and
systems. They have found evidence of black holes
in the dark centers of galaxies and systems that
emit large amounts of x-rays.

●BLACK HOLE STRUCTURES

When stars start to die, they collapse. Eventually
they can create a white dwarf or a neutron star .
Very large stars can collapse and become almost
infinitely dense . Their gravity increases a
respective amount. As the gravity increases, you
can imagine that everything gets heavy. Nothing
could escape the star's gravity. Now imagine that
dead star with a gravity so strong that light can't
even escape. When light can't get out, you have a
black hole. The Sun is too small to become a
black hole. It takes large stars with even larger
masses to become a black hole.

◆CENTERS OF GALAXIES

We just mentioned that there might be black
holes at the center of galaxies. As astronomers
develop more advanced telescopes they have
been able to see large dark areas at the center of
many galaxies. The dark areas have masses that
can be several billion times the mass of our Sun.
They have determined the large mass by watching
the speed of the stars orbiting close to the center
and on the edges of the galaxy. Things move
faster when the gravity is stronger... Even a
system of stars and planets. It looks like a drain
in your bathtub. The physics are different, but
things go faster as they get closer to the drain.
Things go faster as they get closer to the black
hole.